AIM2/20/258/7/25 AIM
b. Pilots or passengers without proper identification that are observed entering a SIDA may be reported to the
Transportation Security Administration (TSA) or airport security and may be subject to civil and criminal fines
and prosecution. Pilots are advised to brief passengers accordingly. Report suspicious activity to the TSA by
calling AOPA’s Airport Watch Program, 866−427−3287. 49 CFR 1540 requires each individual who holds an
airman certificate, medical certificate, authorization, or license issued by the FAA to present it for inspection
upon a request from TSA.
FIG 2−3−43
Sample SIDA Warning Sign
Airport Marking Aids and Signs 2−3−37
2/20/25 AIM
Chapter 3. Airspace
Section 1. General
3−1−1. General
a. There are two categories of airspace or airspace areas:
1. Regulatory (Class A, B, C, D and E airspace areas, restricted and prohibited areas); and
2. Nonregulatory (military operations areas [MOA], warning areas, alert areas, controlled firing areas
[CFA], and national security areas [NSA]).
NOTE−
Additional information on special use airspace (prohibited areas, restricted areas [permanent or temporary], warning
areas, MOAs [permanent or temporary], alert areas, CF As, and NSAs) may be found in Chapter 3, Airspace, Section 4,
Special Use Airspace, paragraphs 3−4−1 through 3−4−8.
b. Within these two categories, there are four types:
1. Controlled,
2. Uncontrolled,
3. Special use, and
4. Other airspace.
c. The categories and types of airspace are dictated by:
1. The complexity or density of aircraft movements,
2. The nature of the operations conducted within the airspace,
3. The level of safety required, and
4. The national and public interest.
d. It is important that pilots be familiar with the operational requirements for each of the various types or
classes of airspace. Subsequent sections will cover each class in sufficient detail to facilitate understanding.
3−1−2. General Dimensions of Airspace Segments
Refer to Title 14 of the U.S. Code of Federal Re gulations (CFR) for specific dimensions, exceptions,
geographical areas covered, exclusions, specific transponder/ADS −B or other equipment requirements, and
flight operations.
3−1−3. Hierarchy of Overlapping Airspace Designations
a. When overlapping airspace designations apply to the same airspace, the operating rules associated with the
more restrictive airspace designation apply.
b. For the purpose of clarification:
1. Class A airspace is more restrictive than Class B, Class C, Class D, Class E, or Class G airspace;
2. Class B airspace is more restrictive than Class C, Class D, Class E, or Class G airspace;
3. Class C airspace is more restrictive than Class D, Class E, or Class G airspace;
4. Class D airspace is more restrictive than Class E or Class G airspace; and
General 3−1−1
AIM 2/20/25
5. Class E is more restrictive than Class G airspace.
3−1−4. Basic VFR Weather Minimums
a. No person may operate an aircraft under basic VFR when the flight visibility is less, or at a distance from
clouds that is less, than that prescribed for the corresponding altitude and class of airspace. (See TBL 3−1−1.)
NOTE−
Student pilots must comply with 14 CFR section 61.89(a) (6) and (7).
b. Except as provided in 14 CFR section 91.157, Special VFR Weather Minimums, no person may operate
an aircraft beneath the ceiling under VFR within the lateral boundaries of controlled airspace designated to the
surface for an airport when the ceiling is less than 1,000 feet. (See 14 CFR section 91.155(c).)
TBL 3−1−1
Basic VFR Weather Minimums
Airspace Flight Visibility Distance from Clouds
Class A ........................................ Not Applicable Not Applicable
Class B ........................................ 3 statute miles Clear of Clouds
Class C ........................................ 3 statute miles 500 feet below
1,000 feet above
2,000 feet horizontal
Class D ........................................ 3 statute miles 500 feet below
1,000 feet above
2,000 feet horizontal
Class E
Less than 10,000 feet MSL ........................ 3 statute miles 500 feet below
1,000 feet above
2,000 feet horizontal
At or above 10,000 feet MSL ...................... 5 statute miles 1,000 feet below
1,000 feet above
1 statute mile horizontal
Class G
1,200 feet or less above the surface (regardless of MSL
altitude).
For aircraft other than helicopters:
Day, except as provided in §91.155(b) ............... 1 statute mile Clear of clouds
Night, except as provided in §91.155(b) ..............
For helicopters:
3 statute miles 500 feet below
1,000 feet above
2,000 feet horizontal
D a y ........................................... ½ statute mile Clear of clouds
Night, except as provided in §91.155(b) ..............
More than 1,200 feet above the surface but less than
10,000 feet MSL.
1 statute mile Clear of clouds
D a y ........................................... 1 statute mile 500 feet below
1,000 feet above
2,000 feet horizontal
Night ......................................... 3 statute miles 500 feet below
1,000 feet above
2,000 feet horizontal
More than 1,200 feet above the surface and at or above
10,000 feet MSL. ................................
5 statute miles 1,000 feet below
1,000 feet above
1 statute mile horizontal
General3−1−2
2/20/25 AIM
3−1−5. VFR Cruising Altitudes and Flight Levels
(See TBL 3−1−2.)
TBL 3−1−2
VFR Cruising Altitudes and Flight Levels
If your magnetic course
(ground track) is:
And you are more than 3,000 feet above the
surface but below 18,000 feet MSL, fly:
And you are above 18,000 feet
MSL to FL 290, fly:
0 to 179 . . . . ............ Odd thousands MSL, plus 500 feet
(3,500; 5,500; 7,500, etc.)
Odd Flight Levels plus 500 feet
(FL 195; FL 215; FL 235, etc.)
180 to 359 . ............. Even thousands MSL, plus 500 feet
(4,500; 6,500; 8,500, etc.)
Even Flight Levels plus 500 feet
(FL 185; FL 205; FL 225, etc.)
General 3−1−3
2/20/25 AIM
Section 2. Controlled Airspace
3−2−1. General
a. Controlled Airspace. A generic term that covers the different classification of airspace (Class A, Class B,
Class C, Class D, and Class E airspace) and defined dimensions within which air traffic control service is
provided to IFR flights and to VFR flights in accordance with the airspace classification. (See FIG 3−2−1.)
b. IFR Requirements. IFR operations in any class of controlled airspace requires that a pilot must file an
IFR flight plan and receive an appropriate ATC clearance.
c. IFR Separation. Standard IFR separation is provided to all aircraft operating under IFR in controlled
airspace.
d. VFR Requirements. It is the responsibility of the pilot to ensure that ATC clearance or radio
communication requirements are met prior to entry into Class B, Class C, or Class D airspace. The pilot retains
this responsibility when receiving ATC radar advisories. (See 14 CFR part 91.)
e. Traffic Advisories. Traffic advisories will be provided to all aircraft as the controller’s work situation
permits.
f. Safety Alerts. Safety Alerts are mandatory services and are provided to ALL aircraft. There are two types
of Safety Alerts:
1. Terrain/Obstruction Alert. A Terrain/Obstruction Alert is issued when, in the controller’s judgment,
an aircraft’s altitude places it in unsafe proximity to terrain and/or obstructions; and
2. Aircraft Conflict/Mode C Intruder Alert. An Aircraft Conflict/Mode C Intruder Alert is issued if the
controller observes another aircraft which places it in an unsafe proximity. When feasible, the controller will offer
the pilot an alternative course of action.
FIG 3−2−1
Airspace Classes
g. Ultralight V ehicles. No person may operate an ultralight vehicle within Class A, Class B, Class C, or Class
D airspace or within the lateral boundaries of the surface area of Class E airspace designated for an airport unless
that person has prior authorization from the ATC facility having jurisdiction over that airspace. (See 14 CFR part
103.)
h. Unmanned Free Balloons. Unless otherwise authorized by ATC, no person may operate an unmanned
free balloon below 2,000 feet above the surface within the lateral boundaries of Class B, Class C, Class D, or
Class E airspace designated for an airport. (See 14 CFR part 101.)
Controlled Airspace 3−2−1
AIM 2/20/25
i. Parachute Jumps. No person may make a parachute jump, and no pilot −in−command may allow a
parachute jump to be made from that aircraft, in or into Class A, Class B, Class C, or Class D airspace without,
or in violation of, the terms of an ATC authorization issued by the ATC facility having jurisdiction over the
airspace. (See 14 CFR part 105.)
3−2−2. Class A Airspace
a. Definition. Generally, that airspace from 18,000 feet MSL up to and including FL 600, including the
airspace overlying the waters within 12 nautical miles off the coast of the 48 contiguous States and Alaska; and
designated international airspace beyond 12 nautical miles off the coast of the 48 contiguous States and Alaska
within areas of domestic radio navigational signal or ATC radar coverage, and within which domestic procedures
are applied.
b. Operating Rules and Pilot/Equipment Requirements. Unless otherwise authorized, all persons must
operate their aircraft under IFR. (See 14 CFR section 71.33, sections 91.167 through 91.193, sections 91.215
through 91.217, and sections 91.225 through 91.227.)
c. Charts. Class A airspace is not specifically charted.
3−2−3. Class B Airspace
a. Definition. Generally, that airspace from the surface to 10,000 feet MSL surrounding the nation’s busiest
airports in terms of IFR operations or passenger enplanements. The configuration of each Class B airspace area
is individually tailored and consists of a surface area and two or more layers (some Class B airspace areas
resemble upside-down wedding cakes), and is designed to contain all published instrument procedures once an
aircraft enters the airspace. An ATC clearance is required for all aircraft to operate in the area, and all aircraft
that are so cleared receive separation services within the airspace. The cloud clearance requirement for VFR
operations is “clear of clouds.”
b. Operating Rules and Pilot/Equipment Requirements. Regardless of weather conditions, an ATC
clearance is required prior to operating within Class B airspace. Pilots should not request a clearance to operate
within Class B airspace unless the requirements of 14 CFR sections 91.131, 91.215, and 91.225 are met. Included
among these requirements are:
1. Unless otherwise authorized by ATC, aircraft must be equipped with an operable two-way radio capable
of communicating with ATC on appropriate frequencies for that Class B airspace.
2. No person may take off or land a civil aircraft at the following primary airports within Class B airspace
unless the pilot−in−command holds at least a private pilot certificate:
(a) Andrews Air Force Base, MD
(b) Atlanta Hartsfield Airport, GA
(c) Boston Logan Airport, MA
(d) Chicago O’Hare Intl. Airport, IL
(e) Dallas/Fort Worth Intl. Airport, TX
(f) Los Angeles Intl. Airport, CA
(g) Miami Intl. Airport, FL
(h) Newark Intl. Airport, NJ
(i) New York Kennedy Airport, NY
(j) New York La Guardia Airport, NY
(k) Ronald Reagan Washington National Airport, DC
3−2−2 Controlled Airspace
2/20/25 AIM
(l) San Francisco Intl. Airport, CA
3. No person may take off or land a civil aircraft at an airport within Class B airspace or operate a civil
aircraft within Class B airspace unless:
(a) The pilot−in−command holds at least a private pilot certificate; or
(b) The pilot−in−command holds a recreational pilot certificate and has met the requirements of 14 CFR
section 61.101; or
(c) The pilot−in−command holds a sport pilot certificate and has met the requirements of 14 CFR section
61.325; or
(d) The aircraft is operated by a student pilot:
(1) Who seeks a private pilot certificate and has met the requirements of 14 CFR section 61.95.
(2) Who seeks a recreational pilot or sport pilot certificate and has met the requirements of 14 CFR
section 61.94.
4. Unless otherwise authorized by ATC, each person operating a large turbine engine-powered airplane to
or from a primary airport must operate at or above the designated floors while within the lateral limits of Class
B airspace.
5. Unless otherwise authorized by ATC, each aircraft must be equipped as follows:
(a) For IFR operations, an operable VOR or TACAN receiver or an operable and suitable RNA V system;
and
(b) For all operations, a two-way radio capable of communications with ATC on appropriate frequencies
for that area; and
(c) Unless otherwise authorized by ATC, an operable radar beacon transponder with automatic altitude
reporting capability and operable ADS−B Out equipment.
NOTE−
ATC may, upon notification, immediately authorize a deviation from the altitude reporting equipment requirement; however,
a request for a deviation from the 4096 transponder equipment requirement must be submitted to the controlling ATC facility
at least one hour before the proposed operation. A request for a deviation from the ADS−B equipage requirement must be
submitted using the F AA’s automated web authorization tool at least one hour but not more than 24 hours before the proposed
operation.
REFERENCE−
AIM, Para 4−1−20, Transponder and ADS−B Out Operation.
AC 90−114, Automatic Dependent Surveillance−Broadcast Operations.
6. Mode C Veil. The airspace within 30 nautical miles of an airport listed in Appendix D, section 1 of 14
CFR part 91 (generally primary airports within Class B airspace areas), from the surface upward to 10,000 feet
MSL. Unless otherwise authorized by ATC, aircraft operating within this airspace must be equipped with an
operable radar beacon transponder with automatic altitude reporting capability and operable ADS −B Out
equipment.
However, aircraft that were not originally certificated with an engine−driven electrical system or that have not
subsequently been certified with a system installed may conduct operations within a Mode C veil provided the
aircraft remains outside Class A, B or C airspace; and below the altitude of the ceiling of a Class B or Class C
airspace area designated for an airport or 10,000 feet MSL, whichever is lower.
c. Charts. Class B airspace is charted on Sectional Charts, IFR En Route Low Altitude, and Terminal Area
Charts.
d. Flight Procedures.
1. Flights. Aircraft within Class B airspace are required to operate in accordan ce with current IFR
procedures. A clearance for a visual approach to a primary airport is not authorization for turbine − powered
airplanes to operate below the designated floors of the Class B airspace.
Controlled Airspace 3−2−3
AIM 2/20/25
2. VFR Flights.
(a) Arriving aircraft must obtain an ATC clearance prior to entering Class B airspace and must contact
ATC on the appropriate frequency, and in relation to geographical fixes shown on local charts. Although a pilot
may be operating beneath the floor of the Class B airspace on initial contact, communications with ATC should
be established in relation to the points indicated for spacing and sequencing purposes.
(b) Departing aircraft require a clearance to depart Class B airspace and should advise the clearance
delivery position of their intended altitude and route of flight. ATC will normally advise VFR aircraft when
leaving the geographical limits of the Class B airspace. Radar service is not automatically terminated with this
advisory unless specifically stated by the controller.
(c) Aircraft not landing or departing the primary airport may obtain an ATC clearance to transit the
Class B airspace when traffic conditions permit and provided the requirements of 14 CFR section 91.131 are met.
Such VFR aircraft are encouraged, to the extent possible, to operate at altitudes above or below the Class B
airspace or transit through established VFR corridors. Pilots operating in VFR corridors are urged to use
frequency 122.750 MHz for the exchange of aircraft position information.
e. ATC Clearances and Separation. An ATC clearance is required to enter and operate within Class B
airspace. VFR pilots are provided sequencing and separation from other aircraft while operating within Class
B airspace.
REFERENCE−
AIM, Para 4−1−18, Terminal Radar Services for VFR Aircraft.
NOTE−
Separation and sequencing of VFR aircraft will be suspended in the event of a radar outage as this service is dependent on
radar . The pilot will be advised that the service is not available and issued wind, runway information and the time or place
to contact the tower.
1. VFR aircraft are separated from all VFR/IFR aircraft which weigh 19,000 pounds or less by a minimum
of:
(a) Target resolution, or
(b) 500 feet vertical separation, or
(c) Visual separation.
2. VFR aircraft are separated from all VFR/IFR aircraft which weigh more than 19,000 and turbojets by
no less than:
(a) 1 1/2 miles lateral separation, or
(b) 500 feet vertical separation, or
(c) Visual separation.
3. This program is not to be interpreted as relieving pilots of their responsibilities to see and avoid other
traffic operating in basic VFR weather conditions, to adjust their operations and flight path as necessary to
preclude serious wake encounters, to maintain appropriate terrain and obstruction clearance or to remain in
weather conditions equal to or better than the minimums required by 14 CFR section 91.155. Approach control
should be advised and a revised clearance or instruction obtained when compliance with an assigned route,
heading and/or altitude is likely to compromise pilot responsibility with respect to terrain and obstruction
clearance, vortex exposure, and weather minimums.
4. ATC may assign altitudes to VFR aircraft that do not conform to 14 CFR section 91.159. “RESUME
APPROPRIATE VFR ALTITUDES” will be broadcast when the altitude assignment is no longer needed for
separation or when leaving Class B airspace. Pilots must return to an altitude that conforms to 14 CFR section
91.159.
f. Proximity Operations. VFR aircraft operating in proximity to Class B airspace are cautioned against
operating too closely to the boundaries, especially where the floor of the Class B airspace is 3,000 feet or less
3−2−4 Controlled Airspace
2/20/25 AIM
above the surface or where VFR cruise altitudes are at or near the floor of higher levels. Observance of this
precaution will reduce the potential for encountering an aircraft operating at the altitudes of Class B floors.
Additionally, VFR aircraft are encouraged to utilize the VFR Planning Chart as a tool for planning flight in
proximity to Class B airspace. Charted VFR Flyway Planning Charts are published on the back of the existing
VFR Terminal Area Charts.
3−2−4. Class C Airspace
a. Definition. Generally, that airspace from the surface to 4,000 feet above the airport elevation (charted in
MSL) surrounding those airports that have an operational control tower, are serviced by a radar approach control,
and that have a certain number of IFR operations or passenger enplanements. Although the configuration of each
Class C airspace area is individually tailored, the airspace usually consists of a 5 NM radius core surface area
that extends from the surface up to 4,000 feet above the airport elevation, and a 10 NM radius shelf area that
extends no lower than 1,200 feet up to 4,000 feet above the airport elevation.
b. Charts. Class C airspace is charted on Sectional Charts, IFR En Route Low Altitude, and Terminal Area
Charts where appropriate.
c. Operating Rules and Pilot/Equipment Requirements:
1. Pilot Certification. No specific certification required.
2. Equipment.
(a) Two-way radio; and
(b) Unless otherwise authorized by ATC, an operable radar beacon transponder with automatic altitude
reporting capability and operable ADS−B Out equipment.
NOTE−
See paragraph 4 −1−20, Transponder and ADS −B Out Operation, subparagraph f for Mode C transponder/ ADS −B
requirements for operating above Class C airspace.
3. Arrival or Through Flight Entry Requirements. Two-way radio communication must be established
with the ATC facility providing ATC services prior to entry and thereafter maintain those communications while
in Class C airspace. Pilots of arriving aircraft should contact the Class C airspace ATC facility on the publicized
frequency and give their position, altitude, radar beacon code, destination, and request Class C service. Radio
contact should be initiated far enough from the Class C airspace boundary to preclude entering Class C airspace
before two-way radio communications are established.
NOTE−
1. If the controller responds to a radio call with, “(aircraft callsign) standby,” radio communications have been established
and the pilot can enter the Class C airspace.
2. If workload or traffic conditions prevent immediate provision of Class C services, the controller will inform the pilot to
remain outside the Class C airspace until conditions permit the services to be provided.
3. It is important to understand that if the controller responds to the initial radio call without using the aircraft identification,
radio communications have not been established and the pilot may not enter the Class C airspace.
4. Class C airspace areas have a procedural Outer Area. Normally this area is 20 NM from the primary Class C airspace
airport. Its vertical limit extends from the lower limits of radio/radar coverage up to the ceiling of the approach control’ s
delegated airspace, excluding the Class C airspace itself, and other airspace as appropriate. (This outer area is not charted.)
5. Pilots approaching an airport with Class C service should be aware that if they descend below the base altitude of the
5 to 10 mile shelf during an instrument or visual approach, they may encounter non−transponder/non−ADS−B VFR aircraft.
EXAMPLE−
1. [Aircraft callsign] “remain outside the Class Charlie airspace and standby.”
2. “Aircraft calling Dulles approach control, standby.”
4. Departures from:
Controlled Airspace 3−2−5
AIM 2/20/25
(a) A primary or satellite airport with an operating control tower. Two-way radio communications must
be established and maintained with the control tower, and thereafter as instructed by ATC while operating in
Class C airspace.
(b) A satellite airport without an operating control tower. Two-way radio communications must be
established as soon as practicable after departing with the ATC facility having jurisdiction over the Class C
airspace.
5. Aircraft Speed. Unless otherwise authorized or required by ATC, no person may operate an aircraft at
or below 2,500 feet above the surface within 4 nautical miles of the primary airport of a Class C airspace area
at an indicated airspeed of more than 200 knots (230 mph).
d. Air Traffic Services. When two-way radio communications and radar contact are established, all VFR
aircraft are:
1. Sequenced to the primary airport.
2. Provided Class C services within the Class C airspace and the outer area.
3. Provided basic radar services beyond the outer area on a workload permitting basis. This can be
terminated by the controller if workload dictates.
e. Aircraft Separation. Separation is provided within the Class C airspace and the outer area after two-way
radio communications and radar contact are established. VFR aircraft are separated from IFR aircraft within the
Class C airspace by any of the following:
1. Visual separation.
2. 500 feet vertical separation.
3. Target resolution.
4. Wake turbulence separation will be provided to all aircraft operating:
(a) Behind and less than 1,000 feet below super or heavy aircraft,
(b) To small aircraft operating behind and less than 500 feet below B757 aircraft, and
(c) To small aircraft following a large aircraft on final approach.
NOTE−
1. Separation and sequencing of VFR aircraft will be suspended in the event of a radar outage as this service is dependent
on radar. The pilot will be advised that the service is not available and issued wind, runway information and the time or place
to contact the tower.
2. Pilot participation is voluntary within the outer area and can be discontinued, within the outer area, at the pilot’ s request.
Class C services will be provided in the outer area unless the pilot requests termination of the service.
3. Some facilities provide Class C services only during published hours. At other times, terminal IFR radar service will be
provided. It is important to note that the communications and transponder/ADS−B requirements are dependent on the class
of airspace established outside of the published hours.
f. Secondary Airports
1. In some locations Class C airspace may overlie the Class D surface area of a secondary airport. In order
to allow that control tower to provide service to aircraft, portions of the overlapping Class C airspace may be
procedurally excluded when the secondary airport tower is in operation. Aircraft operating in these procedurally
excluded areas will only be provided airport traffic control services when in communication with the secondary
airport tower.
2. Aircraft proceeding inbound to a satellite airport will be terminated at a sufficient distance to allow time
to change to the appropriate tower or advisory frequency. Class C services to these aircraft will be discontinued
when the aircraft is instructed to contact the tower or change to advisory frequency.
3−2−6 Controlled Airspace
AIM2/20/257/9/26 AIM
3. Aircraft departing secondary controlled airports will not receive Class C services until they have been
radar identified and two-way communications have been established with the Class C airspace facility.
4. This program is not to be interpreted as relieving pilots of their responsibilities to see and avoid other
traffic operating in basic VFR weather conditions, to adjust their operations and flight path as necessary to
preclude serious wake encounters, to maintain appropriate terrain and obstruction clearance or to remain in
weather conditions equal to or better than the minimums required by 14 CFR section 91.155. Approach control
should be advised and a revised clearance or instruction obtained when compliance with an assigned route,
heading and/or altitude is likely to compromise pilot responsibility with respect to terrain and obstruction
clearance, vortex exposure, and weather minimums.
g. Class C Airspace Areas by State. These states currently have designated Class C airspace areas that are
depicted on sectional charts. Pilots should consult current sectional charts and NOTAMs for the latest
information on services available. Pilots should be aware that some Class C airspace underlies or is adjacent to
Class B airspace. (See TBL 3−2−1.)
TBL 3−2−1
Class C Airspace Areas by State
State/City Airport
ALABAMA
Birmingham .........
Huntsville ...........
Mobile ..............
Birmingham−Shuttlesworth
International
International−Carl T Jones Fld
Regional
ALASKA
Anchorage ........... Ted Stevens International
ARIZONA
Davis−Monthan .......
Tucson ..............
AFB
International
ARKANSAS
Fayetteville (Springdale) Northwest Arkansas Regional
Little Rock .......... Adams Field
CALIFORNIA
Beale ...............
Burbank ............
Fresno ..............
Monterey ............
Oakland .............
Ontario .............
Riverside ............
Sacramento ..........
San Jose ............
Santa Ana ...........
Santa Barbara ........
AFB
Bob Hope
Yosemite International
Peninsula
Metropolitan Oakland
International
International
March AFB
International
Norman Y . Mineta International
John Wayne/Orange County
Municipal
COLORADO
Colorado Springs ..... Municipal
CONNECTICUT
Windsor Locks ....... Bradley International
FLORIDA
Daytona Beach .......
Fort Lauderdale .......
Fort Myers ..........
Jacksonville ..........
Orlando .............
International
Hollywood International
SW Florida Regional
International
Sanford International
State/City Airport
Palm Beach ..........
Pensacola ...........
Pensacola ...........
Sarasota .............
Tallahassee ..........
Whiting .............
President Donald J. Trump Inter-
national
NAS
International
Bradenton International
Regional
NAS
GEORGIA
Savannah ............ Hilton Head International
HAWAII
Kahului ............. Kahului
IDAHO
Boise ............... Air Terminal
ILLINOIS
Champaign .......... Urbana U of Illinois−Willard
Chicago .............
Moline ..............
Peoria ..............
Springfield ..........
Midway International
Quad City International
Greater Peoria Regional
Abraham Lincoln Capital
INDIANA
Evansville ...........
Fort Wayne ..........
Indianapolis ..........
South Bend ..........
Regional
International
International
Regional
IOWA
Cedar Rapids .........
Des Moines ..........
The Eastern Iowa
International
KANSAS
Wichita ............. Mid−Continent
KENTUCKY
Lexington ...........
Louisville ...........
Blue Grass
International−Standiford Field
LOUISIANA
Baton Rouge .........
Lafayette ............
Metropolitan, Ryan Field
Regional
Controlled Airspace 3−2−7
AIM 2/20/25
State/City Airport
Shreveport ........... Regional
MAINE
Bangor .............
Portland .............
International
International Jetport
MICHIGAN
Flint ................
Grand Rapids ........
Lansing .............
Bishop International
Gerald R. Ford International
Capital City
MISSISSIPPI
Columbus ...........
Jackson .............
AFB
Jackson−Evers International
MISSOURI
Springfield .......... Springfield−Branson National
MONTANA
Billings ............. Logan International
NEBRASKA
Lincoln .............
Omaha ..............
Offutt ...............
Lincoln
Eppley Airfield
AFB
NEV ADA
Reno ............... Reno/Tahoe International
NEW HAMPSHIRE
Manchester .......... Manchester
NEW JERSEY
Atlantic City ......... International
NEW MEXICO
Albuquerque ......... International Sunport
NEW YORK
Albany .............
Buffalo .............
Islip ................
Rochester ...........
Syracuse ............
International
Niagara International
Long Island MacArthur
Greater Rochester International
Hancock International
NORTH CAROLINA
Asheville ...........
Fayetteville ..........
Greensboro ..........
Pope ...............
Raleigh .............
Regional
Regional/Grannis Field
Piedmont Triad International
AFB
Raleigh−Durham International
OHIO
Akron ..............
Columbus ...........
Dayton .............
Toledo ..............
Akron−Canton Regional
Port Columbus International
James M. Cox International
Express
OKLAHOMA
Oklahoma City .......
Tinker ..............
Tulsa ...............
Will Rogers World
AFB
International
OREGON
Portland ............. International
State/City Airport
PENNSYLV ANIA
Allentown ........... Lehigh Valley International
PUERTO RICO
San Juan ............ Luis Munoz Marin International
RHODE ISLAND
Providence .......... Theodore Francis Green State
SOUTH CAROLINA
Charleston ...........
Columbia ............
Greer ...............
Myrtle Beach ........
Shaw ...............
AFB/International
Metropolitan
Greenville−Spartanburg
International
Myrtle Beach International
AFB
TENNESSEE
Chattanooga .........
Knoxville ...........
Nashville ............
Lovell Field
McGhee Tyson
International
TEXAS
Abilene .............
Amarillo ............
Austin ..............
Corpus Christi ........
Dyess ..............
El Paso .............
Harlingen ...........
Laughlin ............
Lubbock ............
Midland .............
San Antonio .........
Regional
Rick Husband International
Austin−Bergstrom International
International
AFB
International
Valley International
AFB
Preston Smith International
International
International
VERMONT
Burlington ........... International
VIRGIN ISLANDS
St. Thomas .......... Charlotte Amalie Cyril E. King
VIRGINIA
Richmond ...........
Norfolk .............
International
International
Roanoke ............ Regional/Woodrum Field
WASHINGTON
Point Roberts ........
Spokane ............
Spokane ............
Whidbey Island .......
Vancouver International
Fairchild AFB
International
NAS, Ault Field
WEST VIRGINIA
Charleston ........... Yeager
WISCONSIN
Green Bay ...........
Madison ............
Milwaukee ..........
Austin Straubel International
Dane County Regional−Traux
Field
General Mitchell International
3−2−5. Class D Airspace
a. Definition. Generally, Class D airspace extends upward from the surface to 2,500 feet above the airport
elevation (charted in MSL) surrounding those airports that have an operational control tower. The configuration
3−2−8 Controlled Airspace
2/20/25 AIM
of each Class D airspace area is individually tailored and when instrument procedures are published, the airspace
will normally be designed to contain the procedures.
1. Class D surface areas may be designated as full-time (24 hour tower operations) or part-time. Part-time
Class D effective times are published in the Chart Supplement.
2. Where a Class D surface area is part-time, the airspace may revert to either a Class E surface area (see
paragraph 3−2−6e1) or Class G airspace. When a part–time Class D surface area changes to Class G, the surface
area becomes Class G airspace up to, but not including, the overlying controlled airspace.
NOTE−
1. The airport listing in the Chart Supplement will state the part–time surface area status (for example, “other times CLASS
E” or “other times CLASS G”).
2. Normally, the overlying controlled airspace is the Class E transition area airspace that begins at either 700 feet AGL
(charted as magenta vignette) or 1200 feet AGL (charted as blue vignette). This may be determined by consulting the
applicable VFR Sectional or Terminal Area Charts.
b. Operating Rules and Pilot/Equipment Requirements:
1. Pilot Certification. No specific certification required.
2. Equipment. Unless otherwise authorized by ATC, an operable two−way radio is required.
3. Arrival or Through Flight Entry Requirements. Two−way radio communication must be established
with the ATC facility providing ATC services prior to entry and thereafter maintain those communications while
in the Class D airspace. Pilots of arriving aircraft should contact the control tower on the publicized frequency
and give their position, altitude, destination, and any request(s). Radio contact should be initiated far enough
from the Class D airspace boundary to preclude entering the Class D airspace before two −way radio
communications are established.
NOTE−
1. If the controller responds to a radio call with, “[aircraft callsign] standby,” radio communications have been established
and the pilot can enter the Class D airspace.
2. If workload or traffic conditions prevent immediate entry into Class D airspace, the controller will inform the pilot to
remain outside the Class D airspace until conditions permit entry.
EXAMPLE−
1. “[Aircraft callsign] remain outside the Class Delta airspace and standby.”
It is important to understand that if the controller responds to the initial radio call without using the aircraft callsign, radio
communications have not been established and the pilot may not enter the Class D airspace.
2. “Aircraft calling Manassas tower standby.”
At those airports where the control tower does not operate 24 hours a day, the operating hours of the tower will be listed
on the appropriate charts and in the Chart Supplement. During the hours the tower is not in operation, the Class E surface
area rules or a combination of Class E rules to 700 feet above ground level and Class G rules to the surface will become
applicable. Check the Chart Supplement for specifics.
4. Departures from:
(a) A primary or satellite airport with an operating control tower. Two-way radio communications must
be established and maintained with the control tower, and thereafter as instructed by ATC while operating in the
Class D airspace.
(b) A satellite airport without an operating control tower. Two-way radio communications must be
established as soon as practicable after departing with the ATC facility having jurisdiction over the Class D
airspace as soon as practicable after departing.
5. Aircraft Speed. Unless otherwise authorized or required by ATC, no person may operate an aircraft at
or below 2,500 feet above the surface within 4 nautical miles of the primary airport of a Class D airspace area
at an indicated airspeed of more than 200 knots (230 mph).
Controlled Airspace 3−2−9
AIM 2/20/253/15/077110.65R CHG 2AIM 8/7/25
c. Class D airspace areas are depicted on Sectional and Terminal charts with blue segmented lines, and on IFR
En Route Lows with a boxed [D].
d. Surface area arrival extensions:
1. Class D surface area arrival extensions for instrument approach procedures may be Class D or Class E
airspace. As a general rule, if all extensions are 2 miles or less, they remain part of the Class D surface area.
However, if any one extension is greater than 2 miles, then all extensions will be Class E airspace.
2. Surface area arrival extensions are effective during the published times of the surface area. For part–time
Class D surface areas that revert to Class E airspace, the arrival extensions will remain in effect as Class E
airspace. For part–time Class D surface areas that change to Class G airspace, the arrival extensions will become
Class G at the same time.
e. Separation for VFR Aircraft. No separation services are provided to VFR aircraft.
3−2−6. Class E Airspace
a. Definition. Class E airspace is controlled airspace that is designated to serve a variety of terminal or en
route purposes as described in this paragraph.
b. Operating Rules and Pilot/Equipment Requirements:
1. Pilot Certification. No specific certification required.
2. Equipment. Unless otherwise authorized by ATC:
(a) An operable radar beacon transponder with automatic altitude reporting capability and operable
ADS−B Out equipment are required at and above 10,000 feet MSL within the 48 contiguous states and the
District of Columbia, excluding the airspace at and below 2,500 feet above the surface, and
(b) Operable ADS−B Out equipment at and above 3,000 feet MSL over the Gulf of America from the
coastline of the United States out to 12 nautical miles.
NOTE−
The airspace described in (b) is specified in 14 CFR § 91.225 for ADS−B Out requirements. However, 14 CFR § 91.215 does
not include this airspace for transponder requirements.
3. Arrival or Through Flight Entry Requirements. No specific requirements.
c. Charts. Class E airspace below 14,500 feet MSL is charted on Sectional, Terminal, and IFR Enroute Low
Altitude charts.
d. Vertical limits. Except where designated at a lower altitude (see paragraph 3−2−6e, below, for specifics),
Class E airspace in the United States consists of:
1. The airspace extending upward from 14,500 feet MSL to, but not including, 18,000 feet MSL overlying
the 48 contiguous states, the District of Columbia and Alaska, including the waters within nautical 12 miles from
the coast of the 48 contiguous states and Alaska; excluding:
(a) The Alaska peninsula west of longitude 16000'00''W.; and
(b) The airspace below 1,500 feet above the surface of the earth unless specifically designated lower (for
example, in mountainous terrain higher than 13,000 feet MSL).
2. The airspace above FL 600 is Class E airspace.
e. Functions of Class E Airspace. Class E airspace may be designated for the following purposes:
1. Surface area designated for an airport where a control tower is not in operation. Class E surface
areas extend upward from the surface to a designated altitude, or to the adjacent or overlying controlled airspace.
The airspace will be configured to contain all instrument procedures.
(a) To qualify for a Class E surface area, the airport must have weather observation and reporting
capability, and communications capability must exist with aircraft down to the runway surface.
3−2−10 Controlled Airspace
2/20/25 AIM
(b) A Class E surface area may also be designated to accommodate part-time operations at a Class C or
Class D airspace location (for example, those periods when the control tower is not in operation).
(c) Pilots should refer to the airport page in the applicable Chart Supplement for surface area status
information.
2. Extension to a surface area. Class E airspace may be designated as extensions to Class B, Class C,
Class D, and Class E surface areas. Class E airspace extensions begin at the surface and extend up to the overlying
controlled airspace. The extensions provide contro lled airspace to contain st andard instrument approach
procedures without imposing a communications requirement on pilots operating under VFR. Surface area arrival
extensions become part of the surface area and are in effect during the same times as the surface area.
NOTE−
When a Class C or Class D surface area is not in effect continuously (for example, where a control tower only operates
part-time), the surface area airspace will change to either a Class E surface area or Class G airspace. In such cases, the
“Airspace” entry for the airport in the Chart Supplement will state “other times Class E” or “other times Class G.” When
a part-time surface area changes to Class E airspace, the Class E arrival extensions will remain in effect as Class E airspace.
If a part–time Class C, Class D, or Class E surface area becomes Class G airspace, the arrival extensions will change to
Class G at the same time.
3. Airspace used for transition. Class E airspace areas may be designated for transitioning aircraft
to/from the terminal or en route environment.
(a) Class E transition areas extend upward from either 700 feet AGL (shown as magenta vignette on
sectional charts) or 1,200 feet AGL (blue vignette) and are designated for airports with an approved instrument
procedure.
(b) The 700-foot/1200-foot AGL Class E airspace tr ansition areas remain in effect continuously,
regardless of airport operating hours or surface area status.
NOTE−
Do not confuse the 700-foot and 1200-foot Class E transition areas with surface areas or surface area extensions.
4. En Route Domestic Areas. There are Class E airspace areas that extend upward from a specified
altitude and are en route domestic airspace areas that provide controlled airspace in those areas where there is
a requirement to provide IFR en route ATC services but the Federal airway system is inadequate.
5. Federal Airways and Low-Altitude RNA V Routes. Federal airways and low-altitude RNA V routes are
Class E airspace areas and, unless otherwise specified, extend upward from 1,200 feet AGL to, but not
including,18,000 feet MSL.
(a) Federal airways consist of Low/Medium Frequency (L/MF) airways (colored Federal airways) and
VOR Federal airways.
(1) L/MF airways are based on non−directional beacons (NDB) and are identified as green, red, amber,
or blue.
(2) VOR Federal airways are based on VOR/VORTAC facilities and are identified by a “V” prefix.
(b) Low-altitude RNA V routes consist of T-routes and helicopter RNA V routes (TK-routes).
NOTE−
See AIM paragraph 5−3−4, Airways and Route Systems, for more details and charting information.
6. Offshore Airspace Areas. There are Class E airspace areas that extend upward from a specified altitude
to, but not including, 18,000 feet MSL and are designated as offshore airspace areas. These areas provide
controlled airspace beyond 12 miles from the coast of the U.S. in those areas where there is a requirement to
provide IFR en route ATC services and within which the U.S. is applying domestic procedures.
f. Separation for VFR Aircraft. No separation services are provided to VFR aircraft.
Controlled Airspace 3−2−11
2/20/25 AIM
Section 3. Class G Airspace
3−3−1. General
Class G airspace (uncontrolled) is that portion of airspace that has not been designated as Class A, Class B, Class
C, Class D, or Class E airspace.
3−3−2. VFR Requirements
Rules governing VFR flight have been adopted to assist the pilot in meeting the responsibility to see and avoid
other aircraft. Minimum flight visibility and distance from clouds required for VFR flight are contained in
14 CFR section 91.155. (See TBL 3−1−1.)
3−3−3. IFR Requirements
a. Title 14 CFR specifies the pilot and aircraft equipment requirements for IFR flight. Pilots are reminded that
in addition to altitude or flight level requirements, 14 CFR section 91.177 includes a requirement to remain at
least 1,000 feet (2,000 feet in designated mountainous terrain) above the highest obstacle within a horizontal
distance of 4 nautical miles from the course to be flown.
b. IFR Altitudes. (See TBL 3−3−1.)
TBL 3−3−1
IFR Altitudes
Class G Airspace
If your magnetic course
(ground track) is: And you are below 18,000 feet MSL, fly:
0 to 179 Odd thousands MSL, (3,000; 5,000; 7,000, etc.)
180 to 359 Even thousands MSL, (2,000; 4,000; 6,000, etc.)
Class G Airspace 3−3−1
2/20/25 AIM
Section 4. Special Use Airspace
3−4−1. General
a. Special use airspace (SUA) consists of that airspace wherein activities must be confined because of their
nature, or wherein limitations are imposed upon aircraft operations that are not a part of those activities, or both.
SUA areas are depicted on aeronautical charts, except for controlled firing areas (CFA), temporary military
operations areas (MOA), and temporary restricted areas.
b. Prohibited and restricted areas are regulatory special use airspace and are established in 14 CFR part 73
through the rulemaking process.
c. Warning areas, MOAs, alert areas, CFAs, and national security areas (NSA) are nonregulatory special use
airspace.
d. Special use airspace descriptions (except CFAs) are contained in FAA Order JO 7400.10, Special Use
Airspace.
e. Permanent SUA (except CFAs) is charted on Sectional Aeronautical, VFR Terminal Area, and applicable
En Route charts, and include the hours of operation, altitudes, and the controlling agency.
NOTE−
For temporary restricted areas and temporary MOAs, pilots should review the Domestic Notices found on the Federal
NOTAM System (FNS) NOTAM Search website under External Links or the Air Traffic Plans and Publications website, the
F AA SUA website, and/or contact the appropriate overlying ATC facility to determine the effect of non−depicted SUA areas
along their routes of flight.
3−4−2. Prohibited Areas
Prohibited areas contain airspace of defined dimensions identified by an area on the surface of the earth within
which the flight of aircraft is prohibited. Such areas are established for security or other reasons associated with
the national welfare. These areas are published in the Federal Register and are depicted on aeronautical charts.
3−4−3. Restricted Areas
a. Restricted areas contain airspace identified by an area on the surface of the earth within which the flight
of aircraft, while not wholly prohibited, is subject to restrictions. Activities within these areas must be confined
because of their nature or limitations imposed upon aircraft operations that are not a part of those activities or
both. Restricted areas denote the existence of unusual, often invisible, hazards to aircraft such as artillery firing,
aerial gunnery, or guided missiles. Penetration of restricted areas without authorization from the using or
controlling agency may be extremely hazardous to the aircraft and its occupants. Restricted areas are published
in the Federal Register and constitute 14 CFR part 73.
b. ATC facilities apply the following procedures when aircraft are operating on an IFR clearance (including
those cleared by ATC to maintain VFR-on-top) via a route which lies within joint-use restricted airspace.
1. If the restricted area is not active and has been released to the controlling agency (FAA), the ATC facility
will allow the aircraft to operate in the restricted airspace without issuing specific clearance for it to do so.
2. If the restricted area is active and has not been released to the controlling agency (FAA), the ATC facility
will issue a clearance which will ensure the aircraft avoids the restricted airspace unless it is on an approved
altitude reservation mission or has obtained its own permission to operate in the airspace and so informs the
controlling facility.
NOTE−
The above apply only to joint-use restricted airspace and not to prohibited and nonjoint-use airspace. For the latter
Special Use Airspace 3−4−1
AIM 2/20/25
categories, the ATC facility will issue a clearance so the aircraft will avoid the restricted airspace unless it is on an approved
altitude reservation mission or has obtained its own permission to operate in the airspace and so informs the controlling
facility.
c. Permanent restricted areas are charted on Sectional Aeronautical, VFR Terminal Area, and the appropriate
En Route charts.
NOTE−
Temporary restricted areas are not charted.
3−4−4. Warning Areas
A warning area is airspace of defined dimensions, extending from three nautical miles outward from the coast
of the U.S., that contains activity that may be hazardous to nonparticipating aircraft. The purpose of such warning
areas is to warn nonparticipating pilots of the potential danger. A warning area may be located over domestic
or international waters or both.
3−4−5. Military Operations Areas
a. MOAs consist of airspace of defined vertical and lateral limits established for the purpose of separating
certain military training activities from IFR traffic. Whenever a MOA is being used, nonparticipating IFR traffic
may be cleared through a MOA if IFR separation can be provided by ATC. Otherwise, ATC will reroute or restrict
nonparticipating IFR traffic.
b. Examples of activities conducted in MOAs include, but are not limited to: air combat tactics, air intercepts,
aerobatics, formation training, and low−altitude tactics. Military pilots flying in an active MOA are exempted
from the provisions of 14 CFR section 91.303(c) and (d) which prohibits aerobatic flight within Class D and Class
E surface areas, and within Federal airways. Additionally, the Department of Defense has been issued an
authorization to operate aircraft at indicated airspeeds in excess of 250 knots below 10,000 feet MSL within
active MOAs.
c. Pilots operating under VFR should exercise extreme caution while flying within a MOA when military
activity is being conducted. The activity status (active/inactive) of MOAs may change frequently. Therefore,
pilots should contact any FSS within 100 miles of the area to obtain accurate real-time information concerning
the MOA hours of operation. Prior to entering an active MOA, pilots should contact the controlling agency for
traffic advisories.
d. Permanent MOAs are charted on Sectional Aeronautical, VFR Terminal Area, and the appropriate En
Route Low Altitude charts.
NOTE−
Temporary MOAs are not charted.
3−4−6. Alert Areas
Alert areas are depicted on aeronautical charts to inform nonparticipating pilots of areas that may contain a high
volume of pilot training or an unusual type of aerial activity. Pilots should be particularly alert when flying in
these areas. All activity within an alert area must be conducted in accordance with CFRs, without waiver, and
pilots of participating aircraft as well as pilots transiting the area must be equally responsible for collision
avoidance.
3−4−7. Controlled Firing Areas
CFAs contain activities which, if not conducted in a controlled environment, could be hazardous to
nonparticipating aircraft. The distinguishing feature of the CFA, as compared to other special use airspace, is that
its activities are suspended immediately when spotter aircraft, radar, or ground lookout positions indicate an
aircraft might be approaching the area. There is no need to chart CFAs since they do not cause a nonparticipating
aircraft to change its flight path.
3−4−2 Special Use Airspace
2/20/25 AIM
3−4−8. National Security Areas
NSAs consist of airspace of defined vertical and lateral dimensions established at locations where there is a
requirement for increased security and safety of ground facilities. Pilots are requested to voluntarily avoid flying
through the depicted NSA. When it is necessary to provide a greater level of security and safety, flight in NSAs
may be temporarily prohibited by regulation under the provisions of 14 CFR section 99.7. Regulatory
prohibitions will be issued by System Operations Security and disseminated via NOTAM. Inquiries about NSAs
should be directed to System Operations Security.
REFERENCE−
AIM, Para 5−6−1, National Security
3−4−9. Obtaining Special Use Airspace Status
a. Pilots can request the status of SUA by contacting the using or controlling agency. The frequency for the
controlling agency is tabulated in the margins of the applicable IFR and VFR charts.
b. An airspace NOTAM will be issued for SUA when the SUA airspace (permanent and/or temporary)
requires a NOTAM for activation. Pilots should check ARTCC NOTAMs for airspace activation.
c. Special Use Airspace Information Service (SUAIS) (Alaska Only). The SUAIS is a 24−hour service
operated by the military that provides civilian pilots, flying VFR, with information regarding military flight
operations in certain MOAs and restricted airspace within central Alaska. The service provides “near real time”
information on military flight activity in the interior Alaska MOA and Restricted Area complex. SUAIS also
provides information on artillery firing, known helicopter operations, and unmanned aerial vehicle operations.
Pilots flying VFR are encouraged to use SUAIS. See the Alaska Chart Supplement for hours of operation, phone
numbers, and radio frequencies.
d. Special use airspace scheduling data for preflight planning is available via the FAA SUA website.
Special Use Airspace 3−4−3
2/20/25 AIM
Section 5. Other Airspace Areas
3−5−1. Airport Advisory/Information Services
a. There are two advisory type services available at selected airports.
1. Local Airport Advisory (LAA) service is available only in Alaska and is operated within 10 statute miles
of an airport where a control tower is not operating but where a FSS is located on the airport. At such locations,
the FSS provides a complete local airport advisory service to arriving and departing aircraft. During periods of
fast changing weather the FSS will automatically provide Final Guard as part of the service from the time the
aircraft reports “on −final” or “taking −the−active−runway” until the aircraft reports “on −the−ground” or
“airborne.”
NOTE−
Current policy, when requesting remote ATC services, requires that a pilot monitor the automated weather broadcast at the
landing airport prior to requesting ATC services. The FSS automatically provides Final Guard, when appropriate, during
LAA/Remote Airport Advisory (RAA) operations. Final Guard is a value added wind/altimeter monitoring service, which
provides an automatic wind and altimeter check during active weather situations when the pilot reports on−final or taking
the active runway. During the landing or take−off operation when the winds or altimeter are actively changing the FSS will
blind broadcast significant changes when the specialist believes the change might affect the operation. Pilots should
acknowledge the first wind/altimeter check but due to cockpit activity no acknowledgement is expected for the blind
broadcasts. It is prudent for a pilot to report on−the−ground or airborne to end the service.
2. Remote Airport Information Service (RAIS) is provided in support of short term special events like small
to medium fly−ins. The service is advertised by NOTAM D only. The FSS will not have access to a continuous
readout of the current winds and altimeter; therefore, RAIS does not include weather and/or Final Guard service.
However, known traffic, special event instructions, and all other services are provided.
NOTE−
The airport authority and/or manager should request RAIS support on official letterhead directly with the manager of the
FSS that will provide the service at least 30 days in advance. Approval authority rests with the FSS manager and is based
on workload and resource availability.
REFERENCE−
AIM, Para 4−1−9, Traffic Advisory Practices at Airports Without Operating Control Towers.
b. It is not mandatory that pilots participate in the Airport Advisory programs. Participation enhances safety
for everyone operating around busy GA airports; therefore, everyone is encouraged to participate and provide
feedback that will help improve the program.
3−5−2. Military Training Routes
a. National security depends largely on the deterrent effect of our airborne military forces. To be proficient,
the military services must train in a wide range of airborne tactics. One phase of this training involves “low level”
combat tactics. The required maneuvers and high sp eeds are such that they may occasionally make the
see-and-avoid aspect of VFR flight more difficult without increased vigilance in areas containing such
operations. In an effort to ensure the greatest practical level of safety for all flight operations, the Military
Training Route (MTR) program was conceived.
b. The MTR program is a joint venture by the FAA and the Department of Defense (DoD). MTRs are mutually
developed for use by the military for the purpose of conducting low-altitude, high-speed training. The routes
above 1,500 feet AGL are developed to be flown, to the maximum extent possible, under IFR. The routes at 1,500
feet AGL and below are generally developed to be flown under VFR.
c. Generally, MTRs are established below 10,000 feet MSL for operations at speeds in excess of 250 knots.
However, route segments may be defined at higher altitudes for purposes of route continuity. For example, route
segments may be defined for descent, climbout, and mountainous terrain. There are IFR and VFR routes as
follows:
Other Airspace Areas 3−5−1
AIM 2/20/25
1. IFR Military Training Routes−(IR). Operations on these routes are conducted in accordance with IFR
regardless of weather conditions.
2. VFR Military Training Routes−(VR). Operations on these routes are conducted in accordance with
VFR except flight visibility must be 5 miles or more; and flights must not be conducted below a ceiling of less
than 3,000 feet AGL.
d. Military training routes will be identified and charted as follows:
1. Route identification.
(a) MTRs with no segment above 1,500 feet AGL must be identified by four number characters; e.g.,
IR1206, VR1207.
(b) MTRs that include one or more segments above 1,500 feet AGL must be identified by three number
characters; e.g., IR206, VR207.
(c) Alternate IR/VR routes or route segments are identified by using the basic/principal route designation
followed by a letter suffix, e.g., IR008A, VR1007B, etc.
2. Route charting.
(a) IFR Enroute Low Altitude Chart. This chart will depict all IR routes and all VR routes that
accommodate operations above 1,500 feet AGL.
(b) VFR Sectional Aeronautical Charts. These charts will depict military training activities such as IR
and VR information. Special Military Activity Routes (SMARs) may also be charted on the VFR Sectional Chart,
showing the extent of the airspace allocated to the associated IFR Military Training Routes within which the
Department of Defense conducts periodic operations involving Unmanned Aircraft Systems. These aircraft may
be accompanied by military or other aircraft that provide the pilots of the Unmanned Aircraft Systems visual
observation information about other aircraft operations near them. Further information on SMAR charting can
be found on the border of the printed VFR Sectional Chart and in the FAA Aeronautical Chart Users’ Guide
available online at: https://www.faa.gov/air_traffic/flight_info/aeronav/digital_products/aero_guide/.
(c) Area Planning (AP/1B) Chart (DoD Flight Information Publication −FLIP). This chart is
published by the National Geospatial −Intelligence Agency (NGA) primarily for military users and contains
detailed information on both IR and VR routes.
REFERENCE−
AIM, Para 9−1−6, Subpara a, National Geospatial−Intelligence Agency (NGA) Products.
e. DoD FLIP− Department of Defense Flight Information Publications describe IR/VR routes through charts
and narratives, and the FAA provides information regarding these routes to all users via IFR and VFR charts.
NOTE−
DoD users that require copies of FLIP should contact:
Defense Logistics Agency for Aviation
Mapping Customer Operations (DLA AVN/QAM)
8000 Jefferson Davis Highway
Richmond, VA 23297−5339
Toll free phone: 1−800−826−0342
Commercial: 804−279−6500
MTR information from the FLIP is available for pilot briefings through Flight Service. (See subparagraph f
below.)
f. Availability of MTR information.
1. Pilots may obtain preflight MTR information through Flight Service (see paragraph 5 −1−1, Preflight
Preparation).
2. MTR routes are depicted on IFR En Route Low Altitude Charts and VFR Sectional Charts, which are
available for free download on the FAA website at
https://www.faa.gov/air_traffic/flight_info/aeronav/digital_products/.
3−5−2 Other Airspace Areas
2/20/25 AIM
g. Nonparticipating aircraft are not prohibited from flying within an MTR or SMAR; however, extreme
vigilance should be exercised when conducting flight through or near these routes. Pilots, while inflight, should
contact the FSS within 100 NM of a particular MTR to obtain current information or route usage in their vicinity.
Information available includes times of scheduled activity, altitudes in use on each route segment, and actual
route width. Route width varies for each MTR and can extend several miles on either side of the charted MTR
centerline. Route width information for IFR Military Training Route (IR) and VFR Military Training Route (VR)
MTRs is also available in the FLIP AP/1B along with additional MTR (slow routes/air refueling routes)
information. When requesting MTR information, pilots should give the FSS the MTR designation of interest,
their position, route of flight, and destination in order to reduce frequency congestion and permit the FSS
specialist to identify the MTR or SMAR that could be a factor.
3−5−3. Temporary Flight Restrictions
a. General. This paragraph describes the types of conditions under which the FAA may impose temporary
flight restrictions. It also explains which FAA elements have been delegated authority to issue a temporary flight
restrictions NOTAM and lists the types of responsible agencies/offices from which the FAA will accept requests
to establish temporary flight restrictions. The 14 CFR is explicit as to what operations are prohibited, restricted,
or allowed in a temporary flight restrictions area. Pilots are responsible to comply with 14 CFR sections 91.137,
91.138, 91.141 and 91.143 when conducting flight in an area where a temporary flight restrictions area is in
effect, and should check appropriate NOTAMs during flight planning.
b. The purpose for establishing a temporary flight restrictions area is to:
1. Protect persons and property in the air or on the surface from an existing or imminent hazard associated
with an incident on the surface when the presence of low flying aircraft would magnify, alter, spread, or
compound that hazard (14 CFR section 91.137(a)(1));
2. Provide a safe environment for the operation of disaster relief aircraft (14 CFR section 91.137(a)(2)); or
3. Prevent an unsafe congestion of sightseeing aircraft above an incident or event which may generate a high
degree of public interest (14 CFR section 91.137(a)(3)).
4. Protect declared national disasters for humanita rian reasons in the State of Hawaii (14 CFR
section 91.138).
5. Protect the President, Vice President, or other public figures (14 CFR section 91.141).
6. Provide a safe environment for space agency operations (14 CFR section 91.143).
c. Except for hijacking situations, when the provisions of 14 CFR section 91.137(a)(1) or (a)(2) are necessary,
a temporary flight restrictions area will only be established by or through the area manager at the Air Route
Traffic Control Center (ARTCC) having jurisdiction over the area concerned. A temporary flight restrictions
NOTAM involving the conditions of 14 CFR section 91.137(a)(3) will be issued at the direction of the service
area office director having oversight of the airspace concerned. When hijacking situations are involved, a
temporary flight restrictions area will be implemented through the TSA Aviation Command Center. The
appropriate FAA air traffic element, upon receipt of such a request, will establish a temporary flight restrictions
area under 14 CFR section 91.137(a)(1).
d. The FAA accepts recommendations for the establishment of a temporary flight restrictions area under
14 CFR section 91.137(a)(1) from military major command headquarters, regional directors of the Office of
Emergency Planning, Civil Defense State Directors, State Governors, or other similar authority. For the
situations involving 14 CFR section 91.137(a)(2), the FAA accepts recommendations from military commanders
serving as regional, subregional, or Search and Rescue (SAR) coordinators; by military commanders directing
or coordinating air operations associated with disaster relief; or by civil authorities directing or coordinating
organized relief air operations (includes representatives of the Office of Emergency Planning, U.S. Forest
Service, and State aeronautical agencies). Appropria te authorities for a temporary flight restrictions
establishment under 14 CFR section 91.137(a)(3) are any of those listed above or by State, county, or city
government entities.
Other Airspace Areas 3−5−3
AIM 2/20/25
e. The type of restrictions issued will be kept to a minimum by the FAA consistent with achievement of the
necessary objective. Situations which warrant the extreme restrictions of 14 CFR section 91.137(a)(1) include,
but are not limited to: toxic gas leaks or spills, flammable agents, or fumes which if fanned by rotor or propeller
wash could endanger persons or property on the surface, or if entered by an aircraft could endanger persons or
property in the air; imminent volcano eruptions which could endanger airborne aircraft and occupants; nuclear
accident or incident; and hijackings. Situations which warrant the restrictions associated with 14 CFR
section 91.137(a)(2) include: forest fires which are being fought by releasing fire retardants from aircraft; and
aircraft relief activities following a disaster (earthquake, tidal wave, flood, etc.). 14 CFR section 91.137(a)(3)
restrictions are established for events and incidents that would attract an unsafe congestion of sightseeing aircraft.
f. The amount of airspace needed to protect persons and property or provide a safe environment for
rescue/relief aircraft operations is normally limited to within 2,000 feet above the surface and within a
3−nautical−mile radius. Incidents occurring within Class B, Class C, or Class D airspace will normally be
handled through existing procedures and should not require the issuance of a temporary flight restrictions
NOTAM. Temporary flight restrictions affecting airspace outside of the U.S. and its territories and possessions
are issued with verbiage excluding that airspace outside of the 12−mile coastal limits.
g. The FSS nearest the incident site is normally the “coordination facility.” When FAA communications
assistance is required, the designated FSS will function as the primary communications facility for coordination
between emergency control authorities and affected aircraft. The ARTCC may act as liaison for the emergency
control authorities if adequate communications cannot be established between the designated FSS and the relief
organization. For example, the coordination facility may relay authorizations from the on-scene emergency
response official in cases where news media aircraft operations are approved at the altitudes used by relief
aircraft.
h. ATC may authorize operations in a temporary flight restrictions area under its own authority only when
flight restrictions are established under 14 CFR section 91.137(a)(2) and (a)(3). The appropriate ARTCC/airport
traffic control tower manager will, however, ensure that such authorized flights do not hamper activities or
interfere with the event for which restrictions were implemented. However, ATC will not authorize local IFR
flights into the temporary flight restrictions area.
i. To preclude misunderstanding, the implementing NOTAM will contain specific and formatted information.
The facility establishing a temporary flight restrictions area will format a NOTAM beginning with the phrase
“FLIGHT RESTRICTIONS” followed by: the location of the temporary flight restrictions area; the effective
period; the area defined in statute miles; the altitudes affected; the FAA coordination facility and commercial
telephone number; the reason for the temporary flight restrictions; the agency directing any relief activities and
its commercial telephone number; and other information considered appropriate by the issuing authority.
EXAMPLE−
1. 14 CFR section 91.137(a)(1):
The following NOTAM prohibits all aircraft operations except those specified in the NOTAM.
Flight restrictions Matthews, Virginia, effective immediately until 9610211200. Pursuant to 14 CFR section 91.137(a)(1)
temporary flight restrictions are in effect. Rescue operations in progress. Only relief aircraft operations under the direction
of the Department of Defense are authorized in the airspace at and below 5,000 feet MSL within a 2−nautical−mile radius
of Laser AFB, Matthews, Virginia. Commander, Laser AFB, in charge (897) 946 −5543 (122.4). Steenson FSS
(792) 555−6141 (123.1) is the F AA coordination facility.
2. 14 CFR section 91.137(a)(2):
The following NOTAM permits flight operations in accordance with 14 CFR section 91.137(a)(2). The on-site emergency
response official to authorize media aircraft operations below the altitudes used by the relief aircraft. Flight restrictions 25
miles east of Bransome, Idaho, effective immediately until 9601202359 UTC. Pursuant to 14 CFR section 91.137(a)(2)
temporary flight restrictions are in effect within a 4−nautical−mile radius of the intersection of county roads 564 and 315
at and below 3,500 feet MSL to provide a safe environment for fire fighting aircraft operations. Davis County sheriff’ s
department (792) 555−8122 (122.9) is in charge of on-scene emergency response activities. Glivings FSS (792) 555−1618
(122.2) is the F AA coordination facility.
3−5−4 Other Airspace Areas
2/20/25 AIM
3. 14 CFR section 91.137(a)(3):
The following NOTAM prohibits sightseeing aircraft operations.
Flight restrictions Brown, Tennessee, due to olympic activity. Effective 9606181100 UTC until 9607190200 UTC. Pursuant
to 14 CFR section 91.137(a)(3) temporary fli ght restrictions are in effect within a 3 −nautical− mile radius of
N355783/W835242 and Volunteer VORTAC 019 degree radial 3.7 DME fix at and below 2,500 feet MSL. Norton FSS (423)
555−6742 (126.6) is the F AA coordination facility.
4. 14 CFR section 91.138:
The following NOTAM prohibits all aircraft except those operating under the authorization of the official in charge of
associated emergency or disaster relief response activities, aircraft carrying law enforcement officials, aircraft carrying
personnel involved in an emergency or legitimate scientific purposes, carrying properly accredited news media, and aircraft
operating in accordance with an ATC clearance or instruction.
Flight restrictions Kapalua, Hawaii, effective 9605101200 UTC until 9605151500 UTC. Pursuant to 14 CFR
section 91.138 temporary flight restrictions are in effect within a 3 −nautical−mile radius of N205778/W1564038 and
Maui/OGG/VORTAC 275 degree radial at 14.1 nautical miles. John Doe 808 −757−4469 or 122.4 is in charge of the
operation. Honolulu/HNL 808−757−4470 (123.6) FSS is the FAA coordination facility.
5. 14 CFR section 91.141:
The following NOTAM prohibits all aircraft.
Flight restrictions Stillwater, Oklahoma, June 21, 1996. Pursuant to 14 CFR section 91.141 aircraft flight operations are
prohibited within a 3−nautical−mile radius, below 2000 feet AGL of N360962/W970515 and the Stillwater/SWO/VOR/DME
176 degree radial 3.8−nautical−mile fix from 1400 local time to 1700 local time June 21, 1996, unless otherwise authorized
by ATC.
6. 14 CFR section 91.143:
The following NOTAM prohibits any aircraft of U.S. registry, or pilot any aircraft under the authority of an airman certificate
issued by the F AA.
Kennedy space center space operations area effective immediately until 9610152100 UTC. Pursuant to 14 CFR section
91.143, flight operations conducted by F AA certificated pilots or conducted in aircraft of U.S. registry are prohibited at any
altitude from surface to unlimited, within the following area 30−nautical−mile radius of the Melbourne/MLB/VORTAC 010
degree radial 21−nautical−mile fix. St. Petersburg, Florida/PIE/FSS 813−545−1645 (122.2) is the F AA coordination facility
and should be contacted for the current status of any airspace associated with the space shuttle operations. This airspace
encompasses R2933, R2932, R2931, R2934, R2935, W497A and W158A. Additional warning and restricted areas will be
active in conjunction with the operations. Pilots must consult all NOTAMs regarding this operation.
3−5−4. Parachute Jump Aircraft Operations
a. Procedures relating to parachute jump areas are contained in 14 CFR part 105. Tabulations of parachute
jump areas in the U.S. are contained in the Chart Supplement.
b. Pilots of aircraft engaged in parachute jump operations are reminded that all reported altitudes must be with
reference to mean sea level, or flight level, as a ppropriate, to enable ATC to provide meaningful traffic
information.
c. Parachute operations in the vicinity of an airport without an operating control tower − there is no substitute
for alertness while in the vicinity of an airport. It is essential that pilots conducting parachute operations be alert,
look for other traffic, and exchange traffic information as recommended in paragraph 4−1−9, Traffic Advisory
Practices at Airports Without Operating Control Towers. In addition, pilots should avoid releasing parachutes
while in an airport traffic pattern when there are other aircraft in that pattern. Pilots should make appropriate
broadcasts on the designated Common Traffic Advisory Frequency (CTAF), and monitor that CTAF until all
parachute activity has terminated or the aircraft has left the area. Prior to commencing a jump operation, the pilot
should broadcast the aircraft’s altitude and position in relation to the airport, the approximate relative time when
the jump will commence and terminate, and listen to the position reports of other aircraft in the area.
3−5−5. Published VFR Routes
Published VFR routes for transitioning around, under and through complex airspace such as Class B airspace
were developed through a number of FAA and industry initiatives. All of the following terms, i.e., “VFR Flyway”
Other Airspace Areas 3−5−5
AIM 2/20/25
“VFR Corridor” and “VFR Transition Route” have been used when referring to the same or different types of
routes or airspace. The following paragraphs identify and clarify the functionality of each type of route and
specify where and when an ATC clearance is required.
a. VFR Flyways.
1. A VFR Flyway is defined as a general flight path not defined as a specific course, for use by pilots in
planning flights into, out of, through or near complex terminal airspace to avoid Class B airspace. An ATC
clearance is NOT required to fly these routes.
FIG 3−5−1
VFR Flyway Planning Chart
2. VFR Flyways are depicted on the reverse side of some VFR Terminal Area Charts (TACs ). (See FIG
3−5−1.) These charts identify VFR Flyways designed to help VFR pilots avoid major controlled traffic flows.
They may further depict multiple VFR routings throughout the area which may be used as an alternative to flight
within Class B airspace. The ground references provide a guide for improved visual navigation. These routes are
not intended to discourage requests for VFR operations within Class B airspace but are designed solely to assist
pilots in planning for flights under and around busy Class B airspace without entering ClassB airspace.
3. It is very important to remember that these suggested routes are not sterile of other traffic. The entire
Class B airspace, and the airspace underneath it, may be heavily congested with many different types of aircraft.
3−5−6 Other Airspace Areas
AIM2/20/258/7/25 AIM
Pilot adherence to VFR rules must be exercised at all times. Communications must be established and maintained
between your aircraft and any control tower while transiting Class–C or Class D surface areas of airports under
Class B airspace.
b. VFR Corridors.
1. The design of a few of the first Class B airspace areas provided a corridor for the passage of uncontrolled
traffic. A VFR corridor is defined as airspace through Class B airspace, with defined vertical and lateral
boundaries, in which aircraft may operate without an ATC clearance or communication with air traffic control.
2. These corridors are, in effect, a “hole” through Class B airspace. (See FIG 3−5−2.) A classic example
would be the corridor through the Los Angeles Class B airspace, which has been subsequently changed to Special
Flight Rules airspace (SFR). A corridor is surrounded on all sides by Class B airspace and does not extend down
to the surface like a VFR Flyway. Because of their finite lateral and vertical limits, and the volume of VFR traffic
using a corridor, extreme caution and vigilance must be exercised.
FIG 3−5−2
Class B Airspace
3. Because of the heavy traffic volume and the procedures necessary to efficiently manage the flow of
traffic, it has not been possible to incorporate VFR corridors in the development or modifications of Class B
airspace in recent years.
c. VFR Transition Routes.
1. To accommodate VFR traffic through terminal airspace, VFR Transition Routes were developed. A VFR
Transition Route is defined as a specific flight course depicted and described on a TAC and/or VFR Flyway
Planning Chart. Communication with ATC where the route transitions Class B, Class C, and/or Class D airspace
is required. In addition to communication requirements, a clearance is required to operate in Class B airspace.
VFR Transition Routes may include published altitudes or ATC-assigned altitudes. Per 14 CFR section 91.123,
pilot compliance is expected for all route and altitude restrictions as published or assigned by ATC. VFR
Transition Route and altitude assignments do not relieve pilots from their duty to comply with 14 CFR section
91.119. Pilots are expected to request an alternate clearance if necessary for compliance.
2. These routes, as depicted in FIG 3− 5−3, are designed to show the pilot where to position the aircraft
where an ATC assignment or clearance for the route can normally be expected with minimal or no delay. Until
ATC authorization is received, pilots must remain clear of Class B airspace. On initial contact, pilots should
advise ATC of their position, altitude, route name desired, and direction of flight.
3. For secondary airports underlying or in close proximity to Class B or Class C airspace, VFR Transition
Routes may be developed and depicted for arrivals/departures. These arrivals/departures may be requested from
or assigned by ATC.
Other Airspace Areas 3−5−7
AIM 2/20/253/15/077110.65R CHG 2AIM 1/22/26
FIG 3−5−3
VFR Transition Route
d. Helicopter Route Chart.
1. Helicopter Routes are depicted on a specialized VFR chart established for select high traffic density areas
to enhance helicopter access and ease of operation. The Helicopter Route Chart depicts prominent geographical
features, roads and obstructions. A Helicopter Route is a specific VFR flight course and is depicted on the
Helicopter Route Chart. These routes contain specific altitudes and instructions for navigating over visual
reference points as published, or as instructed by ATC.
2. Helicopter Route Charts, as depicted in FIG 3−5−4, incorporate expanded ground reference and unique
symbology to improve visual navigation. The charts contain additional information such as frequencies to
self−announce on and other route information. On initial contact, pilots should advise ATC of their position,
altitude, and route name desired. Helicopter Routes may include published altitudes or ATC-assigned altitudes.
Per 14 CFR section 91.123, pilot compliance is expected for all route and altitude restrictions as published or
assigned by ATC. Helicopter Route and altitude assignments do not relieve pilots from their duty to comply with
14 CFR section 91.119 and 132.203(b). Pilots are expected to request an alternate clearance if necessary for
compliance.
3. VFR Helicopter routes are available at the following website:
https://www.faa.gov/air_traffic/flight_info/aeronav/digital_products/vfr/.
3−5−8 Other Airspace Areas
AIM2/20/258/7/25 AIM
FIG 3−5−4
Helicopter Route Chart
3−5−6. Terminal Radar Service Area (TRSA)
a. Background. TRSAs were originally established as part of the Terminal Radar Program at selected
airports. TRSAs were never controlled airspace from a regulatory standpoint because the establishment of
TRSAs was never subject to the rulemaking process; consequently, TRSAs are not contained in 14 CFR part 71
nor are there any TRSA operating rules in 14 CFR part 91. Part of the Airport Radar Service Area (ARSA)
program was to eventually replace all TRSAs. However, the ARSA requirements became relatively stringent and
it was subsequently decided that TRSAs would have to meet ARSA criteria before they would be converted.
TRSAs do not fit into any of the U.S. airspace classes; therefore, they will continue to be non−part 71 airspace
areas where participating pilots can receive additional radar services which have been redefined as TRSA
Service.
b. TRSAs. The primary airport(s) within the TRSA become(s) Class D airspace. The remaining portion of
the TRSA overlies other controlled airspace which is normally Class E airspace beginning at 700 or 1,200 feet
and established to transition to/from the en route/terminal environment.
c. Participation. Pilots operating under VFR are encouraged to contact the radar approach control and avail
themselves of the TRSA Services. However, participation is voluntary on the part of the pilot. See Chapter 4,
Air Traffic Control, for details and procedures.
d. Charts. TRSAs are depicted on VFR sectional and terminal area charts with a solid black line and altitudes
for each segment. The Class D portion is charted with a blue segmented line.
Other Airspace Areas 3−5−9
AIM 2/20/25
3−5−7. Special Air Traffic Rules (SATR) and Special Flight Rules Area (SFRA)
a. Background. The Code of Federal Regulations (CFR) prescribes special air traffic rules for aircraft
operating within the boundaries of certain designated airspace. These areas are listed in 14 CFR part 93 and can
be found throughout the NAS. Procedures, nature of operations, configuration, size, and density of traffic vary
among the identified areas.
b. SFRAs. Airspace of defined dimensions, above land areas or territorial waters, within which the flight of
aircraft is subject to the rules set forth in 14 CFR part 93, unless otherwise authorized by air traffic control. Not
all areas listed in 14 CFR part 93 are designated SFRA, but special air traffic rules apply to all areas described
in 14 CFR part 93.
REFERENCE−
14 CFR Part 93, Special Air Traffic Rules
F AA Order JO 7110.65, Para 9−2−10, Special Air Traffic Rules (SATR) and Special Flight Rules Area (SFRA)
P/CG − Special Air Traffic Rules (SATR)
c. Participation. Each person operating an aircraft to, from, or within airspace designated as a SATR area or
SFRA must adhere to the special air traffic rules set forth in 14 CFR part 93, as applicable, unless otherwise
authorized or required by ATC.
d. Charts. SFRAs are depicted on VFR sectional, terminal area, and helicopter route charts. (See FIG 3−5−5.)
FIG 3−5−5
SFRA Boundary
e. Additional information and resources regarding SFRA, including procedures for flight in individual areas,
may be found on the FAA Safety website at http://www.faasafety.gov
3−5−8. Washington, DC, Special Flight Rules Area (SFRA) including the Flight Restricted
Zone (FRZ)
A pilot conducting any type of flight operation in the Washington, DC, SFRA/FRZ must comply with the
requirements in:
a. 14 CFR section 93.339, Washington, DC, Metropolitan Area Special Flight Rules Area including the FRZ.
b. 14 CFR section 91.161, Special Awareness Training for the DC SFRA/FRZ, also located on the FAA
website at https://www.faasafety.gov/.
c. Any 14 CFR section 99.7 special security instructions for the DC SFRA/FRZ published via NOTAM by
FAA in the interest of national security.
3−5−9. Weather Reconnaissance Area (WRA)
a. General. Hurricane Hunters from the United States Air Force Reserve 53 rd Weather Reconnaissance
Squadron (WRS) and the National Oceanic and Atmospheric Administration (NOAA) Aircraft Operations
3−5−10 Other Airspace Areas
AIM2/20/258/7/25 AIM
Center (AOC) operate weather reconnaissance/research aircraft missions, in support of the National Hurricane
Operations Plan (NHOP), to gather meteorological data on hurricanes and tropical cyclones. 53 rd WRS and
NOAA AOC aircraft normally conduct these missions in airspace identified in a published WRA Notice to
Airmen (NOTAM).
b. WRAs. Airspace with defined dimensions and published by a NOTAM, which is established to support
weather reconnaissance/research flights. ATC services are not provided within WRAs. Only participating
weather reconnaissance/research aircraft from the 53rd WRS and NOAA AOC are permitted to operate within
a WRA. A WRA may only be established in airspace within U. S. Flight Information Regions (FIR) outside of
U. S. territorial airspace.
c. A published WRA NOTAM describes the airspace dimensions of the WRA and the expected activities
within the WRA. WRAs may border adjacent foreign FIRs, but are wholly contained within U.S. FIRs. As ATC
services are not provided within a WRA, non−participating aircraft should avoid WRAs, and IFR aircraft should
expect to be rerouted to avoid WRAs.
3−5−10. Other Non− Charted Airspace Areas
a. Stationary or Moving Altitude Reservation (ALTRV). A Stationary or Moving ALTRV is announced via
an airspace NOTAM issued by the Central Altitude Reservation Facility (CARF) or ARTCC. These
announcements will appear in CARF and/or ARTCC NOTAMS. This airspace ensures non−participating IFR
aircraft remain separated from special activity. Non−participating VFR aircraft are permitted to fly through the
area but should exercise vigilance.
b. ATC ASSIGNED AIRSPACE. Airspace of defined vertical/lateral limits, assigned by ATC, for the purpose
of providing air traffic segregation between the specified activities being conducted within the assigned airspace
and other IFR air traffic. ATCAA locations and scheduled activation information can be found on the FAA SUA
website; a NOTAM will not be issued to announce the activation of this airspace.
Other Airspace Areas 3−5−11
AIM2/20/258/7/25 AIM
Chapter 4. Air Traffic Control
Section 1. Services Available to Pilots
4−1−1. Air Route Traffic Control Centers
Centers are established primarily to provide air traffic service to aircraft operating on IFR flight plans within
controlled airspace, and principally during the en route phase of flight.
4−1−2. Control Towers
Towers have been established to provide for a safe, orderly and expeditious flow of traffic on and in the vicinity
of an airport. When the responsibility has been so delegated, towers also provide for the separation of IFR aircraft
in the terminal areas.
REFERENCE−
AIM, Para 5−4−3, Approach Control.
4−1−3. Flight Service Stations
Flight Service Stations (FSSs) are air traffic facilities that provide pilot briefings, flight plan processing, en route
flight advisories, search and rescue services, and assistance to lost aircraft and aircraft in emergency situations.
FSSs also relay ATC clearances, process Notices to Airmen, and broadcast aviation weather and aeronautical
information. In Alaska, designated FSSs also take weather observations, and provide Airport Advisory Services
(AAS).
4−1−4. Recording and Monitoring
a. Calls to air traffic control (ATC) facilities (ARTCCs, Towers, FSSs, Central Flow, and Operations Centers)
over radio and ATC operational telephone lines (lines used for operational purposes such as controller
instructions, briefings, opening and closing flight plans, issuance of IFR clearances and amendments, counter
hijacking activities, etc.) may be monitored and recorded for operational uses such as accident investigations,
accident prevention, search and rescue purposes, specialist training and evaluation, and technical evaluation and
repair of control and communications systems.
b. Where the public access telephone is recorded, a beeper tone is not required. In place of the “beep” tone
the FCC has substituted a mandatory requirement that persons to be recorded be given notice they are to be
recorded and give consent. Notice is given by this entry, consent to record is assumed by the individual placing
a call to the operational facility.
4−1−5. Communications Release of IFR Aircraft Landing at an Airport Without an Operating
Control Tower
Aircraft operating on an IFR flight plan, landing at an airport without an operating control tower will be advised
to change to the airport advisory frequency when direct communications with ATC are no longer required.
Towers and centers do not have nontower airport traffic and runway in use information. The instrument approach
may not be aligned with the runway in use; therefore, if the information has not already been obtained, pilots
should make an expeditious change to the airport advisory frequency when authorized.
REFERENCE−
AIM, Para 5−4−4, Advance Information on Instrument Approach.
4−1−6. Pilot Visits to Air Traffic Facilities
Pilots are encouraged to participate in local pilot/air traffic control outreach activities. However, due to security
and workload concerns, requests for air traffic facility visits may not always be approved. Therefore, visit
Services Available to Pilots 4−1−1
AIM 2/20/25
requests should be submitted through the air traffic facility as early as possible. Pilots should contact the facility
and advise them of the number of persons in the group, the time and date of the proposed visit, and the primary
interest of the group. The air traffic facility will provide further instructions if a request can be approved.
REFERENCE−
F AA Order 1600.69, F AA Facility Security Management Program.
4−1−7. Operation Rain Check
Operation Rain Check is a program designed and managed by local air traffic control facility management. Its
purpose is to familiarize pilots and aspiring pilots with the ATC system, its functions, responsibilities and
benefits.
REFERENCE−
F AA Order JO 7210.3, Para 4−2−2, Pilot Education.
F AA Order 1600.69, F AA Facility Security Management Program.
4−1−8. Approach Control Service for VFR Arriving Aircraft
a. Numerous approach control facilities have established programs for arriving VFR aircraft to contact
approach control for landing information. This information includes: wind, runway, and altimeter setting at the
airport of intended landing. This information may be omitted if contained in the Automatic Terminal Information
Service (ATIS) broadcast and the pilot states the appropriate ATIS code.
NOTE−
Pilot use of “have numbers” does not indicate receipt of the ATIS broadcast. In addition, the controller will provide traffic
advisories on a workload permitting basis.
b. Such information will be furnished upon initial contact with concerned approach control facility. The pilot
will be requested to change to the tower frequency at a predetermined time or point, to receive further landing
information.
c. Where available, use of this procedure will not hinder the operation of VFR flights by requiring excessive
spacing between aircraft or devious routing.
d. Compliance with this procedure is not mandatory but pilot participation is encouraged.
REFERENCE−
AIM, Para 4−1−18, Terminal Radar Services for VFR Aircraft.
NOTE−
Approach control services for VFR aircraft are normally dependent on ATC radar. These services are not available during
periods of a radar outage.
4−1−9. Traffic Advisory Practices at Airports Without Operating Control Towers
(See TBL 4−1−1.)
a. Airport Operations Without Operating Control Tower
1. There is no substitute for alertness while in the vicinity of an airport. It is essential that pilots be alert and
look for other traffic and exchange traffic information when approaching or departing an airport without an
operating control tower. This is of particular importance since other aircraft may not have communication
capability or, in some cases, pilots may not communicate their presence or intentions when operating into or out
of such airports. To achieve the greatest degree of safety, it is essential that:
(a) All radio−equipped aircraft transmit/receive on a common frequency identified for the purpose of
airport advisories; and
(b) Pilots use the correct airport name, as identified in appropriate aeronautical publications, to reduce
the risk of confusion when communicating their position, intentions, and/or exchanging traffic information.
2. An airport may have a full or part-time tower or FSS located on the airport, a full or part-time UNICOM
station or no aeronautical station at all. There are three ways for pilots to communicate their intention and obtain
Services Available to Pilots 4−1−2
2/20/25 AIM
airport/traffic information when operating at an airport that does not have an operating tower: by communicating
with an FSS, a UNICOM operator, or by making a self-announce broadcast.
NOTE−
FSS airport advisories are available only in Alaska.
3. Many airports are now providing completely automated weather, radio check capability and airport
advisory information on an automated UNICOM system. These systems offer a variety of features, typically
selectable by microphone clicks, on the UNICOM frequency. Availability of the automated UNICOM will be
published in the Chart Supplement and approach charts.
b. Communicating on a Common Frequency
1. The key to communicating at an airport without an operating control tower is selection of the correct
common frequency. The acronym CTAF which stands for Common Traffic Advisory Frequency, is synonymous
with this program. A CTAF is a frequency designated for the purpose of carrying out airport advisory practices
while operating to or from an airport without an operating control tower. The CTAF may be a UNICOM,
MULTICOM, FSS, or tower frequency and is identified in appropriate aeronautical publications.
NOTE−
FSS frequencies are available only in Alaska.
Services Available to Pilots 4−1−3
AIM 2/20/25
TBL 4−1−1
Summary of Recommended Communication Procedures
Communication/Broadcast Procedures
Facility at Airport Frequency Use Outbound Inbound
Practice
Instrument
Approach
1. UNICOM (No Tower or
FSS)
Communicate with UNICOM
station on published CTAF
frequency (122.7; 122.8; 122.725;
122.975; or 123.0). If unable to
contact UNICOM station, use
self-announce procedures on
CTAF.
Before taxiing and
before taxiing on
the runway for
departure.
10 miles out.
Entering
downwind, base,
and final. Leaving
the runway.
2. No Tower, FSS, or
UNICOM
Self-announce on MULTICOM
frequency 122.9.
Before taxiing and
before taxiing on
the runway for
departure.
10 miles out.
Entering
downwind, base,
and final. Leaving
the runway.
Departing final
approach fix
(name) or on final
approach segment
inbound.
3. No Tower in operation,
FSS open (Alaska only)
Communicate with FSS on CTAF
frequency.
Before taxiing and
before taxiing on
the runway for
departure.
10 miles out.
Entering
downwind, base,
and final. Leaving
the runway.
Approach com-
pleted/terminated.
4. FSS Closed (No Tower) Self-announce on CTAF. Before taxiing and
before taxiing on
the runway for
departure.
10 miles out.
Entering
downwind, base,
and final. Leaving
the runway.
5. Tower or FSS not in
operation
Self-announce on CTAF. Before taxiing and
before taxiing on
the runway for
departure.
10 miles out.
Entering
downwind, base,
and final. Leaving
the runway.
6. Designated CTAF Area
(Alaska Only)
Self-announce on CTAF
designated on chart or Chart
Supplement Alaska.
Before taxiing and
before taxiing on
the runway for
departure until
leaving designated
area.
When entering
designated CTAF
area.
2. CTAF (Alaska Only). In Alaska, a CTAF may also be designated for the purpose of carrying out
advisory practices while operating in designated areas with a high volume of VFR traffic.
3. The CTAF frequency for a particular airport or area is contained in the Chart Supplement U.S., Chart
Supplement Alaska, Alaska Terminal Publication, Instrument Approach Procedure Charts, and Instrument
Departure Procedure (DP) Charts. Also, the CTAF frequency can be obtained by contacting any FSS. Use of the
appropriate CTAF, combined with a visual alertness and application of the following recommended good
operating practices, will enhance safety of flight into and out of all uncontrolled airports.
c. Recommended Traffic Advisory Practices
1. Pilots of inbound traffic should monitor and communicate as appropriate on the designated CTAF from
10 miles to landing. Pilots of departing aircraft should monitor/communicate on the appropriate frequency from
start-up, during taxi, and until 10 miles from the airport unless the CFRs or local procedures require otherwise.
2. Pilots of aircraft conducting other than arriving or departing operations at altitudes normally used by
arriving and departing aircraft should monitor/communicate on the appropriate frequency while within 10 miles
of the airport unless required to do otherwise by the CFRs or local procedures. Such operations include parachute
jumping/dropping, en route, practicing maneuvers, etc.
Services Available to Pilots 4−1−4
2/20/25 AIM
3. In Alaska, pilots of aircraft conducting other than arriving or departing operations in designated CTAF
areas should monitor/communicate on the appropriate frequency while within the designated area, unless
required to do otherwise by CFRs or local procedures. Such operations include parachute jumping/dropping, en
route, practicing maneuvers, etc.
REFERENCE−
AIM, Para 3−5−4, Parachute Jump Aircraft Operations
d. Airport Advisory/Information Services Provided by a FSS
1. There are two advisory type services provided at selected airports.
(a) Local Airport Advisory (LAA) is available only in Alaska and provided at airports that have a FSS
physically located on the airport, which does not have a control tower or where the tower is operated on a
part−time basis. The CTAF for LAA airports is disseminated in the appropriate aeronautical publications.
(b) Remote Airport Information Service (RAIS) is provided in support of special events at nontowered
airports by request from the airport authority.
2. In communicating with a CTAF FSS, check the airport’s automated weather and establish two −way
communications before transmitting outbound/inbound intentions or information. An inbound aircraft should
initiate contact approximately 10 miles from the airport, reporting aircraft identification and type, altitude,
location relative to the airport, intentions (landing or over flight), possession of the automated weather, and
request airport advisory or airport information service. A departing aircraft should initiate contact before taxiing,
reporting aircraft identification and type, VFR or IFR, location on the airport, intentions, direction of take−off,
possession of the automated weather, and request airport advisory or information service. Also, report intentions
before taxiing onto the active runway for departure. If you must change frequencies for other service after initial
report to FSS, return to FSS frequency for traffic update.
(a) Inbound
EXAMPLE−
Vero Beach radio, Centurion Six Niner Delta Delta is ten miles south, two thousand, landing Vero Beach. I have the
automated weather, request airport advisory.
(b) Outbound
EXAMPLE−
Vero Beach radio, Centurion Six Niner Delta Delta, ready to taxi to runway 22, VFR, departing to the southwest. I have the
automated weather, request airport advisory.
3. Airport advisory service includes wind direction and velocity, favored or designated runway, altimeter
setting, known airborne and ground traffic, NOTAMs, airport taxi routes, airport traffic pattern information, and
instrument approach procedures. These elements are varied so as to best serve the current traffic situation. Some
airport managers have specified that under certain wind or other conditions designated runways be used. Pilots
should advise the FSS of the runway they intend to use.
CAUTION−
All aircraft in the vicinity of an airport may not be in communication with the FSS.
e. Information Provided by Aeronautical Advisory Stations (UNICOM)
1. UNICOM is a nongovernment air/ground radio communication station which may provide airport
information at public use airports where there is no tower or FSS.
2. On pilot request, UNICOM stations may provide pilots with weather information, wind direction, the
recommended runway, or other necessary information. If the UNICOM frequency is designated as the CTAF,
it will be identified in appropriate aeronautical publications.
f. Unavailability of Information from FSS or UNICOM
Should LAA by an FSS or Aeronautical Advisory Station UNICOM be unavailable, wind and weather
information may be obtainable from nearby controlled airports via Automatic Terminal Information Service
(ATIS) or Automated Weather Observing System (AWOS) frequency.
Services Available to Pilots 4−1−5
AIM 2/20/25
g. Self-Announce Position and/or Intentions
1. General. Self-announce is a procedure whereby pilots broadcast their position or intended flight activity
or ground operation on the designated CTAF. This procedure is used primarily at airports which do not have an
FSS on the airport. The self-announce procedure should also be used if a pilot is unable to communicate with
the FSS on the designated CTAF. Pilots stating, “Traffic in the area, please advise” is not a recognized
Self−Announce Position and/or Intention phrase and should not be used under any condition.
2. If an airport has a tower and it is temporarily closed, or operated on a part-time basis and there is no FSS
on the airport or the FSS is closed, use the CTAF to self-announce your position or intentions.
3. Where there is no tower, FSS, or UNICOM station on the airport, use MULTICOM frequency 122.9 for
self-announce procedures. Such airports will be identified in appropriate aeronautical information publications.
4. Straight−in Landings. The FAA discourages VFR straight −in approaches to landings due to the
increased risk of a mid−air collision. However, if a pilot chooses to execute a straight−in approach for landing
without entering the airport traffic pattern, the pilot should self−announce their position on the designated CTAF
approximately 8 to 10 miles from the airport and coordinate their straight−in approach and landing with other
airport traffic. Pilots executing a straight−in approach (IFR or VFR) do not have priority over other aircraft in
the traffic pattern, and must comply with the provisions of 14 CFR 91.113 (g), Right−of−way rules.
5. Traffic Pattern Operations. All traffic within a 10− mile radius of a non −towered airport or a
part−time−towered airport when the control tower is not operating, should monitor and communicate on the
designated CTAF when entering the traffic pattern. Pilots operating in the traffic pattern or on a straight −in
approach must be alert at all times to other aircraft in the pattern, or conducting straight −in approaches, and
communicate their position to avoid a possible traffic conflict. In the airport traffic pattern and while on
straight−in approaches to a runway, effective communication and a pilot’s responsibility to see−and−avoid are
essential mitigations to avoid a possible midair collision. In addition, following established traffic pattern
procedures eliminates excessive maneuvering at low altitudes, reducing the risk of loss of aircraft control.
REFERENCE−
F AA Advisory Circular (AC) 90−66, Non−Towered Airport Flight Operations.
6. Practice Approaches. Pilots conducting practice instrument approaches should be particularly alert for
other aircraft that may be departing in the opposite direction. When conducting any practice approach, regardless
of its direction relative to other airport operations, pilots should make announcements on the CTAF as follows:
(a) Departing the final approach fix, inbound (nonprecision approach) or departing the outer marker or
fix used in lieu of the outer marker, inbound (precision approach);
(b) Established on the final approach segment or immediately upon being released by ATC;
(c) Upon completion or termination of the approach; and
(d) Upon executing the missed approach procedure.
7. Departing aircraft should always be alert for arrival aircraft coming from the opposite direction.
8. Recommended self−announce broadcasts: It should be noted that aircraft operating to or from another
nearby airport may be making self−announce broadcasts on the same UNICOM or MULTICOM frequency. To
help identify one airport from another, the airport name should be spoken at the beginning and end of each
self−announce transmission. When referring to a specific runway, pilots should use the runway number and not
use the phrase “Active Runway.”
(a) Inbound
EXAMPLE−
Strawn traffic, Apache Two Two Five Zulu, (position), (altitude), (descending) or entering downwind/base/final (as
appropriate) runway one seven full stop, touch−and−go, Strawn.
Strawn traffic Apache Two Two Five Zulu clear of runway one seven Strawn.
(b) Outbound
Services Available to Pilots 4−1−6
2/20/25 AIM
EXAMPLE−
Strawn traffic, Queen Air Seven One Five Five Bravo (location on airport) taxiing to runway two six Strawn.
Strawn traffic, Queen Air Seven One Five Five Bravo departing runway two six. Departing the pattern to the (direction),
climbing to (altitude) Strawn.
(c) Practice Instrument Approach
EXAMPLE−
Strawn traffic, Cessna Two One Four Three Quebec (position from airport) inbound descending through (altitude) practice
(name of approach) approach runway three five Strawn.
Strawn traffic, Cessna Two One Four Three Quebec practice (type) approach completed or terminated runway three five
Strawn.
h. UNICOM Communications Procedures
1. In communicating with a UNICOM station, the following practices will help reduce frequency
congestion, facilitate a better understanding of pilot intentions, help identify the location of aircraft in the traffic
pattern, and enhance safety of flight:
(a) Select the correct UNICOM frequency.
(b) State the identification of the UNICOM station you are calling in each transmission.
(c) Speak slowly and distinctly.
(d) Report approximately 10 miles from the airport, reporting altitude, and state your aircraft type,
aircraft identification, location relative to the airport, state whether landing or overflight, and request wind
information and runway in use.
(e) Report on downwind, base, and final approach.
(f) Report leaving the runway.
2. Recommended UNICOM phraseologies:
(a) Inbound
PHRASEOLOGY−
FREDERICK UNICOM CESSNA EIGHT ZERO ONE TANGO FOXTROT 10 MILES SOUTHEAST DESCENDING
THROUGH (altitude) LANDING FREDERICK, REQUEST WIND AND RUNWAY INFORMATION FREDERICK.
FREDERICK TRAFFIC CESSNA EIGHT ZERO ONE TANGO FOXTROT ENTERING DOWNWIND/BASE/ FINAL (as
appropriate) FOR RUNWAY ONE NINER (full stop/touch−and−go) FREDERICK.
FREDERICK TRAFFIC CESSNA EIGHT ZERO ONE TANGO FOXTROT CLEAR OF RUNWAY ONE NINER
FREDERICK.
(b) Outbound
PHRASEOLOGY−
FREDERICK UNICOM CESSNA EIGHT ZERO ONE TANGO FOXTROT (location on airport) TAXIING TO RUNWAY
ONE NINER, REQUEST WIND AND TRAFFIC INFORMATION FREDERICK.
FREDERICK TRAFFIC CESSNA EIGHT ZERO ONE TANG O FOXTROT DEP ARTING RUNWAY ONE NINER.
“REMAINING IN THE P ATTERN” OR “DEP ARTING THE P ATTERN TO THE (direction) (as appropriate)”
FREDERICK.
4−1−10. IFR Approaches/Ground Vehicle Operations
a. IFR Approaches. When operating in accordance with an IFR clearance and ATC approves a change to
the advisory frequency, make an expeditious change to the CTAF and employ the recommended traffic advisory
procedures.
b. Ground Vehicle Operation. Airport ground vehicles equipped with radios should monitor the CTAF
frequency when operating on the airport movement area and remain clear of runways/taxiways being used by
aircraft. Radio transmissions from ground vehicles should be confined to safety-related matters.
Services Available to Pilots 4−1−7
AIM 2/20/25
c. Radio Control of Airport Lighting Systems. Whenever possible, the CTAF will be used to control airport
lighting systems at airports without operating control towers. This eliminates the need for pilots to change
frequencies to turn the lights on and allows a continuous listening watch on a single frequency. The CTAF is
published on the instrument approach chart and in other appropriate aeronautical information publications.
4−1−11. Designated UNICOM/MULTICOM Frequencies
Frequency use
a. The following listing depicts UNICOM and MULTICOM frequency uses as designated by the Federal
Communications Commission (FCC). (See TBL 4−1−2.)
TBL 4−1−2
Unicom/Multicom Frequency Usage
Use Frequency
Airports without an operating control tower. 122.700
122.725
122.800
122.975
123.000
123.050
123.075
(MULTICOM FREQUENCY) Activities of a
temporary, seasonal, emergency nature or
search and rescue, as well as, airports with no
tower, FSS, or UNICOM.
122.900
(MULTICOM FREQUENCY) Forestry
management and fire suppression, fish and
game management and protection, and
environmental monitoring and protection.
122.925
Airports with a control tower or FSS on airport. 122.950
NOTE−
1. In some areas of the country, frequency interference may be encountered from nearby airports using the same UNICOM
frequency. Where there is a problem, UNICOM operators are encouraged to develop a “least interference” frequency
assignment plan for airports concerned using the frequencies designated for airports without operating control towers.
UNICOM licensees are encouraged to apply for UNICOM 25 kHz spaced channel frequencies. Due to the extremely limited
number of frequencies with 50 kHz channel spacing, 25 kHz channel spacing should be implemented. UNICOM licensees
may then request FCC to assign frequencies in accordance with the plan, which FCC will review and consider for approval.
2. Wind direction and runway information may not be available on UNICOM frequency 122.950.
b. The following listing depicts other frequency us es as designated by the Federal Communications
Commission (FCC). (See TBL 4−1−3.)
Services Available to Pilots 4−1−8
2/20/25 AIM
TBL 4−1−3
Other Frequency Usage Designated by FCC
Use Frequency
Air-to-air communication
(private fixed wing aircraft).
122.750
Helicopter air−to−air communications; air
traffic control operations.
123.025
Aviation instruction, Glider, Hot Air Balloon
(not to be used for advisory service).
123.300
123.500
Assignment to flight test land and aircraft stations
(not for air−to−air communication except for
those aircraft operating in an oceanic FIR).
123.4001
123.4502
1This frequency is available only to itinerant stations that have a requirement to be periodically transferred to various
locations.
2Mobile station operations on these frequencies are limited to an area within 320 km (200 mi) of an associated flight test
land station.
4−1−12. Use of UNICOM for ATC Purposes
UNICOM service may be used for ATC purposes, only under the following circumstances:
a. Revision to proposed departure time.
b. Takeoff, arrival, or flight plan cancellation time.
c. ATC clearance, provided arrangements are made between the ATC facility and the UNICOM licensee to
handle such messages.
4−1−13. Automatic Terminal Information Service (ATIS)
a. ATIS is the continuous broadcast of recorded noncontrol information in selected high activity terminal
areas. Its purpose is to improve controller effectiveness and to relieve frequency congestion by automating the
repetitive transmission of essential but routine information. The information is continuously broadcast over a
discrete VHF radio frequency or the voice portion of a local NA V AID. Arrival ATIS transmissions on a discrete
VHF radio frequency are engineered according to the individual facility requirements, which would normally
be a protected service volume of 20 NM to 60 NM from the ATIS site and a maximum altitude of 25,000 feet
AGL. In the case of a departure ATIS, the protected service volume cannot exceed 5 NM and 100 feet AGL. At
most locations, ATIS signals may be received on the surface of the airport, but local conditions may limit the
maximum ATIS reception distance and/or altitude. Pilots are urged to cooperate in the ATIS program as it relieves
frequency congestion on approach control, ground control, and local control frequencies. The Chart Supplement
indicates airports for which ATIS is provided.
b. ATIS information includes:
1. Airport/facility name
2. Phonetic letter code
3. Time of the latest weather sequence (UTC)
4. Weather information consisting of:
(a) Wind direction and velocity
(b) Visibility
(c) Obstructions to vision
Services Available to Pilots 4−1−9
AIM 2/20/25
(d) Present weather consisting of: sky condition, temperature, dew point, altimeter, a density altitude
advisory when appropriate, and other pertinent remarks included in the official weather observation
5. Instrument approach and runway in use.
The ceiling/sky condition, visibility, and obstructions to vision may be omitted from the ATIS broadcast if the
ceiling is above 5,000 feet and the visibility is more than 5 miles. The departure runway will only be given if
different from the landing runway except at locations having a separate ATIS for departure. The broadcast may
include the appropriate frequency and instructions for VFR arrivals to make initial contact with approach control.
Pilots of aircraft arriving or departing the terminal area can receive the continuous ATIS broadcast at times when
cockpit duties are least pressing and listen to as many repeats as desired. ATIS broadcast must be updated upon
the receipt of any official hourly and special weather. A new recording will also be made when there is a change
in other pertinent data such as runway change, instrument approach in use, etc.
EXAMPLE−
Dulles International information Sierra. One four zero zero zulu. Wind three five zero at eight. Visibility one zero. Ceiling
four thousand five hundred broken. Temperature three four. Dew point two eight. Altimeter three zero one zero. ILS runway
one right approach in use. Departing runway three zero. Advise on initial contact you have information sierra.
c. Pilots should listen to ATIS broadcasts whenever ATIS is in operation.
d. Pilots should notify controllers on initial contact that they have received the ATIS broadcast by repeating
the alphabetical code word appended to the broadcast.
EXAMPLE−
“Information Sierra received.”
e. When a pilot acknowledges receipt of the ATIS broadcast, controllers may omit those items contained in
the broadcast if they are current. Rapidly changing conditions will be issued by ATC and the ATIS will contain
words as follows:
EXAMPLE−
“Latest ceiling/visibility/altimeter/wind/(other conditions) will be issued by approach control/tower .”
NOTE−
The absence of a sky condition or ceiling and/or visibility on ATIS indicates a sky condition or ceiling of 5,000 feet or above
and visibility of 5 miles or more. A remark may be made on the broadcast, “the weather is better than 5000 and 5,” or the
existing weather may be broadcast.
f. Controllers will issue pertinent information to pilots who do not acknowledge receipt of a broadcast or who
acknowledge receipt of a broadcast which is not current.
g. To serve frequency limited aircraft, FSSs are equipped to transmit on the omnirange frequency at most en
route VORs used as ATIS voice outlets. Such communication interrupts the ATIS broadcast. Pilots of aircraft
equipped to receive on other FSS frequencies are encouraged to do so in order that these override transmissions
may be kept to an absolute minimum.
h. While it is a good operating practice for pilots to make use of the ATIS broadcast where it is available, some
pilots use the phrase “have numbers” in communications with the control tower. Use of this phrase means that
the pilot has received wind, runway, and altimeter information ONLY and the tower does not have to repeat this
information. It does not indicate receipt of the ATIS broadcast and should never be used for this purpose.
4−1−14. Automatic Flight Information Service (AFIS) − Alaska FSSs Only
a. AFIS is the continuous broadcast of recorded non−control information at airports in Alaska where an FSS
provides local airport advisory service. Its purpose is to improve FSS specialist efficiency by reducing frequency
congestion on the local airport advisory frequency.
1. The AFIS broadcast will automate the repetitive transmission of essential but routine information (for
example, weather, favored runway, braking action, airport NOTAMs, etc.). The information is continuously
broadcast over a discrete VHF radio frequency (usually the ASOS frequency).
Services Available to Pilots 4−1−10
AIM2/20/258/7/25 AIM
2. Use of AFIS is not mandatory, but pilots who choose to utilize two−way radio communications with the
FSS are urged to listen to AFIS, as it relieves frequency congestion on the local airport advisory frequency. AFIS
broadcasts are updated upon receipt of any official hourly and special weather, and changes in other pertinent
data.
3. When a pilot acknowledges receipt of the AFIS br oadcast, FSS specialists may omit those items
contained in the broadcast if they are current. When rapidly changing conditions exist, the latest ceiling,
visibility, altimeter, wind or other conditions may be omitted from the AFIS and will be issued by the FSS
specialist on the appropriate radio frequency.
EXAMPLE−
“Kotzebue information ALPHA. One six five five zulu. Wind, two one zero at five; visibility two, fog; ceiling one hundred
overcast; temperature minus one two, dew point minus one four; altimeter three one zero five. Altimeter in excess of three
one zero zero, high pressure altimeter setting procedures are in effect. Favored runway two six. Weather in Kotzebue surface
area is below V−F−R minima − an ATC clearance is required. Contact Kotzebue Radio on 123.6 for traffic advisories and
advise intentions. Notice to Airmen, Hotham NDB out of service. Transcribed Weather Broadcast out of service. Advise on
initial contact you have ALPHA.”
NOTE−
The absence of a sky condition or ceiling and/or visibility on Alaska FSS AFIS indicates a sky condition or ceiling of 5,000
feet or above and visibility of 5 miles or more. A remark may be made on the broadcast, “the weather is better than 5000
and 5.”
b. Pilots should listen to Alaska FSSs AFIS broadcasts whenever Alaska FSSs AFIS is in operation.
NOTE−
Some Alaska FSSs are open part time and/or seasonally.
c. Pilots should notify controllers on initial contact that they have received the Alaska FSSs AFIS broadcast
by repeating the phonetic alphabetic letter appended to the broadcast.
EXAMPLE−
“Information Alpha received.”
d. While it is a good operating practice for pilots to make use of the Alaska FSS AFIS broadcast where it is
available, some pilots use the phrase “have numbers” in communications with the FSS. Use of this phrase means
that the pilot has received wind, runway, and altimeter information ONLY and the Alaska FSS does not have to
repeat this information. It does not indicate receipt of the AFIS broadcast and should never be used for this
purpose.
4−1−15. Radar Traffic Information Service
This is a service provided by radar ATC facilities. Pilots receiving this service are advised of any radar target
observed on the radar display which may be in such proximity to the position of their aircraft or its intended route
of flight that it warrants their attention. This service is not intended to relieve the pilot of the responsibility for
continual vigilance to see and avoid other aircraft.
a. Purpose of the Service
1. The issuance of traffic information as observed on a radar display is based on the principle of assisting
and advising a pilot that a particular radar target’s position and track indicates it may intersect or pass in such
proximity to that pilot’s intended flight path that it warrants attention. This is to alert the pilot to the traffic, to
be on the lookout for it, and thereby be in a better position to take appropriate action should the need arise.
2. Pilots are reminded that the surveillance radar used by ATC does not provide altitude information unless
the aircraft is equipped with Mode C and the radar facility is capable of displaying altitude information.
b. Provisions of the Service
1. Many factors, such as limitations of the radar, volume of traffic, controller workload and communications
frequency congestion, could prevent the controller from providing this service. Controllers possess complete
discretion for determining whether they are able to provide or continue to provide this service in a specific case.
Services Available to Pilots 4−1−11
AIM 2/20/25
The controller’s reason against providing or continuing to provide the service in a particular case is not subject
to question nor need it be communicated to the pilot. In other words, the provision of this service is entirely
dependent upon whether controllers believe they are in a position to provide it. Traffic information is routinely
provided to all aircraft operating on IFR flight plans except when the pilot declines the service, or the pilot is
operating within Class A airspace. Traffic information may be provided to flights not operating on IFR flight
plans when requested by pilots of such flights.
NOTE−
Radar ATC facilities normally display and monitor both primary and secondary radar as well as ADS −B, except that
secondary radar or ADS−B may be used as the sole display source in Class A airspace, and under some circumstances
outside of Class A airspace (beyond primary coverage and in en route areas where only secondary and/or ADS −B is
available). Secondary radar and/or ADS−B may also be used outside Class A airspace as the sole display source when the
primary radar is temporarily unusable or out of service. Pilots in contact with the affected ATC facility are normally advised
when a temporary outage occurs; i.e., “primary radar out of service; traffic advisories available on transponder or ADS−B
aircraft only.” This means simply that only aircraft that have transponders and ADS−B installed and in use will be depicted
on ATC displays when the primary and/or secondary radar is temporarily out of service.
2. When receiving VFR radar advisory service, pilots should monitor the assigned frequency at all times.
This is to preclude controllers’ concern for radio failure or emergency assistance to aircraft under the controller’s
jurisdiction. VFR radar advisory service does not include vectors away from conflicting traffic unless requested
by the pilot. When advisory service is no longer desired, advise the controller before changing frequencies and
then change your transponder code to 1200, if applicable. Pilots should also inform the controller when changing
VFR cruising altitude. Except in programs where radar service is automatically terminated, the controller will
advise the aircraft when radar is terminated.
NOTE−
Participation by VFR pilots in formal programs implemented at certain terminal locations constitutes pilot request. This
also applies to participating pilots at those locations where arriving VFR flights are encouraged to make their first contact
with the tower on the approach control frequency.
c. Issuance of Traffic Information. Traffic information will include the following concerning a target
which may constitute traffic for an aircraft that is:
1. Radar identified
(a) Azimuth from the aircraft in terms of the 12 hour clock, or
(b) When rapidly maneuvering civil test or military aircraft prevent accurate issuance of traffic as in (a)
above, specify the direction from an aircraft’s position in terms of the eight cardinal compass points (N, NE, E,
SE, S, SW, W, NW). This method must be terminated at the pilot’s request.
(c) Distance from the aircraft in nautical miles;
(d) Direction in which the target is proceeding; and
(e) Type of aircraft and altitude if known.
EXAMPLE−
Traffic 10 o’clock, 3 miles, west-bound (type aircraft and altitude, if known, of the observed traffic). The altitude may be
known, by means of Mode C, but not verified with the pilot for accuracy. (To be valid for separation purposes by ATC, the
accuracy of Mode C readouts must be verified. This is usually accomplished upon initial entry into the radar system by a
comparison of the readout to pilot stated altitude, or the field elevation in the case of continuous readout being received from
an aircraft on the airport.) When necessary to issue traffic advisories containing unverified altitude information, the
controller will issue the indicated altitude of the aircraft. The pilot may upon receipt of traffic information, request a vector
(heading) to avoid such traffic. The vector will be provided to the extent possible as determined by the controller provided
the aircraft to be vectored is within the airspace under the jurisdiction of the controller .
2. Not radar identified
(a) Distance and direction with respect to a fix;
(b) Direction in which the target is proceeding; and
Services Available to Pilots 4−1−12
2/20/25 AIM
(c) Type of aircraft and altitude if known.
EXAMPLE−
Traffic 8 miles south of the airport northeast−bound, (type aircraft and altitude if known).
d. The examples depicted in the following figures point out the possible error in the position of this traffic
when it is necessary for a pilot to apply drift correction to maintain this track. This error could also occur in the
event a change in course is made at the time radar traffic information is issued.
FIG 4−1−1
Induced Error in Position of Traffic
WIND
TRACK TRACK
(A) (B)
EXAMPLE−
In FIG 4−1−1 traffic information would be issued to the pilot of aircraft “A” as 12 o’clock. The actual position of the traffic
as seen by the pilot of aircraft “A” would be 2 o’clock. Traffic information issued to aircraft “B” would also be given as
12 o’clock, but in this case, the pilot of “B” would see the traffic at 10 o’clock.
FIG 4−1−2
Induced Error in Position of Traffic
TRACK
(C)
(D)
WIND TRACK
EXAMPLE−
In FIG 4−1−2 traffic information would be issued to the pilot of aircraft “C” as 2 o’clock. The actual position of the traffic
as seen by the pilot of aircraft “C” would be 3 o’clock. Traffic information issued to aircraft “D” would be at an 11 o’clock
position. Since it is not necessary for the pilot of aircraft “D” to apply wind correction (crab) to remain on track, the actual
position of the traffic issued would be correct. Since the radar controller can only observe aircraft track (course) on the radar
display, traffic advisories are issued accordingly, and pilots should give due consideration to this fact when looking for
reported traffic.
4−1−16. Safety Alert
A safety alert will be issued to pilots of aircraft being controlled by ATC if the controller is aware the aircraft
is at an altitude which, in the controller’s judgment, places the aircraft in unsafe proximity to terrain, obstructions
or other aircraft. The provision of this service is contingent upon the capability of the controller to have an
awareness of a situation involving unsafe proximity to terrain, obstructions and uncontrolled aircraft. The
issuance of a safety alert cannot be mandated, but it can be expected on a reasonable, though intermittent basis.
Once the alert is issued, it is solely the pilot’s prerogative to determine what course of action, if any, to take. This
procedure is intended for use in time critical situations where aircraft safety is in question. Noncritical situations
should be handled via the normal traffic alert procedures.
a. Terrain or Obstruction Alert
1. Controllers will immediately issue an alert to the pilot of an aircraft under their control when they
recognize that the aircraft is at an altitude which, in their judgment, may be in an unsafe proximity to
Services Available to Pilots 4−1−13
AIM 2/20/25
terrain/obstructions. The primary method of detecting unsafe proximity is through Mode C automatic altitude
reports.
EXAMPLE−
Low altitude alert Cessna Three Four Juliett, check your altitude immediately. And if the aircraft is not yet on final approach,
the MVA (MEA/MIA/MOCA) in your area is six thousand.
2. Most En Route and Terminal radar facilities have an automated function which, if operating, alerts
controllers when a tracked Mode C equipped aircraft under their control is below or is predicted to be below a
predetermined minimum safe altitude. This function, called Minimum Safe Altitude Warning (MSAW), is
designed solely as a controller aid in detecting potentially unsafe aircraft proximity to terrain/obstructions. The
radar facility will, when MSAW is operating, provide MSAW monitoring for all aircraft with an operating Mode
C altitude encoding transponder that are tracked by the system and are:
(a) Operating on an IFR flight plan; or
(b) Operating VFR and have requested MSAW monitoring.
NOTE−
Pilots operating VFR may request MSAW monitoring if their aircraft are equipped with Mode C transponders.
EXAMPLE−
Apache Three Three Papa request MSAW monitoring.
3. Due to the lack of terrain and obstacle clearance data, accurate automation databases may not be available
for providing MSAW information to aircraft overflying Mexico and Canada. Air traffic facilities along the
United States/Mexico/Canada borders may have MSAW computer processing inhibited where accurate terrain
data is not available.
b. Aircraft Conflict Alert.
1. Controllers will immediately issue an alert to the pilot of an aircraft under their control if they are aware
of another aircraft which is not under their control, at an altitude which, in the controller’s judgment, places both
aircraft in unsafe proximity to each other. With the alert, when feasible, the controller will offer the pilot the
position of the traffic if time permits and an alternate course(s) of action. Any alternate course(s) of action the
controller may recommend to the pilot will be predicated only on other traffic being worked by the controller.
EXAMPLE−
American Three, traffic alert, (position of traffic, if time permits), advise you turn right/left heading (degrees) and/or
climb/descend to (altitude) immediately.
4−1−17. Radar Assistance to VFR Aircraft
a. Radar equipped FAA ATC facilities provide radar assistance and navigation service (vectors) to VFR
aircraft provided the aircraft can communicate with the facility, are within radar coverage, and can be radar
identified.
b. Pilots should clearly understand that authorization to proceed in accordance with such radar navigational
assistance does not constitute authorization for the pilot to violate CFRs. In effect, assistance provided is on the
basis that navigational guidance information issued is advisory in nature and the job of flying the aircraft safely,
remains with the pilot.
c. In many cases, controllers will be unable to determine if flight into instrument conditions will result from
their instructions. To avoid possible hazards resulting from being vectored into IFR conditions, pilots should
keep controllers advised of the weather conditions in which they are operating and along the course ahead.
d. Radar navigation assistance (vectors) may be initiated by the controller when one of the following
conditions exist:
1. The controller suggests the vector and the pilot concurs.
2. A special program has been established and vectoring service has been advertised.
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3. In the controller’s judgment the vector is necessary for air safety.
e. Radar navigation assistance (vectors) and other radar derived information may be provided in response to
pilot requests. Many factors, such as limitations of radar, volume of traffic, communications frequency,
congestion, and controller workload could prevent the controller from providing it. Controllers have complete
discretion for determining if they are able to provide the service in a particular case. Their decision not to provide
the service in a particular case is not subject to question.
4−1−18. Terminal Radar Services for VFR Aircraft
a. Basic Radar Service:
1. In addition to the use of radar for the control of IFR aircraft, all commissioned radar facilities provide
the following basic radar services for VFR aircraft:
(a) Safety alerts.
(b) Traffic advisories.
(c) Limited radar vectoring (on a workload permitting basis).
(d) Sequencing at locations where procedures have been established for this purpose and/or when
covered by a Letter of Agreement.
NOTE−
When the stage services were developed, two basic radar services (traffic advisories and limited vectoring) were identified
as “Stage I.” This definition became unnecessary and the term “Stage I” was eliminated from use. The term “Stage II” has
been eliminated in conjunction with the airspace reclassification, and sequencing services to locations with local procedures
and/or letters of agreement to provide this service have been included in basic services to VFR aircraft. These basic services
will still be provided by all terminal radar facilities whether they include Class B, Class C, Class D or Class E airspace.
“Stage III” services have been replaced with “Class B” and “TRSA” service where applicable.
2. Vectoring service may be provided when requested by the pilot or with pilot concurrence when suggested
by ATC.
3. Pilots of arriving aircraft should contact approach control on the publicized frequency and give their
position, altitude, aircraft call sign, type aircraft, radar beacon code (if transponder equipped), destination, and
request traffic information.
4. Approach control will issue wind and runway, except when the pilot states “have numbers” or this
information is contained in the ATIS broadcast and the pilot states that the current ATIS information has been
received. Traffic information is provided on a workload permitting basis. Approach control will specify the time
or place at which the pilot is to contact the tower on local control frequency for further landing information. Radar
service is automatically terminated and the aircraft need not be advised of termination when an arriving VFR
aircraft receiving radar services to a tower−controlled airport where basic radar service is provided has landed,
or to all other airports, is instructed to change to tower or advisory frequency. (See FAA Order JO 7110.65, Air
Traffic Control, paragraph 5−1−9, Radar Service Termination.)
5. Sequencing for VFR aircraft is available at certain terminal locations (see locations listed in the Chart
Supplement). The purpose of the service is to adjust the flow of arriving VFR and IFR aircraft into the traffic
pattern in a safe and orderly manner and to provide radar traffic information to departing VFR aircraft. Pilot
participation is urged but is not mandatory. Traffic information is provided on a workload permitting basis.
Standard radar separation between VFR or between VFR and IFR aircraft is not provided.
(a) Pilots of arriving VFR aircraft should initiate radio contact on the publicized frequency with approach
control when approximately 25 miles from the airport at which sequencing services are being provided. On initial
contact by VFR aircraft, approach control will assume that sequencing service is requested. After radar contact
is established, the pilot may use pilot navigation to enter the traffic pattern or, depending on traffic conditions,
approach control may provide the pilot with routings or vectors necessary for proper sequencing with other
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participating VFR and IFR traffic en route to the airport. When a flight is positioned behind a preceding aircraft
and the pilot reports having that aircraft in sight, the pilot will be instructed to follow the preceding aircraft. THE
ATC INSTRUCTION TO FOLLOW THE PRECEDING AIRCRAFT DOES NOT AUTHORIZE THE PILOT
TO COMPLY WITH ANY ATC CLEARANCE OR IN STRUCTION ISSUED TO THE PRECEDING
AIRCRAFT. If other “nonparticipating” or “local” aircraft are in the traffic pattern, the tower will issue a landing
sequence. If an arriving aircraft does not want radar service, the pilot should state “NEGATIVE RADAR
SERVICE” or make a similar comment, on initial contact with approach control.
(b) Pilots of departing VFR aircraft are encouraged to request radar traffic information by notifying
ground control, or where applicable, clearance delivery, on initial contact with their request and proposed
direction of flight.
EXAMPLE−
Xray ground control, November One Eight Six, Cessna One Seventy Two, ready to taxi, VFR southbound at 2,500, have
information bravo and request radar traffic information.
NOTE−
Following takeoff, the tower will advise when to contact departure control.
(c) Pilots of aircraft transiting the area and in radar contact/communication with approach control will
receive traffic information on a controller workload permitting basis. Pilots of such aircraft should give their
position, altitude, aircraft call sign, aircraft type, radar beacon code (if transponder equipped), destination, and/or
route of flight.
b. TRSA Service (Radar Sequencing and Separation Service for VFR Aircraft in a TRSA).
1. This service has been implemented at certain terminal locations. The service is advertised in the Chart
Supplement. The purpose of this service is to provide separation between all participating VFR aircraft and all
IFR aircraft operating within the airspace defined as the Terminal Radar Service Area (TRSA). Pilot participation
is urged but is not mandatory.
2. If any aircraft does not want the service, the pilot should state “NEGATIVE TRSA SERVICE” or make
a similar comment, on initial contact with approach control or ground control, as appropriate.
3. TRSAs are depicted on sectional aeronautical charts and listed in the Chart Supplement.
4. While operating within a TRSA, pilots are provided TRSA service and separation as prescribed in this
paragraph. In the event of a radar outage, separation and sequencing of VFR aircraft will be suspended as this
service is dependent on radar. The pilot will be advised that the service is not available and issued wind, runway
information, and the time or place to contact the tower. Traffic information will be provided on a workload
permitting basis.
5. Visual separation is used when prevailing conditions permit and it will be applied as follows:
(a) When a VFR flight is positioned behind a preceding aircraft and the pilot reports having that aircraft
in sight, the pilot will be instructed by A TC to follow the preceding aircraft. Radar service will be continued to
the runway. THE ATC INSTRUCTION TO FOLLOW THE PRECEDING AIRCRAFT DOES NOT
AUTHORIZE THE PILOT TO COMPLY WITH ANY ATC CLEARANCE OR INSTRUCTION ISSUED TO
THE PRECEDING AIRCRAFT.
(b) If other “nonparticipating” or “local” aircraft are in the traffic pattern, the tower will issue a landing
sequence.
(c) Departing VFR aircraft may be asked if they can visually follow a preceding departure out of the
TRSA. The pilot will be instructed to follow the other aircraft provided that the pilot can maintain visual contact
with that aircraft.
6. Participating VFR aircraft will be separated from IFR and other participating VFR aircraft by one of the
following:
(a) 500 feet vertical separation.
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(b) Visual separation.
(c) Target resolution (a process to ensure that correlated radar targets do not touch).
7. Participating pilots operating VFR in a TRSA:
(a) Must maintain an altitude when assigned by ATC unless the altitude assignment is to maintain at or
below a specified altitude. ATC may assign altitudes for separation that do not conform to 14 CFR
section 91.159. When the altitude assignment is no longer needed for separation or when leaving the TRSA, the
instruction will be broadcast, “RESUME APPROPRIATE VFR ALTITUDES.” Pilots must then return to an
altitude that conforms to 14 CFR section 91.159 as soon as practicable.
(b) When not assigned an altitude, the pilot should coordinate with ATC prior to any altitude change.
8. Within the TRSA, traffic information on observed but unidentified targets will, to the extent possible,
be provided to all IFR and participating VFR aircraft. The pilot will be vectored upon request to avoid the
observed traffic, provided the aircraft to be vectored is within the airspace under the jurisdiction of the controller.
9. Departing aircraft should inform ATC of their intended destination and/or route of flight and proposed
cruising altitude.
10. ATC will normally advise participating VFR aircraft when leaving the geographical limits of the TRSA.
Radar service is not automatically terminated with this advisory unless specifically stated by the controller.
c. Class C Service. This service provides, in addition to basic radar service, approved separation between
IFR and VFR aircraft, and sequencing of VFR arrivals to the primary airport.
d. Class B Service. This service provides, in addition to basic radar service, approved separation of aircraft
based on IFR, VFR, and/or weight, and sequencing of VFR arrivals to the primary airport(s).
e. PILOT RESPONSIBILITY. THESE SERVICES ARE NOT TO BE INTERPRETED AS RELIEVING
PILOTS OF THEIR RESPONSIBILITIES TO SEE AND AVOID OTHER TRAFFIC OPERATING IN BASIC
VFR WEATHER CONDITIONS, TO ADJUST THEIR OPERATIONS AND FLIGHT PATH AS
NECESSARY TO PRECLUDE SERIOUS WAKE ENCOUNTERS, TO MAINTAIN APPROPRIATE
TERRAIN AND OBSTRUCTION CLEARANCE, OR TO REMAIN IN WEATHER CONDITIONS EQUAL
TO OR BETTER THAN THE MINIMUMS REQUI RED BY 14 CFR SECTION 91.155. WHENEVER
COMPLIANCE WITH AN ASSIGNED ROUTE, HE ADING AND/OR ALTITUDE IS LIKELY TO
COMPROMISE PILOT RESPONSIBILITY RESPE CTING TERRAIN AND OBSTRUCTION CLEAR -
ANCE, VORTEX EXPOSURE, AND WEATHER MINIMUMS, APPROACH CONTROL SHOULD BE SO
ADVISED AND A REVISED CLEARANCE OR INSTRUCTION OBTAINED.
f. ATC services for VFR aircraft participating in terminal radar services are dependent on ATC radar. Services
for VFR aircraft are not available during periods of a radar outage. The pilot will be advised when VFR services
are limited or not available.
NOTE−
Class B and Class C airspace are areas of regulated airspace. The absence of ATC radar does not negate the requirement
of an ATC clearance to enter Class B airspace or two way radio contact with ATC to enter Class C airspace.
4−1−19. Tower En Route Control (TEC)
a. TEC is an A TC program to provide a service to aircraft proceeding to and from metropolitan areas. It links
designated Approach Control Areas by a network of identified routes made up of the existing airway structure
of the National Airspace System. The FAA initiated an expanded TEC program to include as many facilities as
possible. The program’s intent is to provide an overflow resource in the low altitude system which would enhance
ATC services. A few facilities have historically allowed turbojets to proceed between certain city pairs, such as
Milwaukee and Chicago, via tower en route and these locations may continue this service. However, the
expanded TEC program will be applied, generally, for nonturbojet aircraft operating at and below 10,000 feet.
The program is entirely within the approach control airspace of multiple terminal facilities. Essentially, it is for
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relatively short flights. Participating pilots are encouraged to use TEC for flights of two hours duration or less.
If longer flights are planned, extensive coordination may be required within the multiple complex which could
result in unanticipated delays.
b. Pilots requesting TEC are subject to the same delay factor at the destination airport as other aircraft in the
ATC system. In addition, departure and en route delays may occur depending upon individual facility workload.
When a major metropolitan airport is incurring significant delays, pilots in the TEC program may want to
consider an alternative airport experiencing no delay.
c. There are no unique requirements upon pilots to use the TEC program. Normal flight plan filing procedures
will ensure proper flight plan processing. Pilots should include the acronym “TEC” in the remarks section of the
flight plan when requesting tower en route control.
d. All approach controls in the system may not operate up to the maximum TEC altitude of 10,000 feet. IFR
flight may be planned to any satellite airport in proximity to the major primary airport via the same routing.
4−1−20. Transponder and ADS−B Out Operation
a. General
1. Pilots should be aware that proper application of transponder and ADS −B operating procedures will
provide both VFR and IFR aircraft with a higher degree of safety while operating on the ground and airborne.
Transponder/ADS−B panel designs differ; therefore, a pilot should be thoroughly familiar with the operation of
their particular equipment to maximize its full potential. ADS−B Out, and transponders with altitude reporting
mode turned ON (Mode C or S), substantially increase the capability of surveillance systems to see an aircraft.
This provides air traffic controllers, as well as pilots of suitably equipped aircraft (TCAS and ADS −B In),
increased situational awareness and the ability to identify potential traffic conflicts. Even VFR pilots who are
not in contact with ATC will be afforded greater protection from IFR aircraft and VFR aircraft that are receiving
traffic advisories. Nevertheless, pilots should never relax their visual scanning for other aircraft, and should
include the ADS−B In display (if equipped) in their normal traffic scan.
2. Air Traffic Control Radar Beacon System (ATCRBS) is similar to and compatible with military coded
radar beacon equipment. Civil Mode A is identical to military Mode 3.
3. Transponder and ADS-B operations on the ground. Civil and military aircraft should operate with
the transponder in the altitude reporting mode (consult the aircraft’s flight manual to determine the specific
transponder position to enable altitude reporting) and ADS−B Out transmissions enabled at all airports, any time
the aircraft is positioned on any portion of the airport movement area. This includes all defined taxiways and
runways. Pilots must pay particular attention to ATIS and airport diagram notations, General Notes (included
on airport charts), and comply with directions pertaining to transponder and ADS-B usage. Generally, these
directions are:
(a) Departures. Select the transponder mode which allows altitude reporting and enable ADS-B during
pushback or taxi-out from parking spot. Select TA or TA/RA (if equipped with TCAS) when taking the active
runway.
(b) Arrivals. If TCAS equipped, deselect TA or TA/RA upon leaving the active runway, but continue
transponder and ADS−B transmissions in the altitude reporting mode. Select STBY or OFF for transponder and
ADS−B upon arriving at the aircraft’s parking spot or gate.
4. Transponder and ADS-B Operations While Airborne.
(a) Unless otherwise requested by ATC, aircraft equipped with an ATC transponder maintained in
accordance with 14 CFR section 91.413 MUST operate with this equipment on the appropriate Mode 3/A code,
or other code as assigned by ATC, and with altitude reporting enabled whenever in controlled airspace. If
practicable, aircraft SHOULD operate with the transponder enabled in uncontrolled airspace.
(b) Aircraft equipped with ADS−B Out MUST operate with this equipment in the transmit mode at all
times, unless otherwise requested by ATC.
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5. Transponder and ADS−B Operation Under Visual Flight Rules (VFR).
(a) Unless otherwise instructed by an ATC facility, adjust transponder/ADS−B to reply on Mode 3/A
Code 1200 regardless of altitude.
(b) When required to operate their transponder/ADS−B, pilots must always operate that equipment with
altitude reporting enabled unless otherwise instructed by ATC or unless the installed equipment has not been
tested and calibrated as required by 14 CFR section 91.217. If deactivation is required, turn off altitude reporting.
(c) When participating in a VFR standard formation flight that is not receiving ATC services, only the
lead aircraft should operate its transponder and ADS −B Out and squawk code 1203. Once established in
formation, all other aircraft should squawk standby and disable ADS−B transmissions.
NOTE−
1. If the formation flight is receiving ATC services, pilots can expect ATC to direct all non−lead aircraft to STOP Squawk,
and should not do so until instructed.
2. Firefighting aircraft not in contact with ATC may squawk 1255 in lieu of 1200 while en route to, from, or within the
designated firefighting area(s).
3. VFR aircraft flying authorized SAR missions for the USAF or USCG may be advised to squawk 1277 in lieu of 1200 while
en route to, from, or within the designated search area.
4. VFR gliders should squawk 1202 in lieu of 1200.
REFERENCE−
F AA Order JO 7110.66, National Beacon Code Allocation Plan (NBCAP).
6. A pilot on an IFR flight who elects to cancel the IFR flight plan prior to reaching their destination, should
adjust the transponder/ADS−B according to VFR operations.
7. If entering a U.S. OFFSHORE AIRSPACE AREA from outside the U.S., the pilot should advise on first
radio contact with a U.S. radar ATC facility that such equipment is available by adding “transponder” or
“ADS−B” (if equipped) to the aircraft identification.
8. It should be noted by all users of ATC transponders and ADS −B Out systems that the surveillance
coverage they can expect is limited to “line of sight” with ground radar and ADS−B radio sites. Low altitude or
aircraft antenna shielding by the aircraft itself may result in reduced range or loss of aircraft contact. Though
ADS−B often provides superior reception at low altitudes, poor coverage from any surveillance system can be
improved by climbing to a higher altitude.
NOTE−
Pilots should refer to AIM, paragraph 4 −5−7, Automatic Dependent Surveillance − Broadcast (ADS−B) Services, for a
complete description of operating limitations and procedures.
b. Transponder/ADS−B Code Designation
1. For A TC to utilize one of the 4096 discrete codes, a four−digit code designation will be used; for example,
code 2102 will be expressed as “TWO ONE ZERO TWO.”
NOTE−
Circumstances may occasionally require ATC to assign a non−discrete code; i.e., a code ending in “00.”
REFERENCE−
F AA Order JO 7110.66, National Beacon Code Allocation Plan (NBCAP).
c. Automatic Altitude Reporting
1. Most transponders (Modes C and S) and all ADS−B Out systems are capable of automatic altitude
reporting. This system converts aircraft altitude in 100 −foot increments to coded digital information that is
transmitted to the appropriate surveillance facility as well as to ADS−B In and TCAS systems.
2. Adjust the transponder/ADS−B to reply on the Mode 3/A code specified by ATC and with altitude
reporting enabled, unless otherwise directed by ATC or unless the altitude reporting equipment has not been
tested and calibrated as required by 14 CFR section 91.217. If deactivation is required by ATC, turn off the
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altitude reporting feature of your transponder/ADS−B. An instruction by ATC to “STOP ALTITUDE SQUAWK,
ALTITUDE DIFFERS BY (number of feet) FEET,” may be an indication that the transmitted altitude
information is incorrect, or that the aircraft’s altimeter setting is incorrect. While an incorrect altimeter setting
has no effect on the transmitted altitude information, it will cause the aircraft to fly at a true altitude different from
the assigned altitude. When a controller indicates that an altitude readout is invalid, the pilot should verify that
the aircraft altimeter is set correctly.
NOTE−
Altitude encoders are preset at standard atmospheric pressure. Local altimeter correction is applied by the surveillance
facility before the altitude information is presented to ATC.
3. Pilots should report exact altitude or flight level to the nearest hundred foot increment when establishing
initial contact with an ATC facility. Exact altitude or flight level reports on initial contact provide ATC with
information that is required prior to using automatically reported altitude information for separation purposes.
This will significantly reduce altitude verification requests.
d. IDENT Feature
Transponder/ADS−B Out equipment must be operated only as specified by ATC. Activate the “IDENT” feature
only when requested by ATC.
e. Code Changes
1. When making routine code changes, pilots should avoid inadvertent selection of Codes 7500, 7600 or
7700 thereby causing momentary false alarms at automated ground facilities. For example, when switching from
Code 2700 to Code 7200, switch first to 2200 then to 7200, NOT to 7700 and then 7200. This procedure applies
to nondiscrete Code 7500 and all discrete codes in the 7600 and 7700 series (i.e., 7600−7677, 7700−7777) which
will trigger special indicators in automated facilities. Only nondiscrete Code 7500 will be decoded as the hijack
code.
2. Under no circumstances should a pilot of a civil aircraft operate the transponder on Code 7777. This code
is reserved for military interceptor operations.
3. Military pilots operating VFR or IFR within restricted/warning areas should adjust their transponders to
Code 4000 unless another code has been assigned by ATC.
f. Mode C Transponder and ADS−B Out Requirements
1. Specific details concerning requirements to carry and operate Mode C transponders and ADS−B Out, as
well as exceptions and ATC authorized deviations from those requirements, are found in 14 CFR sections 91.215,
91.225, and 99.13.
2. In general, the CFRs require aircraft to be equipped with an operable Mode C transponder and ADS−B
Out when operating:
(a) In Class A, Class B, or Class C airspace areas;
(b) Above the ceiling and within the lateral boundaries of Class B or Class C airspace up to 10,000 feet
MSL;
(c) Class E airspace at and above 10,000 feet MSL within the 48 contiguous states and the District of
Columbia, excluding the airspace at and below 2,500 feet AGL;
(d) Within 30 miles of a Class B airspace primary airport, below 10,000 feet MSL (commonly referred
to as the “Mode C Veil”);
(e) For ADS−B Out: Class E airspace at and above 3,000 feet MSL over the Gulf of America from the
coastline of the United States out to 12 nautical miles.
NOTE−
The airspace described in (e) above is specified in 14 CFR § 91.225 for ADS−B Out requirements. However, 14 CFR § 91.215
does not include this airspace for ATC transponder requirements.
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(f) Transponder and ADS−B Out requirements do not apply to any aircraft that was not originally
certificated with an electrical system, or that has not subsequently been certified with such a system installed,
including balloons and gliders. These aircraft may conduct operations without a transponder or ADS −B Out
when operating:
(1) Outside any Class B or Class C airspace area; and
(2) Below the altitude of the ceiling of a Class B or Class C airspace area designated for an airport, or
10,000 feet MSL, whichever is lower.
3. 14 CFR section 99.13 requires all aircraft flying into, within, or across the contiguous U.S. ADIZ be
equipped with a Mode C or Mode S transponder. Balloons, gliders and aircraft not equipped with an
engine−driven electrical system are excepted from this requirement.
REFERENCE−
AIM, Chapter 5, Section 6, National Security and Interception Procedures.
4. Pilots must ensure that their aircraft transponder/ADS−B is operating on an appropriate ATC−assigned
VFR/IFR code with altitude reporting enabled when operating in such airspace. If in doubt about the operational
status of either feature of your transponder while airborne, contact the nearest ATC facility or FSS and they will
advise you what facility you should contact for determining the status of your equipment.
5. In−flight requests for “immediate” deviation from the transponder requirements may be approved by
controllers only for failed equipment, and only when the flight will continue IFR or when weather conditions
prevent VFR descent and continued VFR flight in airspace not affected by the CFRs. All other requests for
deviation should be made at least 1 hour before the proposed operation by contacting the nearest Flight Service
or Air Traffic facility in person or by telephone. The nearest ARTCC will normally be the controlling agency
and is responsible for coordinating requests involving deviations in other ARTCC areas.
6. In−flight requests for “immediate” deviation from the ADS−B Out requirements may be approved by
ATC only for failed equipment, and may be accommodated based on workload, alternate surveillance
availability, or other factors. All other requests for deviation must be made at least 1 hour before the proposed
operation, following the procedures contained in Advisory Circular (AC) 90− 114, Automatic Dependent
Surveillance−Broadcast Operations.
g. Cooperative Surveillance Phraseology. Air traffic controllers, both civil and military, will use the
following phraseology when referring to operation of cooperative ATC surveillance equipment. Except as noted,
the following ATC instructions do not apply to military transponders operating in other than Mode 3/A/C/S.
1. SQUAWK (number). Operate radar beacon transponder/ADS −B on designated code with altitude
reporting enabled.
2. IDENT. Engage the “IDENT” feature (military I/P) of the transponder/ADS−B.
3. SQUAWK (number) AND IDENT. Operate transponder/ADS−B on specified code with altitude
reporting enabled, and engage the “IDENT” (military I/P) feature.
4. SQUAWK STANDBY. Switch transponder/ADS−B to standby position.
5. SQUAWK NORMAL. Resume normal transponder/ADS−B operation on previously assigned code.
(Used after “SQUAWK STANDBY ,” or by military after specific transponder tests).
6. SQUAWK ALTITUDE. Activate Mode C with automatic altitude reporting.
7. STOP ALTITUDE SQUAWK. Turn off automatic altitude reporting.
8. STOP SQUAWK (Mode in use). Stop transponder and ADS−B Out transmissions, or switch off only
specified mode of the aircraft transponder (military).
9. SQUAWK MA YDAY. Operate transponder/ADS−B in the emergency position (Mode A Code 7700 for
civil transponder. Mode 3 Code 7700 and emergency feature for military transponder.)
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10. SQUAWK VFR. Operate radar beacon transponder/ADS−B on Code 1200 in the Mode A/3, or other
appropriate VFR code, with altitude reporting enabled.
4−1−21. Airport Reservation Operations and Special Traffic Management Programs
This section describes procedures for obtaining required airport reservations at airports designated by the FAA
and for airports operating under Special Traffic Management Programs.
a. Slot Controlled Airports.
1. The FAA may adopt rules to require advance reservations for unscheduled operations at certain airports.
In addition to the information in the rules adopted by the FAA, a listing of the airports and relevant information
will be maintained on the FAA website www.fly.faa.gov/ecvrs.
2. The FAA has established an Airport Reservation Office (ARO) to receive and process reservations for
unscheduled flights at the slot controlled airports. The ARO uses the Enhanced Computer V oice Reservation
System (e−CVRS) to allocate reservations. Reservations will be available beginning 72 hours in advance of the
operation at the slot controlled airport. Standby lists are not maintained. Flights with declared emergencies do
not require reservations. Refer to the website for the current listing of slot controlled airports, limitations, and
reservation procedures.
3. For more detailed information on operations and reservation procedures at a Slot Controlled Airport,
please see 14 CFR part 93, Subpart K – High Density Traffic Airports.
b. Special Traffic Management Programs (STMP).
1. Special programs may be established when a location requires special traffic handling to accommodate
above normal traffic demand (for example, NFL Super Bowl, EAA AirVenture Oshkosh, SUN ’n FUN
Aerospace Expo) or reduced airport capacity (for example, significant airport runway closures for airport
construction). The special programs may remain in effect until the problem has been resolved or until local traffic
management procedures can handle the volume and a need for special handling no longer exists.
2. If an STMP is used to accommodate a special event, a domestic notice will be issued relaying the website
address: www.fly.faa.gov/estmp. Domestic notice information includes: what airports are included in the STMP,
the dates and times reservations are required, the time limits for reservation requests, the point of contact for
reservations, and any other instructions.
c. Making Reservations. Detailed information and User Instruction Guides for using the Web reservation
systems are available on the websites for the slot controlled airports (e −CVRS), www.fly.faa.gov/ecvrs; and
STMPs (e−STMP), www.fly.faa.gov/estmp.
NOTE−
Users may contact the ARO at (540) 422−4246 if they have a problem with their reservation.
d. Prior Permission Required (PPR).
1. A PPR may be required at locations where air traffic demand does not require an STMP, but operations
may be impacted by on−airport activity or by a nearby event.
2. Events that may require a PPR include, but are not limited to:
(a) Construction on or near an active runway requiring time to remove personnel and equipment.
(b) Limited ramp space for parking aircraft.
(c) Snow removal at airports without an operating control tower.
(d) General aviation operations into military airports.
3. Pilots are responsible for coordinating operations related to the PPR. Controllers may be aware of the
PPR, but they do not enforce or otherwise oversee compliance. Operations contrary to a PPR could result in a
safety hazard to persons or property on the ground.
Services Available to Pilots 4−1−22
AIM2/20/251/22/26 AIM
4. PPRs are disseminated via NOTAM or published in the airport remarks section of the Chart Supplement
and typically includes a phone number or frequency to coordinate operations. An identification number may be
issued that is to be included in the Remarks section of the flight plan. Major airports with PPRs are listed on the
FAA’s National Airspace System Status website (https://nasstatus.faa.gov).
4−1−22. Requests for Waivers and Authorizations from Title 14, Code of Federal
Regulations (14 CFR)
a. Requests for a Certificate of Waiver or Authorization (FAA Form 7711−2), or requests for renewal of a
waiver or authorization, may be accepted by any FAA facility and will be forwarded, if necessary, to the
appropriate office having waiver authority.
b. The grant of a Certificate of Waiver or Authorization from 14 CFR constitutes relief from specific
regulations, to the degree and for the period of time specified in the certificate, and does not waive any state law
or local ordinance. Should the proposed operations conflict with any state law or local ordinance, or require
permission of local authorities or property owners, it is the applicant’s responsibility to resolve the matter. The
holder of a waiver is responsible for compliance with the terms of the waiver and its provisions.
c. A waiver may be canceled at any time by the Administrator, the person authorized to grant the waiver, or
the representative designated to monitor a specific operation. In such case either written notice of cancellation,
or written confirmation of a verbal cancellation will be provided to the holder.
4−1−23. Weather Systems Processor
The Weather Systems Processor (WSP) was developed for use in the National Airspace System to provide
weather processor enhancements to selected Airport Surveillance Radar (ASR)−9 facilities. The WSP provides
Air Traffic with warnings of hazardous wind shear and microbursts. The WSP also provides users with terminal
area 6−level weather, storm cell locations and movement, as well as the location and predicted future position
and intensity of wind shifts that may affect airport operations.
Services Available to Pilots 4−1−23
2/20/25 AIM
Section 2. Radio Communications Phraseology
and Techniques
4−2−1. General
a. Radio communications are a critical link in the ATC system. The link can be a strong bond between pilot
and controller or it can be broken with surprising speed and disastrous results. Discussion herein provides basic
procedures for new pilots and also highlights safe operating concepts for all pilots.
b. The single, most important thought in pilot-controller communications is understanding. It is essential,
therefore, that pilots acknowledge each radio communication with ATC by using the appropriate aircraft call
sign. Brevity is important, and contacts should be kept as brief as possible, but controllers must know what you
want to do before they can properly carry out their control duties. And you, the pilot, must know exactly what
the controller wants you to do. Since concise phraseology may not always be adequate, use whatever words are
necessary to get your message across. Pilots are to maintain vigilance in monitoring air traffic control radio
communications frequencies for potential traffic conflicts with their aircraft especially when operating on an
active runway and/or when conducting a final approach to landing.
c. All pilots will find the Pilot/Controller Glossary very helpful in learning what certain words or phrases
mean. Good phraseology enhances safety and is the mark of a professional pilot. Jargon, chatter, and “CB” slang
have no place in ATC communications. The Pilot/Controller Glossary is the same glossary used in FAA Order
JO 7110.65, Air Traffic Control. We recommend that it be studied and reviewed from time to time to sharpen
your communication skills.
4−2−2. Radio Technique
a. Listen before you transmit. Many times you can get the information you want through ATIS or by
monitoring the frequency. Except for a few situations where some frequency overlap occurs, if you hear someone
else talking, the keying of your transmitter will be futile and you will probably jam their receivers causing them
to repeat their call. If you have just changed frequencies, pause, listen, and make sure the frequency is clear.
b. Think before keying your transmitter. Know what you want to say and if it is lengthy; e.g., a flight plan
or IFR position report, jot it down.
c. The microphone should be very close to your lips and after pressing the mike button, a slight pause may
be necessary to be sure the first word is transmitted. Speak in a normal, conversational tone.
d. When you release the button, wait a few seconds before calling again. The controller or FSS specialist may
be jotting down your number, looking for your flight plan, transmitting on a different frequency, or selecting the
transmitter for your frequency.
e. Be alert to the sounds or the lack of sounds in your receiver. Check your volume, recheck your frequency,
and make sure that your microphone is not stuck in the transmit position. Frequency blockage can, and has,
occurred for extended periods of time due to unintentional transmitter operation. This type of interference is
commonly referred to as a “stuck mike,” and controllers may refer to it in this manner when attempting to assign
an alternate frequency. If the assigned frequency is completely blocked by this type of interference, use the
procedures described for en route IFR radio frequency outage to establish or reestablish communications with
ATC.
f. Be sure that you are within the performance range of your radio equipment and the ground station
equipment. Remote radio sites do not always transmit and receive on all of a facility’s available frequencies,
particularly with regard to VOR sites where you can hear but not reach a ground station’s receiver. Remember
that higher altitudes increase the range of VHF “line of sight” communications.
Radio Communications Phraseology 4−2−1
AIM 2/20/25
4−2−3. Contact Procedures
a. Initial Contact.
1. The terms initial contact or initial callup means the first radio call you make to a given facility or the first
call to a different controller or FSS specialist within a facility. Use the following format:
(a) Name of the facility being called;
(b) Your full aircraft identification as filed in the flight plan or as discussed in paragraph 4−2−4, Aircraft
Call Signs;
(c) When operating on an airport surface, state your position.
(d) The type of message to follow or your request if it is short; and
(e) The word “Over” if required.
EXAMPLE−
1. “New York Radio, Mooney Three One One Echo.”
2. “Columbia Ground, Cessna Three One Six Zero Foxtrot, south ramp, I−F−R Memphis.”
3. “Miami Center, Baron Five Six Three Hotel, request V−F−R traffic advisories.”
2. Many FSSs are equipped with Remote Communications Outlets (RCOs) and can transmit on the same
frequency at more than one location. The frequencies available at specific locations are indicated on charts above
FSS communications boxes. To enable the specialist to utilize the correct transmitter, advise the location and the
frequency on which you expect a reply.
EXAMPLE−
St. Louis FSS can transmit on frequency 122.3 at either Farmington, Missouri, or Decatur, Illinois, if you are in the vicinity
of Decatur, your callup should be “Saint Louis radio, Piper Six Niner Six Yankee, receiving Decatur One Two Two Point
Three.”
3. If radio reception is reasonably assured, inclusion of your request, your position or altitude, and the
phrase “(ATIS) Information Charlie received” in the initial contact helps decrease radio frequency congestion.
Use discretion; do not overload the controller with information unneeded or superfluous. If you do not get a
response from the ground station, recheck your radios or use another transmitter, but keep the next contact short.
EXAMPLE−
“Atlanta Center, Duke Four One Romeo, request V−F−R traffic advisories, Twenty Northwest Rome, seven thousand five
hundred, over.”
b. Initial Contact When Your Transmitting and Receiving Frequencies are Different.
1. If you are attempting to establish contact with a ground station and you are receiving on a different
frequency than that transmitted, indicate the VOR name or the frequency on which you expect a reply. Most FSSs
and control facilities can transmit on several VOR stations in the area. Use the appropriate FSS call sign as
indicated on charts.
EXAMPLE−
New York FSS transmits on the Kennedy, the Hampton, and the Calverton VORTACs. If you are in the Calverton area, your
callup should be “New York radio, Cessna Three One Six Zero Foxtrot, receiving Calverton V−O−R, over.”
2. If the chart indicates FSS frequencies above the VORTAC or in the FSS communications boxes, transmit
or receive on those frequencies nearest your location.
3. When unable to establish contact and you wish to call any ground station, use the phrase “ANY RADIO
(tower) (station), GIVE CESSNA THREE ONE SI X ZERO FOXTROT A CALL ON (frequency) OR
(V−O−R).” If an emergency exists or you need assistance, so state.
c. Subsequent Contacts and Responses to Callup from a Ground Facility.
Use the same format as used for the initial contact except you should state your message or request with the callup
in one transmission. The ground station name and the word “Over” may be omitted if the message requires an
4−2−2 Radio Communications Phraseology
2/20/25 AIM
obvious reply and there is no possibility for misunderstandings. You should acknowledge all callups or
clearances unless the controller or FSS specialist advises otherwise. There are some occasions when controllers
must issue time-critical instructions to other aircraft, and they may be in a position to observe your response,
either visually or on radar. If the situation demands your response, take appropriate action or immediately advise
the facility of any problem. Acknowledge with your aircraft identification, either at the beginning or at the end
of your transmission, and one of the words “Wilco,” “Roger,” “Affirmative,” “Negative,” or other appropriate
remarks; e.g., “PIPER TWO ONE FOUR LIMA, ROGER.” If you have been receiving services; e.g., VFR traffic
advisories and you are leaving the area or changing frequencies, advise the ATC facility and terminate contact.
d. Acknowledgement of Frequency Changes.
1. When advised by ATC to change frequencies, acknowledge the instruction. If you select the new
frequency without an acknowledgement, the controller’s workload is increased because there is no way of
knowing whether you received the instruction or have had radio communications failure.
2. At times, a controller/specialist may be working a sector with multiple frequency assignments. In order
to eliminate unnecessary verbiage and to free the controller/specialist for higher priority transmissions, the
controller/specialist may request the pilot “(Identification), change to my frequency 134.5.” This phrase should
alert the pilot that the controller/specialist is only changing frequencies, not controller/specialist, and that initial
callup phraseology may be abbreviated.
EXAMPLE−
“United Two Twenty−Two on one three four point five” or “one three four point five, United Two Twenty−Two.”
e. Compliance with Frequency Changes.
When instructed by ATC to change frequencies, select the new frequency as soon as possible unless instructed
to make the change at a specific time, fix, or altitude. A delay in making the change could result in an untimely
receipt of important information. If you are instructed to make the frequency change at a specific time, fix, or
altitude, monitor the frequency you are on until reaching the specified time, fix, or altitudes unless instructed
otherwise by ATC.
REFERENCE−
AIM, Para 5−3−1, ARTCC Communications.
4−2−4. Aircraft Call Signs
a. Precautions in the Use of Call Signs.
1. Improper use of call signs can result in pilots executing a clearance intended for another aircraft. Call
signs should never be abbreviated on an initial contact or at any time when other aircraft call signs have similar
numbers/sounds or identical letters/number; e.g., Cessna 6132F, Cessna 1622F, Baron 123F, Cherokee 7732F,
etc.
EXAMPLE−
Assume that a controller issues an approach clearance to an aircraft at the bottom of a holding stack and an aircraft with
a similar call sign (at the top of the stack) acknowledges the clearance with the last two or three numbers of the aircraft’ s
call sign. If the aircraft at the bottom of the stack did not hear the clearance and intervene, flight safety would be affected,
and there would be no reason for either the controller or pilot to suspect that anything is wrong. This kind of “human factors”
error can strike swiftly and is extremely difficult to rectify.
2. Pilots, therefore, must be certain that aircraft identification is complete and clearly identified before
taking action on an ATC clearance. ATC specialists will not abbreviate call signs of air carrier or other civil
aircraft having authorized call signs. ATC specialists may initiate abbreviated call signs of other aircraft by using
the prefix and the last three digits/letters of the aircraft identification after communications are established. The
pilot may use the abbreviated call sign in subseque nt contacts with the ATC specialist. When aware of
similar/identical call signs, ATC specialists will take action to minimize errors by emphasizing certain
numbers/letters, by repeating the entire call sign, by repeating the prefix, or by asking pilots to use a different
call sign temporarily. Pilots should use the phrase “VERIFY CLEARANCE FOR (your complete call sign)” if
doubt exists concerning proper identity.
Radio Communications Phraseology 4−2−3
AIM 2/20/25
3. Civil aircraft pilots should state the aircraft type, model or manufacturer’s name, followed by the
digits/letters of the registration number. When the aircraft manufacturer’s name or model is stated, the prefix “N”
is dropped; e.g., Aztec Two Four Six Four Alpha.
EXAMPLE−
1. Bonanza Six Five Five Golf.
2. Breezy Six One Three Romeo Experimental (omit “Experimental” after initial contact).
4. Air Taxi or other commercial operators not having FAA authorized call signs should prefix their normal
identification with the phonetic word “Tango.”
EXAMPLE−
Tango Aztec Two Four Six Four Alpha.
5. Air carriers and commuter air carriers having FAA authorized call signs should identify themselves by
stating the complete call sign (using group form for the numbers) and the word “super” or “heavy” if appropriate.
EXAMPLE−
1. United Twenty−Five Heavy.
2. Midwest Commuter Seven Eleven.
6. Military aircraft use a variety of systems including serial numbers, word call signs, and combinations of
letters/numbers. Examples include Army Copter 48931; Air Force 61782; REACH 31792; Pat 157; Air Evac
17652; Navy Golf Alfa Kilo 21; Marine 4 Charlie 36, etc.
b. Air Ambulance Flights.
Because of the priority afforded air ambulance flights in the ATC system, extreme discretion is necessary when
using the term “MEDEV AC.” It is only intended for those missions of an urgent medical nature and to be utilized
only for that portion of the flight requiring priority handling. It is important for ATC to be aware of a flight’s
MEDEV AC status, and it is the pilot’s responsibility to ensure that this information is provided to ATC. ....
1. To receive priority handling from ATC, the pilot must verbally identify the flight in radio transmissions
by stating “MEDEV AC” followed by the FAA authorized call sign (ICAO 3LD, US Special, or local) or the
aircraft civil “N” registration numbers/letters.
EXAMPLE−
If the aircraft identification of the flight indicates DAL51, the pilot states “MEDEVAC Delta Fifty One.”
If the aircraft identification of the flight indicates MDSTR1, the pilot states “MEDEVAC Medstar One.”
If the aircraft identification of the flight indicates N123G or LN123G, the pilot states “MEDEVAC One Two Three Golf”.
2. If requested by the pilot, ATC will provide additional assistance (e.g., landline notifications) to expedite
ground handling of patients, vital organs, or urgently needed medical materials. When possible make these
requests to ATC via methods other than through ATC radio frequencies.
3. MEDEV AC flights may include:
(a) Civilian air ambulance flights responding to medical emergencies (e.g., first call to an accident scene,
carrying patients, organ donors, organs, or other urgently needed lifesaving medical material).
(b) Air carrier and air taxi flights responding to medical emergencies. The nature of these medical
emergency flights usually concerns the transportation of urgently needed lifesaving medical materials or vital
organs, but can include inflight medical emergencies. It is imperative that the company/pilot determine, by the
nature/urgency of the specific medical cargo, if priority ATC assistance is required.
4. When filing a flight plan, pilots may include “L” for MEDEV AC with the aircraft registration
letters/digits and/or include “MEDEVAC” in Item 11 (Remarks) of the flight plan or Item 18 (Other Information)
of an international flight plan. However, ATC will only use these flight plan entries for informational purposes
or as a visual indicator. ATC will only provide prio rity handling when the pilot verbally identifies the
“MEDEV AC” status of the flight as described in subparagraph b1 above.
4−2−4 Radio Communications Phraseology
2/20/25 AIM
NOTE−
Civilian air ambulance aircraft operating VFR and without a filed flight plan are eligible for priority handling in accordance
with subparagraph b1 above.
5. ATC will also provide priority handling to HOSP and AIR EV AC flights when verbally requested. These
aircraft may file “HOSP” or “AIR EV AC” in either Item 11 (Remarks) of the flight plan or Item 18 of an
international flight plan. For aircraft identification in radio transmissions, civilian pilots will use normal call
signs when filing “HOSP” and military pilots will use the “EV AC” call sign.
c. Student Pilots Radio Identification.
1. The FAA desires to help student pilots in acquiring sufficient practical experience in the environment in
which they will be required to operate. To receive additional assistance while operating in areas of concentrated
air traffic, student pilots need only identify themselves as a student pilot during their initial call to an FAA radio
facility.
EXAMPLE−
Dayton tower, Fleetwing One Two Three Four, student pilot.
2. This special identification will alert FAA ATC personnel and enable them to provide student pilots with
such extra assistance and consideration as they may need. It is recommended that student pilots identify
themselves as such, on initial contact with each clearance delivery prior to taxiing, ground control, tower,
approach and departure control frequency, or FSS contact.
4−2−5. Description of Interchange or Leased Aircraft
a. Controllers issue traffic information based on familiarity with airline equipment and color/markings. When
an air carrier dispatches a flight using another company’s equipment and the pilot does not advise the terminal
ATC facility, the possible confusion in aircraft identification can compromise safety.
b. Pilots flying an “interchange” or “leased” aircraft not bearing the colors/markings of the company
operating the aircraft should inform the terminal ATC facility on first contact the name of the operating company
and trip number, followed by the company name as displayed on the aircraft, and aircraft type.
EXAMPLE−
Air Cal Three Eleven, United (interchange/lease), Boeing Seven Two Seven.
4−2−6. Ground Station Call Signs
Pilots, when calling a ground station, should begin with the name of the facility being called followed by the type
of the facility being called as indicated in TBL 4−2−1.
TBL 4−2−1
Calling a Ground Station
Facility Call Sign
Airport UNICOM “Shannon UNICOM”
FAA Flight Service Station “Chicago Radio”
Airport Traffic Control Tower “Augusta Tower”
Clearance Delivery Position (IFR) “Dallas Clearance Delivery”
Ground Control Position in Tower “Miami Ground”
Radar or Nonradar Approach
Control Position
“Oklahoma City Approach”
Radar Departure Control Position “St. Louis Departure”
FAA Air Route Traffic Control
Center
“Washington Center”
Radio Communications Phraseology 4−2−5
AIM 2/20/25
4−2−7. Phonetic Alphabet
The International Civil Aviation Organization (ICAO) phonetic alphabet is used by FAA personnel when
communications conditions are such that the information cannot be readily received without their use. ATC
facilities may also request pilots to use phonetic letter equivalents when aircraft with similar sounding
identifications are receiving communications on the same frequency. Pilots should use the phonetic alphabet
when identifying their aircraft during initial contact with air traffic control facilities. Additionally, use the
phonetic equivalents for single letters and to spell out groups of letters or difficult words during adverse
communications conditions. (See TBL 4−2−2.)
TBL 4−2−2
Phonetic Alphabet/Morse Code
Character Morse Code Telephony Phonic
(Pronunciation)
A ● — Alfa (AL−FAH)
B — ● ● ● Bravo (BRAH−VOH)
C — ● — ● Charlie (CHAR−LEE) or
(SHAR−LEE)
D — ● ● Delta (DELL−TAH)
E ● Echo (ECK−OH)
F ● ● — ● Foxtrot (FOKS−TROT)
G — — ● Golf (GOLF)
H ● ● ● ● Hotel (HOH−TEL)
I ● ● India (IN−DEE−AH)
J ● — — — Juliett (JEW−LEE−ETT)
K — ● — Kilo (KEY−LOH)
L ● — ● ● Lima (LEE−MAH)
M — — Mike (MIKE)
N — ● November (NO−VEM−BER)
O — — — Oscar (OSS−CAH)
P ● — — ● Papa (PAH−PAH)
Q — — ● — Quebec (KEH−BECK)
R ● — ● Romeo (ROW−ME−OH)
S ● ● ● Sierra (SEE−AIR−RAH)
T — Tango (TANG−GO)
● ● — Uniform (YOU−NEE−FORM)
or
(OO−NEE−FORM)
V ● ● ● — Victor (VIK−TAH)
W ● — — Whiskey (WISS−KEY)
X — ● ● — Xray (ECKS−RAY)
Y — ● — — Yankee (YANG−KEY)
Z — — ● ● Zulu (ZOO−LOO)
1 ● — — — — One (WUN)
2 ● ● — — — Two (TOO)
3 ● ● ● — — Three (TREE)
4 ● ● ● ● — Four (FOW−ER)
5 ● ● ● ● ● Five (FIFE)
6 — ● ● ● ● Six (SIX)
4−2−6 Radio Communications Phraseology
2/20/25 AIM
7 — — ● ● ● Seven (SEV−EN)
8 — — — ● ● Eight (AIT)
9 — — — — ● Nine (NIN−ER)
0 — — — — — Zero (ZEE−RO)
4−2−8. Figures
a. Figures indicating hundreds and thousands in round number, as for ceiling heights, and upper wind levels
up to 9,900 must be spoken in accordance with the following.
EXAMPLE−
1. 500 ........ five hundred
2. 4,500 ...... four thousand five hundred
b. Numbers above 9,900 must be spoken by separating the digits preceding the word “thousand.”
EXAMPLE−
1. 10,000 ..... one zero thousand
2. 13,500 ..... one three thousand five hundred
c. Transmit airway or jet route numbers as follows.
EXAMPLE−
1. V12 ....... Victor Twelve
2. J533 ....... J Five Thirty−Three
d. All other numbers must be transmitted by pronouncing each digit.
EXAMPLE−
10 ........... one zero
e. When a radio frequency contains a decimal point, the decimal point is spoken as “POINT.”
EXAMPLE−
122.1 ......... one two two point one
NOTE−
ICAO procedures require the decimal point be spoken as “DECIMAL.” The F AA will honor such usage by military aircraft
and all other aircraft required to use ICAO procedures.
4−2−9. Altitudes and Flight Levels
a. Up to but not including 18,000 feet MSL, state the separate digits of the thousands plus the hundreds if
appropriate.
EXAMPLE−
1. 12,000 ..... one two thousand
2. 12,500 ..... one two thousand five hundred
b. At and above 18,000 feet MSL (FL 180), state the words “flight level” followed by the separate digits of
the flight level.
EXAMPLE−
1. 190 ........ Flight Level One Niner Zero
2. 275 ........ Flight Level Two Seven Five
4−2−10. Directions
The three digits of bearing, course, heading, or wind direction should always be magnetic. The word “true” must
be added when it applies.
Radio Communications Phraseology 4−2−7
AIM 2/20/25
EXAMPLE−
1. (Magnetic course) 005 ...... zero zero five
2. (True course) 050 .......... zero five zero true
3. (Magnetic bearing) 360 ..... three six zero
4. (Magnetic heading) 100 ..... heading one zero zero
5. (Wind direction) 220 ........ wind two two zero
4−2−11. Speeds
The separate digits of the speed followed by the word “KNOTS.” Except, controllers may omit the word
“KNOTS” when using speed adjustment procedures; e.g., “REDUCE/INCREASE SPEED TO TWO FIVE
ZERO.”
EXAMPLE−
(Speed) 250 ................. two five zero knots
(Speed) 190 ................. one niner zero knots
The separate digits of the Mach Number preceded by “Mach.”
EXAMPLE−
(Mach number) 1.5 ............ Mach one point five
(Mach number) 0.64 ........... Mach point six four
(Mach number) 0.7 ............ Mach point seven
4−2−12. Time
a. FAA uses Coordinated Universal Time (UTC) for all operations. The word “local” or the time zone
equivalent must be used to denote local when local time is given during radio and telephone communications.
The term “Zulu” may be used to denote UTC.
EXAMPLE−
0920 UTC ..... zero niner two zero,
zero one two zero pacific or local,
or one twenty AM
b. To convert from Standard Time to Coordinated Universal Time:
TBL 4−2−3
Standard Time to Coordinated Universal Time
Eastern Standard Time ......... Add 5 hours
Central Standard Time ......... Add 6 hours
Mountain Standard Time ....... Add 7 hours
Pacific Standard Time ......... Add 8 hours
Alaska Standard Time ......... Add 9 hours
Hawaii Standard Time ......... Add 10 hours
NOTE−
For daylight time, subtract 1 hour.
c. A reference may be made to local daylight or standard time utilizing the 24−hour clock system. The hour
is indicated by the first two figures and the minutes by the last two figures.
EXAMPLE−
0000 ....................... zero zero zero zero
0920 ....................... zero niner two zero
d. Time may be stated in minutes only (two figures) in radiotelephone communications when no
misunderstanding is likely to occur.
Radio Communications Phraseology 4−2−8
2/20/25 AIM
e. Current time in use at a station is stated in the nearest quarter minute in order that pilots may use this
information for time checks. Fractions of a quarter minute less than 8 seconds are stated as the preceding quarter
minute; fractions of a quarter minute of 8 seconds or more are stated as the succeeding quarter minute.
EXAMPLE−
0929:05 ...... time, zero niner two niner
0929:10 ...... time, zero niner two niner and one−quarter
4−2−13. Communications with Tower when Aircraft Transmitter or Receiver or Both are
Inoperative
a. Arriving Aircraft.
1. Receiver inoperative.
(a) If you have reason to believe your receiver is inoperative, remain outside or above the Class D surface
area until the direction and flow of traffic has been determined; then, advise the tower of your type aircraft,
position, altitude, intention to land, and request that you be controlled with light signals.
REFERENCE−
AIM, Para 4−3−13, Traffic Control Light Signals.
(b) When you are approximately 3 to 5 miles from the airport, advise the tower of your position and join
the airport traffic pattern. From this point on, watch the tower for light signals. Thereafter, if a complete pattern
is made, transmit your position downwind and/or turning base leg.
2. Transmitter inoperative. Remain outside or above the Class D surface area until the direction and flow
of traffic has been determined; then, join the airport traffic pattern. Monitor the primary local control frequency
as depicted on Sectional Charts for landing or traffic information, and look for a light signal which may be
addressed to your aircraft. During hours of daylight, acknowledge tower transmissions or light signals by rocking
your wings. At night, acknowledge by blinking the landing or navigation lights. To acknowledge tower
transmissions during daylight hours, hovering helicopters will turn in the direction of the controlling facility and
flash the landing light. While in flight, helicopters should show their acknowledgement of receiving a
transmission by making shallow banks in opposite directions. At night, helicopters will acknowledge receipt of
transmissions by flashing either the landing or the search light.
3. Transmitter and receiver inoperative. Remain outside or above the Class D surface area until the
direction and flow of traffic has been determined; then, join the airport traffic pattern and maintain visual contact
with the tower to receive light signals. Acknowledge light signals as noted above.
b. Departing Aircraft. If you experience radio failure prior to leaving the parking area, make every effort
to have the equipment repaired. If you are unable to have the malfunction repaired, call the tower by telephone
and request authorization to depart without two-way radio communications. If tower authorization is granted,
you will be given departure information and requested to monitor the tower frequency or watch for light signals
as appropriate. During daylight hours, acknowledge tower transmissions or light signals by moving the ailerons
or rudder. At night, acknowledge by blinking the landing or navigation lights. If radio malfunction occurs after
departing the parking area, watch the tower for light signals or monitor tower frequency.
REFERENCE−
14 CFR Section 91.125 and 14 CFR Section 91.129.
4−2−14. Communications for VFR Flights
a. FSSs and Supplemental Weather Service Locations (SWSL) are allocated frequencies for different
functions; for example, in Alaska, certain FSSs provide Local Airport Advisory on 123.6 MHz or other
frequencies which can be found in the Chart Supplement. If you are in doubt as to what frequency to use,
122.2 MHz is assigned to the majority of FSSs as a common en route simplex frequency.
NOTE−
In order to expedite communications, state the frequency being used and the aircraft location during initial callup.
Radio Communications Phraseology 4−2−9
AIM 2/20/25
EXAMPLE−
Dayton radio, November One Two Three Four Five on one two two point two, over Springfield V−O−R, over.
b. Certain VOR voice channels are being utilized for recorded broadcasts; for example, ATIS. These services
and appropriate frequencies are listed in the Chart Supplement. On VFR flights, pilots are urged to monitor these
frequencies. When in contact with a control facility, notify the controller if you plan to leave the frequency to
monitor these broadcasts.
4−2−10 Radio Communications Phraseology
AIM2/20/257/9/26 AIM
Section 3. Airport Operations
4−3−1. General
Increased traffic congestion, aircraft in climb and descent attitudes, and pilot preoccupation with cockpit duties
are some factors that increase the hazardous accident potential near the airport. The situation is further
compounded when the weather is marginal, that is, just meeting VFR requirements. Pilots must be particularly
alert when operating in the vicinity of an airport. This section defines some rules, practices, and procedures that
pilots should be familiar with and adhere to for safe airport operations.
4−3−2. Airports with an Operating Control Tower
a. When operating at an airport where traffic control is being exercised by a control tower, pilots are required
to maintain two−way radio contact with the tower while operating within the Class B, Class C, and Class D
surface area unless the tower authorizes otherwise. Initial callup should be made about 15 miles from the airport.
Unless there is a good reason to leave the tower frequency before exiting the Class B, Class C, and Class D
surface areas, it is a good operating practice to remain on the tower frequency for the purpose of receiving traffic
information. In the interest of reducing tower frequency congestion, pilots are reminded that it is not necessary
to request permission to leave the tower frequency once outside of Class B, Class C, and Class D surface areas.
Not all airports with an operating control tower will have Class D airspace. These airports do not have weather
reporting which is a requirement for surface based controlled airspace, previously known as a control zone. The
controlled airspace over these airports will normally begin at 700 feet or 1,200 feet above ground level and can
be determined from the visual aeronautical charts. Pilots are expected to use good operating practices and
communicate with the control tower as described in this section.
b. When necessary, the tower controller will issue clearances or other information for aircraft to generally
follow the desired flight path (traffic patterns) when flying in Class B, Class C, and Class D surface areas and
the proper taxi routes when operating on the ground. If not otherwise authorized or directed by the tower, pilots
of fixed−wing aircraft approaching to land must circle the airport to the left. Pilots approaching to land in a
helicopter must avoid the flow of fixed−wing traffic. However, in all instances, an appropriate clearance must
be received from the tower before landing.
Airport Operations 4−3−1
AIM 2/20/253/15/077110.65R CHG 2AIM 7/9/26
FIG 4−3−1
Components of a Traffic Pattern
NOTE−
This diagram is intended only to illustrate terminology used in identifying various components of a traffic pattern. It should
not be used as a reference or guide on how to enter a traffic pattern.
c. The following terminology for the various components of a traffic pattern has been adopted as standard for
use by control towers and pilots (See FIG 4−3−1):
1. Departure. The flight path that begins after takeoff and continues straight ahead along the extended
runway centerline. The departure climb continues until reaching a point at least 1/2 mile beyond the departure
end of the runway and within 300 feet of the traffic pattern altitude.
2. Upwind leg. A flight path that begins after departure and continues straight ahead along the extended
runway centerline. Upwind leg is an extension of departure and is used when issuing control instructions for
separation, spacing, or sequencing.
3. Crosswind leg. A flight path at right angles to the landing runway off its takeoff end.
4. Downwind leg. A flight path parallel to the landing runway in the opposite direction of landing.
5. Base leg. A flight path at right angles to the landing runway off its approach end and extending from
the downwind leg to the intersection of the extended runway centerline.
6. Final approach. A flight path in the direction of landing along the extended runway centerline from the
base leg to the runway.
d. Many towers are equipped with a tower radar displa y. The radar uses are intended to enhance the
effectiveness and efficiency of the local control, or tower, position. They are not intended to provide radar
services or benefits to pilots except as they may accrue through a more efficient tower operation. The four basic
uses are:
1. To determine an aircraft’s exact location. This is accomplished by radar identifying the VFR aircraft
through any of the techniques available to a radar position, such as having the aircraft squawk ident. Once
identified, the aircraft’s position and spatial relationship to other aircraft can be quickly determined, and standard
instructions regarding VFR operation in Class B, Class C, and Class D surface areas will be issued. Once initial
4−3−2 Airport Operations
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radar identification of a VFR aircraft has been established and the appropriate instructions have been issued,
radar monitoring may be discontinued; the reason being that the local controller’s primary means of surveillance
in VFR conditions is visually scanning the airport and local area.
2. To provide radar traffic advisories. Radar traffic advisories may be provided to the extent that the
local controller is able to monitor the radar display. Local control has primary control responsibilities to the
aircraft operating on the runways, which will normally supersede radar monitoring duties.
3. To provide a direction or suggested heading. The local controller may provide pilots flying VFR with
generalized instructions which will facilitate operations; e.g., “PROCEED SOUTHWESTBOUND, ENTER A
RIGHT DOWNWIND RUNWAY THREE ZERO,” or provide a suggested heading to establish radar
identification or as an advisory aid to navigation; e.g., “SUGGESTED HEADING TWO TWO ZERO, FOR
RADAR IDENTIFICATION.” In both cases, the instructions are advisory aids to the pilot flying VFR and are
not radar vectors.
NOTE−
Pilots have complete discretion regarding acceptance of the suggested headings or directions and have sole responsibility
for seeing and avoiding other aircraft.
4. To provide information and instructions to aircraft operating within Class B, Class C, and Class D
surface areas. In an example of this situation, the local controller would use the radar to advise a pilot on an
extended downwind when to turn base leg.
NOTE−
The above tower radar applications are intended to augment the standard functions of the local control position. There is
no controller requirement to maintain constant radar identification. In fact, such a requirement could compromise the local
controller’ s ability to visually scan the airport and local area to meet F AA responsibilities to the aircraft operating on the
runways and within the Class B, Class C, and Class D surface areas. Normally, pilots will not be advised of being in radar
contact since that continued status cannot be guaranteed and since the purpose of the radar identification is not to establish
a link for the provision of radar services.
e. A few of the radar equipped towers are authorized to use the radar to ensure separation between aircraft in
specific situations, while still others may function as limited radar approach controls. The various radar uses are
strictly a function of FAA operational need. The facilities may be indistinguishable to pilots since they are all
referred to as tower and no publication lists the degree of radar use. Therefore, when in communication with a
tower controller who may have radar available, do not assume that constant radar monitoring and complete ATC
radar services are being provided.
4−3−3. Traffic Patterns
a. It is recommended that aircraft enter the airport traffic pattern at one of the following altitudes listed below.
These altitudes should be maintained unless another traffic pattern altitude is published in the Chart Supplement
or unless otherwise required by the applicable distance from cloud criteria (14 CFR section 91.155). (See
FIG 4−3−2 and FIG 4−3−3):
1. Propeller−driven aircraft enter the traffic pattern at 1,000 feet above ground level (AGL).
2. Large and turbine−powered aircraft enter the traffic pattern at an altitude of not less than 1,500 feet AGL
or 500 feet above the established pattern altitude.
3. Helicopters operating in the traffic pattern may fly a pattern similar to the fixed−wing aircraft pattern,
but at a lower altitude (500 AGL) and closer to the runway. This pattern may be on the opposite side of the runway
from fixed−wing traffic when airspeed requires or for practice power−off landings (autorotation) and if local
policy permits. Landings not to the runway must avoid the flow of fixed wing traffic.
b. A pilot may vary the size of the traffic pattern depending on the aircraft’s performance characteristics. Pilots
of en route aircraft should be constantly alert for aircraft in traffic patterns and avoid these areas whenever
possible.
Airport Operations 4−3−3
AIM 2/20/25
c. Unless otherwise indicated, all turns in the traffic pattern must be made to the left, except for helicopters,
as applicable.
d. On Sectional, Aeronautical, and VFR Terminal Ar ea Charts, right traffic patterns are indicated at
public−use and joint−use airports with the abbreviation “RP” (for Right Pattern), followed by the appropriate
runway number(s) at the bottom of the airport data block.
EXAMPLE−
RP 9, 18, 22R
NOTE−
1. Pilots are encouraged to use the standard traffic pattern. However, those pilots who choose to execute a straight −in
approach, maneuvering for and execution of the approach should not disrupt the flow of arriving and departing traffic.
Likewise, pilots operating in the traffic pattern should be alert at all times for aircraft executing straight−in approaches.
REFERENCE−
AC 90−66, Non−Towered Airport Flight Operations.
2. *RP indicates special conditions exist and refers pilots to the Chart Supplement.
3. Right traffic patterns are not shown at airports with full−time control towers.
e. Wind conditions affect all airplanes in varying degrees. Figure 4-3-4 is an example of a chart used to
determine the headwind, crosswind, and tailwind components based on wind direction and velocity relative to
the runway. Pilots should refer to similar information provided by the aircraft manufacturer when determining
these wind components.
4−3−4 Airport Operations
AIM2/20/257/9/26 AIM
FIG 4−3−2
Traffic Pattern Operations
Single Runway
EXAMPLE−
Key to traffic pattern operations
1. Enter pattern in level flight, abeam the midpoint of the runway, at pattern altitude.
2. Maintain pattern altitude until abeam approach end of the landing runway on downwind leg.
3. Complete turn to final at least 1/4 mile from the runway.
4. Continue straight ahead until beyond departure end of runway.
5. If remaining in the traffic pattern, commence turn to crosswind leg beyond the departure end of the runway within 300
feet of pattern altitude.
6. If departing the traffic pattern, continue straight out, or exit with a 45 degree turn (to the left when in a left−hand traffic
pattern; to the right when in a right−hand traffic pattern) beyond the departure end of the runway, after reaching pattern
altitude.
Airport Operations 4−3−5
AIM 2/20/253/15/077110.65R CHG 2AIM 7/9/26
FIG 4−3−3
Traffic Pattern Operations
Parallel Runways
EXAMPLE−
Key to traffic pattern operations
1. Enter pattern in level flight, abeam the midpoint of the runway, at pattern altitude.
2. Maintain pattern altitude until abeam approach end of the landing runway on downwind leg.
3. Complete turn to final at least 1/4 mile from the runway.
4. Continue straight ahead until beyond departure end of runway.
5. If remaining in the traffic pattern, commence turn to crosswind leg beyond the departure end of the runway within 300
feet of pattern altitude.
6. If departing the traffic pattern, continue straight out, or exit with a 45 degree turn (to the left when in a left−hand traffic
pattern; to the right when in a right−hand traffic pattern) beyond the departure end of the runway, after reaching pattern
altitude.
4−3−6 Airport Operations
AIM2/20/257/9/26 AIM
7. Do not overshoot final or continue on a track which will penetrate the final approach of the parallel runway.
8. Do not continue on a track which will penetrate the departure path of the parallel runway.
FIG 4−3−4
Headwind/Tailwind/Crosswind Component Calculator
4−3−4. Visual Indicators at Airports Without an Operating Control Tower
a. At those airports without an operating control tower, a segmented circle visual indicator system, if installed,
is designed to provide traffic pattern information.
REFERENCE−
AIM, Para 4−1−9, Traffic Advisory Practices at Airports Without Operating Control Towers.
b. The segmented circle system consists of the following components:
Airport Operations 4−3−7
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1. The segmented circle. Located in a position affording maximum visibility to pilots in the air and on the
ground and providing a centralized location for other elements of the system.
2. The wind direction indicator. A wind cone, wind sock, or wind tee installed near the operational
runway to indicate wind direction. The large end of the wind cone/wind sock points into the wind as does the
large end (cross bar) of the wind tee. In lieu of a tetrahedron and where a wind sock or wind cone is collocated
with a wind tee, the wind tee may be manually aligned with the runway in use to indicate landing direction. These
signaling devices may be located in the center of the segmented circle and may be lighted for night use. Pilots
are cautioned against using a tetrahedron to indicate wind direction.
3. The landing direction indicator. A tetrahedron is installed when conditions at the airport warrant its
use. It may be used to indicate the direction of landings and takeoffs. A tetrahedron may be located at the center
of a segmented circle and may be lighted for night operations. The small end of the tetrahedron points in the
direction of landing. Pilots are cautioned against using a tetrahedron for any purpose other than as an indicator
of landing direction. Further, pilots should use extreme caution when making runway selection by use of a
tetrahedron in very light or calm wind conditions as the tetrahedron may not be aligned with the designated
calm−wind runway. At airports with control towers, the tetrahedron should only be referenced when the control
tower is not in operation. Tower instructions supersede tetrahedron indications.
4. Landing strip indicators. Installed in pairs as shown in the segmented circle diagram and used to show
the alignment of landing strips.
5. Traffic pattern indicators. Arranged in pairs in conjunction with landing strip indicators and used to
indicate the direction of turns when there is a variation from the normal left traffic pattern. (If there is no
segmented circle installed at the airport, traffic pattern indicators may be installed on or near the end of the
runway.)
c. Preparatory to landing at an airport without a control tower, or when the control tower is not in operation,
pilots should concern themselves with the indicator for the approach end of the runway to be used. When
approaching for landing, all turns must be made to the left unless a traffic pattern indicator indicates that turns
should be made to the right. If the pilot will mentally enlarge the indicator for the runway to be used, the base
and final approach legs of the traffic pattern to be flown immediately become apparent. Similar treatment of the
indicator at the departure end of the runway will clearly indicate the direction of turn after takeoff.
d. When two or more aircraft are approaching an airport for the purpose of landing, the pilot of the aircraft
at the lower altitude has the right−of−way over the pilot of the aircraft at the higher altitude. However, the pilot
operating at the lower altitude should not take advantage of another aircraft, which is on final approach to land,
by cutting in front of, or overtaking that aircraft.
4−3−5. Unexpected Maneuvers in the Airport Traffic Pattern
There have been several incidents in the vicinity of controlled airports that were caused primarily by aircraft
executing unexpected maneuvers. ATC service is based upon observed or known traffic and airport conditions.
Controllers establish the sequence of arriving and departing aircraft by requiring them to adjust flight as
necessary to achieve proper spacing. These adjustments can only be based on observed traffic, accurate pilot
reports, and anticipated aircraft maneuvers. Pilots are expected to cooperate so as to preclude disrupting traffic
flows or creating conflicting patterns. The pilot−in−command of an aircraft is directly responsible for and is the
final authority as to the operation of the aircraft. On occasion it may be necessary for pilots to maneuver their
aircraft to maintain spacing with the traffic they have been sequenced to follow. The controller can anticipate
minor maneuvering such as shallow “S” turns. The controller cannot, however, anticipate a major maneuver such
as a 360 degree turn. If a pilot makes a 360 degree turn after obtaining a landing sequence, the result is usually
a gap in the landing interval and, more importantly, it causes a chain reaction which may result in a conflict with
following traffic and an interruption of the sequence established by the tower or approach controller. Should a
pilot decide to make maneuvering turns to maintain spacing behind a preceding aircraft, the pilot should always
advise the controller if at all possible. Except when requested by the controller or in emergency situations, a 360
4−3−8 Airport Operations
AIM2/20/257/9/26 AIM
degree turn should never be executed in the traffic pattern or when receiving radar service without first advising
the controller.
4−3−6. Use of Runways/Declared Distances
a. Runways are identified by numbers that indicate the nearest 10 −degree increment of the azimuth of the
runway centerline. For example, where the magnetic azimuth is 183 degrees, the runway designation would be
18; for a magnetic azimuth of 87 degrees, the runway designation would be 9. For a magnetic azimuth ending
in the number 5, such as 185, the runway designation could be either 18 or 19. Wind direction issued by the tower
is also magnetic and wind velocity is in knots.
NOTE−
1. At airports with multiple parallel r unways whose magnetic azimuths are iden tical, each runway number will be
supplemented by a letter and shown from left to right when viewed from the direction of approach.
2. When multiple parallel runways at the same airport are separated by a large distance, such as by a central terminal or
several terminals, the runways may be designated as non−parallel runways to avoid pilot confusion.
REFERENCE−
AC 150/5340−1, Standards for Airport Markings, Para 2.3.5, Characteristics.
b. Airport proprietors are responsible for taking the lead in local aviation noise control. Accordingly, they may
propose specific noise abatement plans to the FAA. If approved, these plans are applied in the form of Formal
or Informal Runway Use Programs for noise abatement purposes.
REFERENCE−
Pilot/Controller Glossary Term− Runway Use Program.
1. ATC will assign the runway/s most nearly aligned with the wind when 5 knots or more, or the “calm wind”
runway when less than 5 knots unless:
(a) Use of another runway is operationally advantageous, or
(b) A Runway Use Program is in effect.
NOTE−
Tailwind and crosswind considerations take precedence o ver delay/capacity considerations, and noise abatement
operations/procedures.
REFERENCE−
F AA Order JO 7110.65, Para 3−5−1, Selection.
c. If a pilot prefers to use a runway different from that specified, the pilot is expected to advise ATC. ATC may
honor such requests as soon as is operationally practicable. ATC will advise pilots when the requested runway
is noise sensitive. When use of a runway other than the one assigned is requested, pilot cooperation is encouraged
to preclude disruption of traffic flows or the creation of conflicting patterns.
REFERENCE−
F AA Order JO 7110.65, Para 3−5−1, Selection.
d. Declared Distances.
1. Declared distances for a runway represent the maximum distances available and suitable for meeting
takeoff and landing distance performance requirements. These distances are determined in accordance with FAA
runway design standards by adding to the physical length of paved runway any clearway or stopway and
subtracting from that sum any lengths necessary to obtain the standard runway safety areas, runway object free
areas, or runway protection zones. As a result of these additions and subtractions, the declared distances for a
runway may be more or less than the physical length of the runway as depicted on aeronautical charts and related
publications, or available in electronic navigation databases provided by either the U.S. Government or
commercial companies.
2. All 14 CFR part 139 airports report declared distances for each runway. Other airports may also report
declared distances for a runway if necessary to meet runway design standards or to indicate the presence of a
clearway or stopway. Where reported, declared distances for each runway end are published in the Chart
Airport Operations 4−3−9
AIM 2/20/253/15/077110.65R CHG 2AIM 7/9/26
Supplement. For runways without published declared distances, the declared distances may be assumed to be
equal to the physical length of the runway unless there is a displaced landing threshold, in which case the Landing
Distance Available (LDA) is shortened by the amount of the threshold displacement.
NOTE−
A symbol
is shown on U.S. Government charts to indicate that runway declared distance information is available (See
appropriate Chart Supplement, Chart Supplement Alaska or Pacific).
(a) The FAA uses the following definitions for runway declared distances (See FIG 4−3−5):
REFERENCE−
Pilot/Controller Glossary Terms: “Accelerate−Stop Distance Available,” “Landing Distance Available,” “Takeoff Distance Available,” “Takeoff Run
Available,” ” Stopway,” and “Clearway.”
(1) Takeoff Run Available (TORA) – The runway length declared available and suitable for the ground
run of an airplane taking off.
The TORA is typically the physical length of the runway, but it may be shorter than the runway length if necessary
to satisfy runway design standards. For example, the TORA may be shorter than the runway length if a portion
of the runway must be used to satisfy runway protection zone requirements.
(2) Takeoff Distance Available (TODA) – The takeoff run available plus the length of any remaining
runway or clearway beyond the far end of the takeoff run available.
The TODA is the distance declared available for satisfying takeoff distance requirements for airplanes where the
certification and operating rules and available performance data allow for the consideration of a clearway in
takeoff performance computations.
NOTE−
The length of any available clearway will be included in the TODA published in the entry for that runway end within the
Chart Supplement.
(3) Accelerate−Stop Distance Available (ASDA) – The runway plus stopway length declared available
and suitable for the acceleration and deceleration of an airplane aborting a takeoff.
The ASDA may be longer than the physical length of the runway when a stopway has been designated available
by the airport operator, or it may be shorter than the physical length of the runway if necessary to use a portion
of the runway to satisfy runway design standards; for example, where the airport operator uses a portion of the
runway to achieve the runway safety area requirement. ASDA is the distance used to satisfy the airplane
accelerate−stop distance performance requirements where the certification and operating rules require
accelerate−stop distance computations.
NOTE−
The length of any available stopway will be included in the ASDA published in the entry for that runway end within the Chart
Supplement.
(4) Landing Distance Available (LDA) − The runway length declared available and suitable for a
landing airplane.
The LDA may be less than the physical length of the runway or the length of the runway remaining beyond a
displaced threshold if necessary to satisfy runway design standards;for example, where the airport operator uses
a portion of the runway to achieve the runway safety area requirement.
Although some runway elements (such as stopway length and clearway length) may be available information,
pilots must use the declared distances determined by the airport operator and not attempt to independently
calculate declared distances by adding those elements to the reported physical length of the runway.
(b) The airplane operating rules and/or the airplane operating limitations establish minimum distance
requirements for takeoff and landing and are based on performance data supplied in the Airplane Flight Manual
or Pilot’s Operating Handbook. The minimum distances required for takeoff and landing obtained either in
planning prior to takeoff or in performance assessments conducted at the time of landing must fall within the
applicable declared distances before the pilot can accept that runway for takeoff or landing.
4−3−10 Airport Operations
AIM2/20/257/9/26 AIM
(c) Runway design standards may impose restrictions on the amount of runway available for use in
takeoff and landing that are not apparent from the reported physical length of the runway or from runway
markings and lighting. The runway elements of Runway Safety Area (RSA), Runway Object Free Area (ROFA),
and Runway Protection Zone (RPZ) may reduce a runway’s declared distances to less than the physical length
of the runway at geographically constrained airports (See FIG 4−3−6). When considering the amount of runway
available for use in takeoff or landing performance calculations, the declared distances published for a runway
must always be used in lieu of the runway’s physical length.
REFERENCE−
AC 150/5300−13, Airport Design.
(d) While some runway elements associated with declared distances may be identifiable through runway
markings or lighting (for example, a displaced threshold or a stopway), the individual declared distance limits
are not marked or otherwise identified on the runway. An aircraft is not prohibited from operating beyond a
declared distance limit during the takeoff, landing, or taxi operation provided the runway surface is appropriately
marked as usable runway (See FIG 4−3−6). The following examples clarify the intent of this paragraph.
REFERENCE−
AIM, Para 2−3−3, Runway Markings.
AC 150/5340−1, Standards for Airport Markings.
EXAMPLE−
1. The declared LDA for runway 9 must be used when showing compliance with the landing distance requirements of the
applicable airplane operating rules and/or airplane operating limitations or when making a before landing performance
assessment. The LDA is less than the physical runway length, not only because of the displaced threshold, but also because
of the subtractions necessary to meet the RSA beyond the far end of the runway. However, during the actual landing
operation, it is permissible for the airplane to roll beyond the unmarked end of the LDA.
2. The declared ASDA for runway 9 must be used when showing compliance with the accelerate−stop distance requirements
of the applicable airplane operating rules and/or airplane operating limitations. The ASDA is less than the physical length
of the runway due to subtractions necessary to achieve the full RSA requirement. However, in the event of an aborted takeoff,
it is permissible for the airplane to roll beyond the unmarked end of the ASDA as it is brought to a full−stop on the remaining
usable runway.
Airport Operations 4−3−11
AIM 2/20/253/15/077110.65R CHG 2AIM 7/9/26
FIG 4−3−5
Declared Distances with Full−Standard Runway Safety Areas, Runway Object Free Areas, and Runway
Protection Zones
4−3−12 Airport Operations
AIM2/20/257/9/26 AIM
FIG 4−3−6
Effects of a Geographical Constraint on a Runway’s Declared Distances
NOTE−
A runway’ s RSA begins a set distance prior to the threshold and will extend a set distance beyond the end of the runway
depending on the runway’ s design criteria. If these required lengths cannot be achieved, the ASDA and/or LDA will be
reduced as necessary to obtain the required lengths to the extent practicable.
4−3−7. Low Level Wind Shear/Microburst Detection Systems
Low Level Wind Shear Alert System (LLWAS), Terminal Doppler Weather Radar (TDWR), Weather Systems
Processor (WSP), and Integrated Terminal Weather System (ITWS) display information on hazardous wind
shear and microburst activity in the vicinity of an airport to air traffic controllers who relay this information to
pilots.
a. LLWAS provides wind shear alert and gust front information but does not provide microburst alerts. The
LLWAS is designed to detect low level wind shear conditions around the periphery of an airport. It does not detect
wind shear beyond that limitation. Controllers will provide this information to pilots by giving the pilot the
airport wind followed by the boundary wind.
Airport Operations 4−3−13
AIM 2/20/253/15/077110.65R CHG 2AIM 7/9/26
EXAMPLE−
Wind shear alert, airport wind 230 at 8, south boundary wind 170 at 20.
b. LLWAS “network expansion,” (LLWAS NE) and LLWAS Relocation/Sustainment (LLWAS −RS) are
systems integrated with TDWR. These systems provide the capability of detecting microburst alerts and wind
shear alerts. Controllers will issue the appropriate wind shear alerts or microburst alerts. In some of these systems
controllers also have the ability to issue wind information oriented to the threshold or departure end of the
runway.
EXAMPLE−
Runway 17 arrival microburst alert, 40 knot loss 3 mile final.
REFERENCE−
AIM, Para 7−1−24, Microbursts.
c. More advanced systems are in the field or being developed such as ITWS. ITWS provides alerts for
microbursts, wind shear, and significant thunderstorm activity. ITWS displays wind information oriented to the
threshold or departure end of the runway.
d. The WSP provides weather processor enhancements to selected Airport Surveillance Radar (ASR) −9
facilities. The WSP provides Air Traffic with detection and alerting of hazardous weather such as wind shear,
microbursts, and significant thunderstorm activity. The WSP displays terminal area 6 level weather, storm cell
locations and movement, as well as the location and predicted future position and intensity of wind shifts that
may affect airport operations. Controllers will receive and issue alerts based on Areas Noted for Attention
(ARENA). An ARENA extends on the runway center line from a 3 mile final to the runway to a 2 mile departure.
e. An airport equipped with the LLWAS, ITWS, or WSP is so indicated in the Chart Supplement under
Weather Data Sources for that particular airport.
4−3−8. Braking Action Reports and Advisories
a. When available, ATC furnishes pilots the quality of braking action received from pilots. The quality of
braking action is described by the terms “good,” “good to medium,” “medium,” “medium to poor,” “poor,” and
“nil.” When pilots report the quality of braking action by using the terms noted above, they should use descriptive
terms that are easily understood, such as, “braking action poor the first/last half of the runway,” together with
the particular type of aircraft.
b. FICON NOTAMs will provide contaminant measurements for paved runways; however, a FICON
NOTAM for braking action will only be used for non−paved runway surfaces, taxiways, and aprons. These
NOTAMs are classified according to the most critical term (“good to medium,” “medium,” “medium to poor,”
and “poor”).
1. FICON NOTAM reporting of a braking condition for paved runway surfaces is not permissible by
Federally Obligated Airports or those airports certificated under 14 CFR part 139.
2. A “NIL” braking condition at these airports must be mitigated by closure of the affected surface. Do not
include the type of vehicle in the FICON NOTAM.
c. When tower controllers receive runway braking action reports which include the terms medium, poor, or
nil, or whenever weather conditions are conducive to deteriorating or rapidly changing runway braking
conditions, the tower will include on the A TIS broadcast the statement, “BRAKING ACTION ADVISORIES ARE
IN EFFECT.”
d. During the time that braking action advisories are in effect, ATC will issue the most recent braking action
report for the runway in use to each arriving and departing aircraft. Pilots should be prepared for deteriorating
braking conditions and should request current runway condition information if not issued by controllers. Pilots
should also be prepared to provide a descriptive runway condition report to controllers after landing.
4−3−9. Runway Condition Reports
a. Aircraft braking coefficient is dependent upon the surface friction between the tires on the aircraft wheels
and the pavement surface. Less friction means less aircraft braking coefficient and less aircraft braking response.
4−3−14 Airport Operations
AIM2/20/257/9/26 AIM
b. Runway condition code (RwyCC) values range from 1 (poor) to 6 (dry). For frozen contaminants on
runway surfaces, a runway condition code reading of 4 indicates the level when braking deceleration or
directional control is between good and medium.
NOTE−
A RwyCC of “0” is used to delineate a braking action report of NIL and is prohibited from being reported in a FICON
NOTAM.
c. Airport management should conduct runway condition assessments on wet runways or runways covered
with compacted snow and/or ice.
1. Numerical readings may be obtained by using the Runway Condition Assessment Matrix (RCAM). The
RCAM provides the airport operator with data to complete the report that includes the following:
(a) Runway(s) in use
(b) Time of the assessment
(c) Runway condition codes for each zone (touchdown, mid−point, roll−out)
(d) Pilot−reported braking action report (if available)
(e) The contaminant (for example, wet snow, dry snow, slush, ice, etc.)
2. Assessments for each zone (see 4−3−9c1(c)) will be issued in the direction of takeoff and landing on the
runway, ranging from “1” to “6” to describe contaminated surfaces.
NOTE−
A RwyCC of “0” is used to delineate a braking action report of NIL and is prohibited from being reported in a FICON
NOTAM.
3. When any 1 or more runway condition codes are reported as less than 6, airport management must notify
ATC for dissemination to pilots.
4. Controllers will not issue runway condition codes when all 3 segments of a runway are reporting values
of 6.
d. When runway condition code reports are provided by airport management, the ATC facility providing
approach control or local airport advisory must provide the report to all pilots.
e. Pilots should use runway condition code information with other knowledge including aircraft performance
characteristics, type, and weight, previous experience, wind conditions, and aircraft tire type (such as bias ply
vs. radial constructed) to determine runway suitability.
f. The Runway Condition Assessment Matrix identifies the descriptive terms “good,” “good to medium,”
“medium,” “medium to poor,” “poor,” and “nil” used in braking action reports.
REFERENCE−
Advisory Circular AC 91−79, Mitigating the Risks of a Runway Overrun Upon Landing, Appendix 1.
Airport Operations 4−3−15
AIM 2/20/253/15/077110.65R CHG 2AIM 7/9/26
FIG 4−3−7
Runway Condition Assessment Matrix (RCAM)
4−3−10. Intersection Takeoffs
a. In order to enhance airport capacities, reduce taxiing distances, minimize departure delays, and provide for
more efficient movement of air traffic, controllers may initiate intersection takeoffs as well as approve them when
the pilot requests. If for ANY reason a pilot prefers to use a different intersection or the full length of the runway
or desires to obtain the distance between the intersection and the runway end, THE PILOT IS EXPECTED TO
INFORM ATC ACCORDINGLY .
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AIM2/20/257/9/26 AIM
b. Pilots are expected to assess the suitability of an intersection for use at takeoff during their preflight
planning. They must consider the resultant length reduction to the published runway length and to the published
declared distances from the intersection intended to be used for takeoff. The minimum runway required for
takeoff must fall within the reduced runway length and the reduced declared distances before the intersection
can be accepted for takeoff.
REFERENCE−
AIM, Para 4−3−6, Use of Runways/Declared Distances.
c. Controllers will issue the measured distance from the intersection to the runway end rounded “down” to
the nearest 50 feet to any pilot who requests and to all military aircraft, unless use of the intersection is covered
in appropriate directives. Controllers, however, will not be able to inform pilots of the distance from the
intersection to the end of any of the published declared distances.
REFERENCE−
F AA Order JO 7110.65, Para 3−7−1, Ground Traffic Movement.
d. An aircraft is expected to taxi to (but not onto) the end of the assigned runway unless prior approval for
an intersection departure is received from ground control.
e. Pilots should state their position on the airport when calling the tower for takeoff from a runway
intersection.
EXAMPLE−
Cleveland T ower , Apache Three Seven Two Two Papa, at the intersection of taxiway Oscar and runway two three right, ready
for departure.
f. Controllers are required to separate small aircraft that are departing from an intersection on the same runway
(same or opposite direction) behind a large nonheavy aircraft (except B757), by ensuring that at least a 3−minute
interval exists between the time the preceding large aircraft has taken off and the succeeding small aircraft begins
takeoff roll. The 3 −minute separation requirement will also be applied to small aircraft with a maximum
certificated takeoff weight of 12,500 pounds or less departing behind a small aircraft with a maximum
certificated takeoff weight of more than 12,500 pounds. To inform the pilot of the required 3−minute hold, the
controller will state, “Hold for wake turbulence.” If after considering wake turbulence hazards, the pilot feels
that a lesser time interval is appropriate, the pilot may request a waiver to the 3−minute interval. To initiate such
a request, simply say “Request waiver to 3−minute interval” or a similar statement. Controllers may then issue
a takeoff clearance if other traffic permits, since the pilot has accepted the responsibility for wake turbulence
separation.
g. The 3−minute interval is not required when the intersection is 500 feet or less from the departure point of
the preceding aircraft and both aircraft are taking off in the same direction. Controllers may permit the small
aircraft to alter course after takeoff to avoid the flight path of the preceding departure.
h. A 4−minute interval is mandatory for small, large, and heavy aircraft behind a super aircraft. The 3−minute
interval is mandatory behind a heavy aircraft in all cases, and for small aircraft behind a B757.
4−3−11. Pilot Responsibilities When Conducting Land and Hold Short Operations (LAHSO)
a. LAHSO is an acronym for “Land and Hold Short Operations.” These operations include landing and
holding short of an intersecting runway, an intersecting taxiway, or some other designated point on a runway
other than an intersecting runway or taxiway. (See FIG 4−3−8, FIG 4−3−9, FIG 4−3−10.)
b. Pilot Responsibilities and Basic Procedures.
1. LAHSO is an air traffic control procedure that requires pilot participation to balance the needs for
increased airport capacity and system efficiency, consistent with safety. This procedure can be done safely
provided pilots and controllers are knowledgeable and understand their responsibilities. The following
paragraphs outline specific pilot/operator responsibilities when conducting LAHSO.
2. At controlled airports, air traffic may clear a pilot to land and hold short. Pilots may accept such a
clearance provided that the pilot−in−command determines that the aircraft can safely land and stop within the
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Available Landing Distance (ALD). ALD data are published in the Chart Supplement and in the U.S. Terminal
Procedures Publications. Controllers will also provide ALD data upon request. Student pilots or pilots not
familiar with LAHSO should not participate in the program.
3. The pilot−in−command has the final authority to accept or decline any land and hold short clearance. The
safety and operation of the aircraft remain the responsibility of the pilot. Pilots are expected to decline a LAHSO
clearance if they determine it will compromise safety.
4. To conduct LAHSO, pilots should become familiar with all available information concerning LAHSO
at their destination airport. Pilots should have, readily available, the published ALD and runway slope
information for all LAHSO runway combinations at each airport of intended landing. Additionally, knowledge
about landing performance data permits the pilot to readily determine that the ALD for the assigned runway is
sufficient for safe LAHSO. As part of a pilot’s preflight planning process, pilots should determine if their
destination airport has LAHSO. If so, their preflight planning process should include an assessment of which
LAHSO combinations would work for them given their aircraft’s required landing distance. Good pilot decision
making is knowing in advance whether one can accept a LAHSO clearance if offered.
FIG 4−3−8
Land and Hold Short of an Intersecting Runway
EXAMPLE−
FIG 4−3−10 − holding short at a designated point may be required to avoid conflicts with the runway safety area/flight path
of a nearby runway.
NOTE−
Each figure shows the approximate location of LAHSO markings, signage, and in−pavement lighting when installed.
REFERENCE−
AIM, Chapter 2, Aeronautical Lighting and Other Airport Visual Aids.
4−3−18 Airport Operations
AIM2/20/257/9/26 AIM
FIG 4−3−9
Land and Hold Short of an Intersecting Taxiway
FIG 4−3−10
Land and Hold Short of a Designated Point on a Runway Other Than an Intersecting Runway or Taxiway
5. If, for any reason, such as difficulty in discerning the location of a LAHSO intersection, wind conditions,
aircraft condition, etc., the pilot elects to request to land on the full length of the runway, to land on another
runway, or to decline LAHSO, a pilot is expected to promptly inform air traffic, ideally even before the clearance
is issued. A LAHSO clearance, once accepted, must be adhered to, just as any other ATC clearance, unless an
amended clearance is obtained or an emergency occurs. A LAHSO clearance does not preclude a rejected
landing.
6. A pilot who accepts a LAHSO clearance should land and exit the runway at the first convenient taxiway
(unless directed otherwise) before reaching the hold short point. Otherwise, the pilot must stop and hold at the
hold short point. If a rejected landing becomes necessary after accepting a LAHSO clearance, the pilot should
maintain safe separation from other aircraft or vehicles, and should promptly notify the controller.
7. Controllers need a full read back of all LAHSO clearances. Pilots should read back their LAHSO
clearance and include the words, “HOLD SHORT OF (RUNWAY/TAXIWAY/OR POINT)” in their
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acknowledgment of all LAHSO clearances. In order to reduce frequency congestion, pilots are encouraged to
read back the LAHSO clearance without prompting. Don’t make the controller have to ask for a read back!
c. LAHSO Situational Awareness
1. Situational awareness is vital to the success of LAHSO. Situational awareness starts with having current
airport information in the cockpit, readily accessible to the pilot. (An airport diagram assists pilots in identifying
their location on the airport, thus reducing requests for “progressive taxi instructions” from controllers.)
2. Situational awareness includes effective pilot−controller radio communication. ATC expects pilots to
specifically acknowledge and read back all LAHSO clearances as follows:
EXAMPLE−
ATC: “(Aircraft ID) cleared to land runway six right, hold short of taxiway bravo for crossing traffic (type aircraft).”
Aircraft: “(Aircraft ID), wilco, cleared to land runway six right to hold short of taxiway bravo.”
ATC: “(Aircraft ID) cross runway six right at taxiway bravo, landing aircraft will hold short.”
Aircraft: “(Aircraft ID), wilco, cross runway six right at bravo, landing traffic (type aircraft) to hold.”
3. For those airplanes flown with two crewmembers, effective intra−cockpit communication between
cockpit crewmembers is also critical. There have been several instances where the pilot working the radios
accepted a LAHSO clearance but then simply forgot to tell the pilot flying the aircraft.
4. Situational awareness also includes a thorough understanding of the airport markings, signage, and
lighting associated with LAHSO. These visual aids consist of a three−part system of yellow hold−short markings,
red and white signage and, in certain cases, in −pavement lighting. Visual aids assist the pilot in determining
where to hold short. FIG 4− 3−8, FIG 4−3−9, FIG 4−3−10 depict how these markings, signage, and lighting
combinations will appear once installed. Pilots are cautioned that not all airports conducting LAHSO have
installed any or all of the above markings, signage, or lighting.
5. Pilots should only receive a LAHSO clearance when there is a minimum ceiling of 1,000 feet and 3
statute miles visibility. The intent of having “basic” VFR weather conditions is to allow pilots to maintain visual
contact with other aircraft and ground vehicle operations. Pilots should consider the effects of prevailing inflight
visibility (such as landing into the sun) and how it may affect overall situational awareness. Additionally, surface
vehicles and aircraft being taxied by maintenance personnel may also be participating in LAHSO, especially in
those operations that involve crossing an active runway.
4−3−12. Low Approach
a. A low approach (sometimes referred to as a low pass) is the go−around maneuver following an approach.
Instead of landing or making a touch−and−go, a pilot may wish to go around (low approach) in order to expedite
a particular operation (a series of practice instrument approaches is an example of such an operation). Unless
otherwise authorized by ATC, the low approach should be made straight ahead, with no turns or climb made until
the pilot has made a thorough visual check for other aircraft in the area.
b. When operating within a Class B, Class C, and Class D surface area, a pilot intending to make a low
approach should contact the tower for approval. This request should be made prior to starting the final approach.
c. When operating to an airport, not within a Class B, Class C, and Class D surface area, a pilot intending to
make a low approach should, prior to leaving the final approach fix inbound (nonprecision approach) or the outer
marker or fix used in lieu of the outer marker inbound (precision approach), so advise the FSS, UNICOM, or
make a broadcast as appropriate.
REFERENCE−
AIM, Para 4−1−9, Traffic Advisory Practices at Airports Without Operating Control Towers.
4−3−13. Traffic Control Light Signals
a. The following procedures are used by ATCTs in the control of aircraft, ground vehicles, equipment, and
personnel not equipped with radio. These same procedures will be used to control aircraft, ground vehicles,
4−3−20 Airport Operations
AIM2/20/257/9/26 AIM
equipment, and personnel equipped with radio if radio contact cannot be established. ATC personnel use a
directive traffic control signal which emits an intense narrow light beam of a selected color (either red, white,
or green) when controlling traffic by light signals.
b. Although the traffic signal light offers the advantage that some control may be exercised over nonradio
equipped aircraft, pilots should be cognizant of the disadvantages which are:
1. Pilots may not be looking at the control tower at the time a signal is directed toward their aircraft.
2. The directions transmitted by a light signal are very limited since only approval or disapproval of a pilot’s
anticipated actions may be transmitted. No supplement or explanatory information may be transmitted except
by the use of the “General Warning Signal” which advises the pilot to be on the alert.
c. Between sunset and sunrise, a pilot wishing to attract the attention of the control tower should turn on a
landing light and taxi the aircraft into a position, clear of the active runway, so that light is visible to the tower.
The landing light should remain on until appropriate signals are received from the tower.
d. Airport Traffic Control Tower Light Gun Signals. (See TBL 4−3−1.)
e. During daylight hours, acknowledge tower transmissions or light signals by moving the ailerons or rudder.
At night, acknowledge by blinking the landing or navigation lights. If radio malfunction occurs after departing
the parking area, watch the tower for light signals or monitor tower frequency.
TBL 4−3−1
Airport Traffic Control Tower Light Gun Signals
Meaning
Color and Type of Signal Movement of Vehicles,
Equipment and Personnel Aircraft on the Ground Aircraft in Flight
Steady green Cleared to cross, proceed or go Cleared for takeoff Cleared to land
Flashing green Not applicable Cleared for taxi Return for landing (to be
followed by steady green at the
proper time)
Steady red STOP STOP Give way to other aircraft and
continue circling
Flashing red Clear the taxiway/runway Taxi clear of the runway in use Airport unsafe, do not land
Flashing white Return to starting point on airport Return to starting point on airport Not applicable
Alternating red and green Exercise extreme caution Exercise extreme caution Exercise extreme caution
4−3−14. Communications
a. Pilots of departing aircraft should communicate with the control tower on the appropriate ground
control/clearance delivery frequency prior to starting engines to receive engine start time, taxi and/or clearance
information. Unless otherwise advised by the tower, remain on that frequency during taxiing and runup, then
change to local control frequency when ready to request takeoff clearance.
NOTE−
Pilots are encouraged to monitor the local tower frequency as soon as practical consistent with other ATC requirements.
REFERENCE−
AIM, Para 4−1−13, Automatic Terminal Information Service (ATIS).
b. The tower controller will consider that pilots of turbine−powered aircraft are ready for takeoff when they
reach the runway or warm−up block unless advised otherwise.
c. The majority of ground control frequencies are in the 121.6 −121.9 MHz bandwidth. Ground control
frequencies are provided to eliminate frequency congestion on the tower (local control) frequency and are limited
to communications between the tower and aircraft on the ground and between the tower and utility vehicles on
the airport, provide a clear VHF channel for arriving and departing aircraft. They are used for issuance of taxi
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information, clearances, and other necessary contacts between the tower and aircraft or other vehicles operated
on the airport. A pilot who has just landed should not change from the tower frequency to the ground control
frequency until directed to do so by the controller. Normally, only one ground control frequency is assigned at
an airport; however, at locations where the amount of traffic so warrants, a second ground control frequency
and/or another frequency designated as a clearance delivery frequency, may be assigned.
d. A controller may omit the ground or local control frequency if the controller believes the pilot knows which
frequency is in use. If the ground control frequency is in the 121 MHz bandwidth the controller may omit the
numbers preceding the decimal point; e.g., 121.7, “CONTACT GROUND POINT SEVEN.” However, if any
doubt exists as to what frequency is in use, the pilot should promptly request the controller to provide that
information.
e. Controllers will normally avoid issuing a radio frequency change to helicopters, known to be
single−piloted, which are hovering, air taxiing, or flying near the ground. At times, it may be necessary for pilots
to alert A TC regarding single pilot operations to minimize delay of essential ATC communications. Whenever
possible, A TC instructions will be relayed through the frequency being monitored until a frequency change can
be accomplished. You must promptly advise ATC if you are unable to comply with a frequency change. Also,
you should advise ATC if you must land to accomplish the frequency change unless it is clear the landing will
have no impact on other air traffic; e.g., on a taxiway or in a helicopter operating area.
4−3−15. Gate Holding Due to Departure Delays
a. Pilots should contact ground control or clearance delivery prior to starting engines as gate hold procedures
will be in effect whenever departure delays exceed or are anticipated to exceed 15 minutes. The sequence for
departure will be maintained in accordance with initial call up unless modified by flow control restrictions. Pilots
should monitor the ground control or clearance delivery frequency for engine startup advisories or new proposed
start time if the delay changes.
b. The tower controller will consider that pilots of turbine−powered aircraft are ready for takeoff when they
reach the runway or warm−up block unless advised otherwise.
4−3−16. VFR Flights in Terminal Areas
Use reasonable restraint in exercising the prerogative of VFR flight, especially in terminal areas. The weather
minimums and distances from clouds are minimums. Giving yourself a greater margin in specific instances is
just good judgment.
a. Approach Area. Conducting a VFR operation in a Class B, Class C, Class D, and Class E surface area
when the official visibility is 3 or 4 miles is not prohibited, but good judgment would dictate that you keep out
of the approach area.
b. Reduced Visibility. It has always been recognized that precipitation reduces forward visibility.
Consequently, although again it may be perfectly legal to cancel your IFR flight plan at any time you can proceed
VFR, it is good practice, when precipitation is occurring, to continue IFR operation into a terminal area until you
are reasonably close to your destination.
c. Simulated Instrument Flights. In conducting simulated instrument flights, be sure that the weather is
good enough to compensate for the restricted visibility of the safety pilot and your greater concentration on your
flight instruments. Give yourself a little greater margin when your flight plan lies in or near a busy airway or close
to an airport.
4−3−17. VFR Helicopter Operations at Controlled Airports
a. General.
1. The following ATC procedures and phraseologies recognize the unique capabilities of helicopters and
were developed to improve service to all users. Helicopter design characteristics and user needs often require
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AIM2/20/257/9/26 AIM
operations from movement areas and nonmovement areas within the airport boundary. In order for ATC to
properly apply these procedures, it is essential that pilots familiarize themselves with the local operations and
make it known to controllers when additional instructions are necessary.
2. Insofar as possible, helicopter operations will be instructed to avoid the flow of fixed−wing aircraft to
minimize overall delays; however, there will be ma ny situations where faster/larger helicopters may be
integrated with fixed−wing aircraft for the benefit of all concerned. Examples would include IFR flights,
avoidance of noise sensitive areas, or use of runways/taxiways to minimize the hazardous effects of rotor
downwash in congested areas.
3. Because helicopter pilots are intimately familiar with the effects of rotor downwash, they are best
qualified to determine if a given operation can be conducted safely. Accordingly, the pilot has the final authority
with respect to the specific airspeed/altitude combinations. ATC clearances are in no way intended to place the
helicopter in a hazardous position. It is expected that pilots will advise ATC if a specific clearance will cause
undue hazards to persons or property.
b. Controllers normally limit ATC ground service and instruction to movement areas; therefore, operations
from nonmovement areas are conducted at pilot discretion and should be based on local policies, procedures, or
letters of agreement. In order to maximize the flexibility of helicopter operations, it is necessary to rely heavily
on sound pilot judgment. For example, hazards such as debris, obstructions, vehicles, or personnel must be
recognized by the pilot, and action should be taken as necessary to avoid such hazards. Taxi, hover taxi, and air
taxi operations are considered to be ground movements. Helicopters conducting such operations are expected
to adhere to the same conditions, requirements, and practices as apply to other ground taxiing and ATC
procedures in the AIM.
1. The phraseology taxi is used when it is intended or expected that the helicopter will taxi on the airport
surface, either via taxiways or other prescribed routes. Taxi is used primarily for helicopters equipped with
wheels or in response to a pilot request. Preference should be given to this procedure whenever it is necessary
to minimize effects of rotor downwash.
2. Pilots may request a hover taxi when slow forward movement is desired or when it may be appropriate
to move very short distances. Pilots should avoid this procedure if rotor downwash is likely to cause damage to
parked aircraft or if blowing dust/snow could obscure visibility. If it is necessary to operate above 25 feet AGL
when hover taxiing, the pilot should initiate a request to ATC.
3. Air taxi is the preferred method for helicopter ground movements on airports provided ground operations
and conditions permit. Unless otherwise requested or instructed, pilots are expected to remain below 100 feet
AGL. However, if a higher than normal airspeed or altitude is desired, the request should be made prior to lift−off.
The pilot is solely responsible for selecting a safe airspeed for the altitude/operation being conducted. Use of air
taxi enables the pilot to proceed at an optimum airspeed/altitude, minimize downwash effect, conserve fuel, and
expedite movement from one point to another. Helicopters should avoid overflight of other aircraft, vehicles, and
personnel during air−taxi operations. Caution must be exercised concerning active runways and pilots must be
certain that air taxi instructions are understood. Special precautions may be necessary at unfamiliar airports or
airports with multiple/intersecting active runways. The taxi procedures given in paragraph 4 −3−18, Taxiing,
paragraph 4−3−19, Taxi During Low Visibility, and paragraph 4−3−21, Exiting the Runway After Landing, also
apply.
REFERENCE−
Pilot/Controller Glossary Term− T axi.
Pilot/Controller Glossary Term− Hover Taxi.
Pilot/Controller Glossary Term− Air Taxi.
c. Takeoff and Landing Procedures.
1. Helicopter operations may be conducted from a runway, taxiway, portion of a landing strip, or any clear
area which could be used as a landing site such as the scene of an accident, a construction site, or the roof of a
building. The terms used to describe designated areas from which helicopters operate are: movement area,
landing/takeoff area, apron/ramp, heliport and helipad (See Pilot/Controller Glossary). These areas may be
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improved or unimproved and may be separate from or located on an airport/heliport. ATC will issue takeoff
clearances from movement areas other than active runways, or in diverse directions from active runways, with
additional instructions as necessary. Whenever possible, takeoff clearance will be issued in lieu of extended
hover/air taxi operations. Phraseology will be “CLEARED FOR TAKEOFF FROM (taxiway, helipad, runway
number, etc.), MAKE RIGHT/ LEFT TURN FOR (direction, heading, NA VAID radial) DEPARTURE/DEPAR-
TURE ROUTE (number, name, etc.).” Unless requested by the pilot, downwind takeoffs will not be issued if
the tailwind exceeds 5 knots.
2. Pilots should be alert to wind information as well as to wind indications in the vicinity of the helicopter.
ATC should be advised of the intended method of departing. A pilot request to takeoff in a given direction
indicates that the pilot is willing to accept the wind condition and controllers will honor the request if traffic
permits. Departure points could be a significant distance from the control tower and it may be difficult or
impossible for the controller to determine the helicopter’s relative position to the wind.
3. If takeoff is requested from nonmovement areas, an area not authorized for helicopter use, an area not
visible from the tower, an unlighted area at night, or an area off the airport, the phraseology “DEPARTURE
FROM (requested location) WILL BE AT YOUR OWN RISK (additional instructions, as necessary). USE
CAUTION (if applicable).” The pilot is responsible for operating in a safe manner and should exercise due
caution.
4. Similar phraseology is used for helicopter landing operations. Every effort will be made to permit
helicopters to proceed direct and land as near as possible to their final destination on the airport. Traffic density,
the need for detailed taxiing instructions, frequency congestion, or other factors may affect the extent to which
service can be expedited. As with ground movement operations, a high degree of pilot/controller cooperation
and communication is necessary to achieve safe and efficient operations.
4−3−18. Taxiing
a. General. Approval must be obtained prior to moving an aircraft or vehicle onto the movement area during
the hours an Airport Traffic Control Tower is in operation.
1. Always state your position on the airport when calling the tower for taxi instructions.
2. The movement area is normally described in local bulletins issued by the airport manager or control
tower. These bulletins may be found in FSSs, fixed base operators offices, air carrier offices, and operations
offices.
3. The control tower also issues bulletins describing areas where they cannot provide ATC service due to
nonvisibility or other reasons.
4. A clearance must be obtained prior to taxiing on a runway, taking off, or landing during the hours an
Airport Traffic Control Tower is in operation.
5. A clearance must be obtained prior to crossing any runway. ATC will issue an explicit clearance for all
runway crossings.
6. When assigned a takeoff runway, A TC will first specify the runway, issue taxi instructions, and state any
hold short instructions or runway crossing clearances if the taxi route will cross a runway. This does not authorize
the aircraft to “enter” or “cross” the assigned departure runway at any point. In order to preclude
misunderstandings in radio communications, ATC will not use the word “cleared” in conjunction with
authorization for aircraft to taxi.
7. When issuing taxi instructions to any point other than an assigned takeoff runway, ATC will specify the
point to taxi to, issue taxi instructions, and state any hold short instructions or runway crossing clearances if the
taxi route will cross a runway.
NOTE−
ATC is required to obtain a readback from the pilot of all runway hold short instructions.
4−3−24 Airport Operations
AIM2/20/257/9/26 AIM
8. If a pilot is expected to hold short of a runway approach/departure ( Runway XX APPCH/Runway XX
DEP) hold area or ILS holding position (see FIG 2−3−15, Taxiways Located in Runway Approach Area), ATC
will issue instructions.
9. When taxi instructions are received from the controller, pilots should always read back:
(a) The runway assignment.
(b) Any clearance to enter a specific runway.
(c) Any instruction to hold short of a specific runway or line up and wait.
10. Controllers are required to request a readback of runway hold short assignment when it is not received
from the pilot/vehicle.
b. ATC clearances or instructions pertaining to taxiing are predicated on known traffic and known physical
airport conditions. Therefore, it is important that pilots clearly understand the clearance or instruction. Although
an ATC clearance is issued for tax iing purposes, when operating in accordance with the CFRs, it is the
responsibility of the pilot to avoid collision with other aircraft. Since “the pilot−in−command of an aircraft is
directly responsible for, and is the final authority as to, the operation of that aircraft” the pilot should obtain
clarification of any clearance or instruction which is not understood.
1. Good operating practice dictates that pilots acknowledge all runway crossing, hold short, or takeoff
clearances unless there is some misunderstanding, at which time the pilot should query the controller until the
clearance is understood.
NOTE−
Air traffic controllers are required to obtain from the pilot a readback of all runway hold short instructions.
2. Pilots operating a single pilot aircraft should monitor only assigned ATC communications after being
cleared onto the active runway for departure. Single pilot aircraft should not monitor other than ATC
communications until flight from Class B, Class C, or Class D surface area is completed. This same procedure
should be practiced from after receipt of the clearance for landing until the landing and taxi activities are
complete. Proper effective scanning for other aircraft, surface vehicles, or other objects should be continuously
exercised in all cases.
3. If the pilot is unfamiliar with the airport or for any reason confusion exists as to the correct taxi routing,
a request may be made for progressive taxi instructions which include step− by−step routing directions.
Progressive instructions may also be issued if the controller deems it necessary due to traffic or field conditions
(for example, construction or closed taxiways).
c. At those airports where the U.S. Government op erates the control tower and ATC has authorized
noncompliance with the requirement for two−way radio communications while operating within the Class B,
Class C, or Class D surface area, or at those airports where the U.S. Government does not operate the control
tower and radio communications cannot be established, pilots must obtain a clearance by visual light signal prior
to taxiing on a runway and prior to takeoff and landing.
d. The following phraseologies and procedures are used in radiotelephone communications with aeronautical
ground stations.
1. Request for taxi instructions prior to departure. State your aircraft identification, location, type of
operation planned (VFR or IFR), and the point of first intended landing.
EXAMPLE−
Aircraft: “Washington ground, Beechcraft One Three One Five Niner at hangar eight, ready to taxi, I−F−R to Chicago.”
Tower: “Beechcraft one three one five niner, Washington ground, runway two seven, taxi via taxiways Charlie and Delta,
hold short of runway three three left.”
Aircraft: “Beechcraft One Three One Five Niner, runway two seven, hold short of runway three three left.”
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2. Receipt of ATC clearance. ARTCC clearances are relayed to pilots by airport traffic controllers in the
following manner.
EXAMPLE−
Tower: “Beechcraft One Three One Five Niner, cleared to the Chicago Midway Airport via Victor Eight, maintain eight
thousand.”
Aircraft: “Beechcraft One Three One Five Niner, cleared to the Chicago Midway Airport via Victor Eight, maintain eight
thousand.”
NOTE−
Normally, an ATC IFR clearance is relayed to a pilot by the ground controller . At busy locations, however, pilots may be
instructed by the ground controller to “contact clearance delivery” on a frequency designated for this purpose. No
surveillance or control over the movement of traffic is exercised by this position of operation.
3. Request for taxi instructions after landing. State your aircraft identification, location, and that you
request taxi instructions.
EXAMPLE−
Aircraft: “Dulles ground, Beechcraft One Four Two Six One clearing runway one right on taxiway echo three, request
clearance to Page.”
Tower: “Beechcraft One Four Two Six One, Dulles ground, taxi to Page via taxiways echo three, echo one, and echo niner.”
or
Aircraft: “Orlando ground, Beechcraft One Four Two Six One clearing runway one eight left at taxiway bravo three, request
clearance to Page.”
Tower: “Beechcraft One Four Two Six One, Orlando ground, hold short of runway one eight right.”
Aircraft: “Beechcraft One Four Two Six One, hold short of runway one eight right.”
e. During ground operations, jet blast, prop wash, and rotor wash can cause damage and upsets if encountered
at close range. Pilots should consider the effects of jet blast, prop wash, and rotor wash on aircraft, vehicles, and
maintenance equipment during ground operations.
4−3−19. Taxi During Low Visibility
a. Pilots and aircraft operators should be constantly aware that during certain low visibility conditions the
movement of aircraft and vehicles on airports may not be visible to the tower controller. This may prevent visual
confirmation of an aircraft’s adherence to taxi instructions.
b. Of vital importance is the need for pilots to notify the controller when difficulties are encountered or at the
first indication of becoming disoriented. Pilots should proceed with extreme caution when taxiing toward the
sun. When vision difficulties are encountered pilots should immediately inform the controller.
c. Advisory Circular 120−57, Low Visibility Operations Surface Movement Guidance and Control System,
commonly known as LVOSMGCS (pronounced “LVO SMIGS”) describes an adequate example of a low
visibility taxi plan for any airport which has takeoff or landing operations in less than 1,200 feet runway visual
range (RVR) visibility conditions. These plans, which affect aircrew and vehicle operators, may incorporate
additional lighting, markings, and procedures to control airport surface traffic. They will be addressed at two
levels; operations less than 1,200 feet RVR to 500 feet RVR and operations less than 500 feet RVR.
NOTE−
Specific lighting systems and surface markings may be found in paragraph 2−1−10, Taxiway Lights, and paragraph 2−3−4,
Taxiway Markings.
d. When low visibility conditions exist, pilots should focus their entire attention on the safe operation of the
aircraft while it is moving. Checklists and nonessential communication should be withheld until the aircraft is
stopped and the brakes set.
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4−3−20. Standard Taxi Routes
a. Standard Taxi Routes (STRs) provide a standard, predictable taxi route from an origination point to a
termination point on the airport movement area. The use of STRs helps reduce frequency congestion and
streamline taxi procedures. STRs may be available at certain airports. Absent an STR Letter of Agreement
(LOA), issuance of an STR will be at the request of the pilot and discretion of ATC. STRs used under an LOA
are issued by ATC and are not required to be requested by the pilot.
b. STRs are available via two methods, (LOA) or publicly −available via the Domestic Notices website:
https://www.faa.gov/air_traffic/publications/domesticnotices/.
c. An LOA for STRs will be revised for updates and changes, including cancellation on an as−needed basis
with the operator. It is the responsibility of the operator to distribute changes to their flight crews.
d. An STR may be requested by a pilot or assigned at the discretion of ATC to the pilot of an operator with
an LOA STR. It is the responsibility of the pilot to request a full taxi clearance if not fully familiar with the STR.
e. A Letter to Airmen (LTA) will be issued by airport traffic control towers to announce availability, updates,
cancelation, or changes of publicly−available STRs with appropriate updates to the Domestic Notices website.
An LTA may include an airport diagram. The airport diagram will be labeled “not for navigation” and is not an
acceptable substitute for the most up−to−date airport diagrams. LTAs are available via the FAA NOTAM Search
website: https://notams.aim.faa.gov/notamSearch/.
f. Pilots request publicly−available STRs by stating the desired STR name (e.g., ATC facility, flight or aircraft
identification, location, request STR name). By requesting an STR, a pilot acknowledges full familiarity with
the STR. The issuance of a pilot−requested STR is at the discretion of ATC.
g. STRs contain the same characteristics and responsibilities:
1. Pilots should not request, and ATC may not issue STR instructions during low visibility Surface
Movement Guidance and Control System (SMGCS) operations.
2. It is the pilot’s responsibility to maintain familiarity and awareness of the most current versions of STRs,
as well as airport diagrams and charts prior to accepting an STR assignment.
3. If a pilot is unsure about the assigned STR procedure, the pilot is encouraged to either seek clarification
from ATC or decline the STR assignment.
4. Pilots who become disoriented during taxi should advise ATC immediately and request detailed taxi
instructions or other assistance.
5. An STR instruction does not constitute nor imply a clearance to cross a runway.
6. Unless otherwise stated by ATC, the issuance of an STR does not give an aircraft the right of way over
another taxiing aircraft.
7. Unless otherwise instructed by ATC, originating from, and terminating to a non−movement area as part
of an STR is at the discretion of the pilot in coordination with ramp control, if required.
8. If ATC instructs the pilot to deviate from an STR, ATC must issue detailed taxi instructions for the
remainder of the taxi.
9. Pilots are urged to exercise caution when accepting STR assignments, especially when STRs are used
or available at more than one airport in the same terminal area.
h. ATC may cancel, amend, or revise an STR as necessary. Any updates to publicly−available STRs will be
communicated via LTA with appropriate updates to the Domestic Notices website.
4−3−21. Exiting the Runway After Landing
The following procedures must be followed after landing and reaching taxi speed.
Airport Operations 4−3−27
AIM 2/20/253/15/077110.65R CHG 2AIM 7/9/26
a. Exit the runway without delay at the first available taxiway or on a taxiway as instructed by ATC. Pilots
must not exit the landing runway onto another runway unless authorized by ATC. At airports with an operating
control tower, pilots should not stop or reverse course on the runway without first obtaining ATC approval.
b. Taxi clear of the runway unless otherwise directed by ATC. An aircraft is considered clear of the runway
when all parts of the aircraft are past the runway edge and there are no restrictions to its continued movement
beyond the runway holding position markings. In the absence of ATC instructions, the pilot is expected to taxi
clear of the landing runway by taxiing beyond the runway holding position markings associated with the landing
runway, even if that requires the aircraft to protrude into or cross another taxiway or ramp area. Once all parts
of the aircraft have crossed the runway holding position markings, the pilot must hold unless further instructions
have been issued by ATC.
NOTE−
1. The tower will issue the pilot instructions which will permit the aircraft to enter another taxiway, runway, or ramp area
when required.
2. Guidance contained in subparagraphs a and b above is considered an integral part of the landing clearance and satisfies
the requirement of 14 CFR section 91.129.
c. Immediately change to ground control frequency when advised by the tower and obtain a taxi clearance.
NOTE−
1. The tower will issue instructions required to resolve any potential conflictions with other ground traffic prior to advising
the pilot to contact ground control.
2. Ground control will issue taxi clearance to parking. That clearance does not authorize the aircraft to “enter” or “cross”
any runways. Pilots not familiar with the taxi route should request specific taxi instructions from ATC.
4−3−22. Practice Instrument Approaches
a. Various air traffic incidents have indicated the necessity for adoption of measures to achieve more
organized and controlled operations where practice instrument approaches are conducted. Practice instrument
approaches are considered to be instrument approaches made by either a VFR aircraft not on an IFR flight plan
or an aircraft on an IFR flight plan. To achieve this and thereby enhance air safety, it is Air Traffic’s policy to
provide for separation of such operations at locations where approach control facilities are located and, as
resources permit, at certain other locations served by ARTCCs or parent approach control facilities. Pilot requests
to practice instrument approaches may be approved by ATC subject to traffic and workload conditions. Pilots
should anticipate that in some instances the controller may find it necessary to deny approval or withdraw
previous approval when traffic conditions warrant. It must be clearly understood, however, that even though the
controller may be providing separation, pilots on VFR flight plans are required to comply with basic VFR
weather minimums (14 CFR section 91. 155). Application of ATC procedur es or any action taken by the
controller to avoid traffic conflictions does not re lieve IFR and VFR pilots of their responsibility to
see−and−avoid other traffic while operating in VFR conditions (14 CFR section 91.113). In addition to the
normal IFR separation minimums (which includes visual separation) during VFR conditions, 500 feet vertical
separation may be applied between VFR aircraft and between a VFR aircraft and the IFR aircraft. Pilots not on
IFR flight plans desiring practice instrument approaches should always state ‘practice’ when making requests
to ATC. Controllers will instruct VFR aircraft requesting an instrument approach to maintain VFR. This is to
preclude misunderstandings between the pilot and controller as to the status of the aircraft. If pilots wish to
proceed in accordance with instrument flight rules, they must specifically request and obtain, an IFR clearance.
b. Before practicing an instrument approach, pilots should inform the approach control facility or the tower
of the type of practice approach they desire to make and how they intend to terminate it, i.e., full−stop landing,
touch−and−go, or missed or low approach maneuver. This information may be furnished progressively when
conducting a series of approaches. Pilots on an IFR flight plan, who have made a series of instrument approaches
to full stop landings should inform ATC when they make their final landing. The controller will control flights
practicing instrument approaches so as to ensure that they do not disrupt the flow of arriving and departing
itinerant IFR or VFR aircraft. The priority afforded itinerant aircraft over practice instrument approaches is not
4−3−28 Airport Operations
AIM2/20/257/9/26 AIM
intended to be so rigidly applied that it causes grossly inefficient application of services. A minimum delay to
itinerant traffic may be appropriate to allow an aircraft practicing an approach to complete that approach.
NOTE−
A clearance to land means that appropriate separation on the landing runway will be ensured. A landing clearance does
not relieve the pilot from compliance with any previously issued restriction.
c. At airports without a tower, pilots wishing to make practice instrument approaches should notify the facility
having control jurisdiction of the desired approach as indicated on the approach chart. All approach control
facilities and ARTCCs are required to publish a Letter to Airmen depicting those airports where they provide
standard separation to both VFR and IFR aircraft conducting practice instrument approaches.
d. The controller will provide approved separation between both VFR and IFR aircraft when authorization
is granted to make practice approaches to airports where an approach control facility is located and to certain
other airports served by approach control or an ARTCC. Controller responsibility for separation of VFR aircraft
begins at the point where the approach clearance becomes effective, or when the aircraft enters Class B or Class
C airspace, or a TRSA, whichever comes first.
e. VFR aircraft practicing instrument approaches are not automatically authorized to execute the missed
approach procedure. This authorization must be sp ecifically requested by the pilot and approved by the
controller. Where ATC procedures require application of IFR separation to VFR aircraft practicing instrument
approaches, separation will be provided throughout the procedure including the missed approach. Where no
separation services are provided during the practice approach, no separation services will be provided during the
missed approach.
f. Except in an emergency, aircraft cleared to practice instrument approaches must not deviate from the
approved procedure until cleared to do so by the controller.
g. At radar approach control locations when a full approach procedure (procedure turn, etc.,) cannot be
approved, pilots should expect to be vectored to a final approach course for a practice instrument approach which
is compatible with the general direction of traffic at that airport.
h. When granting approval for a practice instrument approach, the controller will usually ask the pilot to report
to the tower prior to or over the final approach fix inbound (nonprecision approaches) or over the outer marker
or fix used in lieu of the outer marker inbound (precision approaches).
i. When authorization is granted to conduct practice instrument approaches to an airport with a tower, but
where approved standard separation is not provided to aircraft conducting practice instrument approaches, the
tower will approve the practice approach, instruct the aircraft to maintain VFR and issue traffic information, as
required.
j. When an aircraft notifies a FSS providing Local Airport Advisory to the airport concerned of the intent to
conduct a practice instrument approach and whether or not separation is to be provided, the pilot will be instructed
to contact the appropriate facility on a specified frequency prior to initiating the approach. At airports where
separation is not provided, the FSS will acknowledge the message and issue known traffic information but will
neither approve or disapprove the approach.
k. Pilots conducting practice instrument approaches should be particularly alert for other aircraft operating
in the local traffic pattern or in proximity to the airport.
4−3−23. Option Approach
The “Cleared for the Option” procedure will permit an instructor, flight examiner or pilot the option to make a
touch−and−go, low approach, missed approach, stop−and−go, or full stop landing. This procedure can be very
beneficial in a training situation in that neither the student pilot nor examinee would know what maneuver would
be accomplished. The pilot should make a request for this procedure passing the final approach fix inbound on
an instrument approach or entering downwind for a VFR traffic pattern. After ATC approval of the option, the
pilot should inform ATC as soon as possible of any delay on the runway during their stop-and-go or full stop
Airport Operations 4−3−29
AIM 2/20/253/15/077110.65R CHG 2AIM 7/9/26
landing. The advantages of this procedure as a training aid are that it enables an instructor or examiner to obtain
the reaction of a trainee or examinee under changing conditions, the pilot would not have to discontinue an
approach in the middle of the procedure due to student error or pilot proficiency requirements, and finally it
allows more flexibility and economy in training programs. This procedure will only be used at those locations
with an operational control tower and will be subject to ATC approval.
4−3−24. Use of Aircraft Lights
a. Aircraft position lights are required to be lighted on aircraft operated on the surface and in flight from sunset
to sunrise. In addition, aircraft equipped with an anti −collision light system are required to operate that light
system during all types of operations (day and night). However, during any adverse meteorological conditions,
the pilot−in−command may determine that the anti−collision lights should be turned off when their light output
would constitute a hazard to safety (14 CFR section 91.209). Supplementary strobe lights should be turned off
on the ground when they adversely affect ground personnel or other pilots, and in flight when there are adverse
reflection from clouds.
b. An aircraft anti−collision light system can use one or more rotating beacons and/or strobe lights, be colored
either red or white, and have different (higher than minimum) intensities when compared to other aircraft. Many
aircraft have both a rotating beacon and a strobe light system.
c. The FAA has a voluntary pilot safety program, Operation Lights On, to enhance the see−and−avoid concept.
Pilots are encouraged to turn on their landing lights during takeoff; i.e., either after takeoff clearance has been
received or when beginning takeoff roll. Pilots are further encouraged to turn on their landing lights when
operating below 10,000 feet, day or night, especially when operating within 10 miles of any airport, or in
conditions of reduced visibility and in areas where flocks of birds may be expected, i.e., coastal areas, lake areas,
around refuse dumps, etc. Although turning on aircraft lights does enhance the see−and−avoid concept, pilots
should not become complacent about keeping a sharp lookout for other aircraft. Not all aircraft are equipped with
lights and some pilots may not have their lights turned on. Aircraft manufacturer’s recommendations for
operation of landing lights and electrical systems should be observed.
d. Prop and jet blast forces generated by large aircraft have overturned or damaged several smaller aircraft
taxiing behind them. To avoid similar results, and in the interest of preventing upsets and injuries to ground
personnel from such forces, the FAA recommends that air carriers and commercial operators turn on their
rotating beacons anytime their aircraft engines are in operation. General aviation pilots using rotating beacon
equipped aircraft are also encouraged to participate in this program which is designed to alert others to the
potential hazard. Since this is a voluntary program, exercise caution and do not rely solely on the rotating beacon
as an indication that aircraft engines are in operation.
e. Prior to commencing taxi, it is recommended to turn on navigation, position, anti-collision, and logo lights
(if equipped). To signal intent to other pilots, consider turning on the taxi light when the aircraft is moving or
intending to move on the ground, and turning it off when stopped or yielding to other ground traffic. Strobe lights
should not be illuminated during taxi if they will adversely affect the vision of other pilots or ground personnel.
f. At the discretion of the pilot-in-command, all exterior lights should be illuminated when taxiing on or across
any runway. This increases the conspicuousness of the aircraft to controllers and other pilots approaching to land,
taxiing, or crossing the runway. Pilots should comply with any equipment operating limitations and consider the
effects of landing and strobe lights on other aircraft in their vicinity.
g. When entering the departure runway for takeoff or to “line up and wait,” all lights, except for landing lights,
should be illuminated to make the aircraft conspicuous to ATC and other aircraft on approach. Landing lights
should be turned on when takeoff clearance is received or when commencing takeoff roll at an airport without
an operating control tower.
4−3−25. Flight Inspection/‘Flight Check’ Aircraft in Terminal Areas
a. Flight check is a call sign used to alert pilots and air traffic controllers when a FAA aircraft is engaged in
flight inspection/certification of NA V AIDs and flight procedures. Flight check aircraft fly preplanned high/low
4−3−30 Airport Operations
AIM2/20/257/9/26 AIM
altitude flight patterns such as grids, orbits, DME arcs, and tracks, including low passes along the full length of
the runway to verify NA V AID performance.
b. Pilots should be especially watchful and avoid the flight paths of any aircraft using the call sign “Flight
Check.” These flights will normally receive special handling from ATC. Pilot patience and cooperation in
allowing uninterrupted recordings can significantly help expedite flight inspections, minimize costly, repetitive
runs, and reduce the burden on the U.S. taxpayer.
4−3−26. Hand Signals
FIG 4−3−11
Signalman Directs Towing
SIGNALMANSIGNALMAN
Airport Operations 4−3−31
AIM 2/20/253/15/077110.65R CHG 2AIM 7/9/26
FIG 4−3−12
Signalman’s Position
SIGNALMANSIGNALMAN
FIG 4−3−13
All Clear
(O.K.)
4−3−32 Airport Operations
AIM2/20/257/9/26 AIM
FIG 4−3−14
Start Engine
POINT
TO
ENGINE
TO BE
STARTED
FIG 4−3−15
Pull Chocks
Airport Operations 4−3−33
AIM 2/20/253/15/077110.65R CHG 2AIM 7/9/26
FIG 4−3−16
Proceed Straight Ahead
FIG 4−3−17
Left Turn
4−3−34 Airport Operations
AIM2/20/257/9/26 AIM
FIG 4−3−18
Right Turn
FIG 4−3−19
Slow Down
Airport Operations 4−3−35
AIM 2/20/253/15/077110.65R CHG 2AIM 7/9/26
FIG 4−3−20
Flagman Directs Pilot
FIG 4−3−21
Insert Chocks
4−3−36 Airport Operations
AIM2/20/257/9/26 AIM
FIG 4−3−22
Cut Engines
FIG 4−3−23
Night Operation
Use same hand movements
as day operation
Airport Operations 4−3−37
AIM 2/20/253/15/077110.65R CHG 2AIM 7/9/26
FIG 4−3−24
Stop
4−3−27. Operations at Uncontrolled Airports With Automated Surface Observing System
(ASOS)/Automated Weather Observing System (AWOS)
a. Many airports throughout the National Airspace System are equipped with either ASOS or AWOS. At most
airports with an operating control tower or human observer, the weather will be available to you in an Aviation
Routine Weather Report (METAR) hourly or special observation format on the Automatic Terminal Information
Service (ATIS) or directly transmitted from the controller/observer.
b. At uncontrolled airports that are equipped with ASOS/AWOS with ground−to−air broadcast capability, the
one−minute updated airport weather should be available to you within approximately 25 NM of the airport below
10,000 feet. The frequency for the weather broadcast will be published on sectional charts and in the Chart
Supplement. Some part −time towered airports may also broadcast the automated weather on their ATIS
frequency during the hours that the tower is closed.
c. Controllers issue SVFR or IFR clearances based on pilot request, known traffic and reported weather, i.e.,
METAR/Nonroutine (Special) Aviation Weather Report (SPECI) observations, when they are available. Pilots
have access to more current weather at uncontrolled ASOS/AWOS airports than do the controllers who may be
located several miles away. Controllers will rely on the pilot to determine the current airport weather from the
ASOS/AWOS. All aircraft arriving or departing an ASOS/AWOS equipped uncontrolled airport should monitor
the airport weather frequency to ascertain the status of the airspace. Pilots in Class E airspace must be alert for
changing weather conditions which may affect the status of the airspace from IFR/VFR. If ATC service is
required for IFR/SVFR approach/departure or requested for VFR service, the pilot should advise the controller
that he/she has received the one−minute weather and state his/her intentions.
EXAMPLE−
“I have the (airport) one−minute weather, request an ILS Runway 14 approach.”
REFERENCE−
AIM, Para 7−1−10, Weather Observing Programs.
4−3−38 Airport Operations
2/20/25 AIM
Section 4. ATC Clearances and Aircraft Separation
4−4−1. Clearance
a. A clearance issued by ATC is predicated on known traffic and known physical airport conditions. An ATC
clearance means an authorization by ATC, for the purpose of preventing collision between known aircraft, for
an aircraft to proceed under specified conditions within controlled airspace. IT IS NOT AUTHORIZATION
FOR A PILOT TO DEVIATE FROM ANY RULE, REGULATION, OR MINIMUM ALTITUDE NOR TO
CONDUCT UNSAFE OPERATION OF THE AIRCRAFT.
b. 14 CFR section 91.3(a) states: “The pilot−in−command of an aircraft is directly responsible for, and is the
final authority as to, the operation of that aircraft.” If ATC issues a clearance that would cause a pilot to deviate
from a rule or regulation, or in the pilot’s opinion, would place the aircraft in jeopardy, IT IS THE PILOT’S
RESPONSIBILITY TO REQUEST AN AMENDED CLEARANCE. Similarly, if a pilot prefers to follow a
different course of action, such as make a 360 degree turn for spacing to follow traffic when established in a
landing or approach sequence, land on a different runway, takeoff from a different intersection, takeoff from the
threshold instead of an intersection, or delay operation, THE PILOT IS EXPECTED TO INFORM ATC
ACCORDINGLY . When the pilot requests a different course of action, however, the pilot is expected to
cooperate so as to preclude disruption of traffic flow or creation of conflicting patterns. The pilot is also expected
to use the appropriate aircraft call sign to acknowledge all ATC clearances, frequency changes, or advisory
information.
c. Each pilot who deviates from an ATC clearance in response to a Traffic Alert and Collision Avoidance
System resolution advisory must notify ATC of that deviation as soon as possible.
REFERENCE−
Pilot/Controller Glossary Term− Traffic Alert and Collision Avoidance System.
d. When weather conditions permit, during the time an IFR flight is operating, it is the direct responsibility
of the pilot to avoid other aircraft since VFR flights may be operating in the same area without the knowledge
of ATC. Traffic clearances provide standard separation only between IFR flights.
4−4−2. Clearance Prefix
A clearance, control information, or a response to a request for information originated by an ATC facility and
relayed to the pilot through an air−to−ground communication station will be prefixed by “ATC clears,” “ATC
advises,” or “ATC requests.”
4−4−3. Clearance Items
ATC clearances normally contain the following:
a. Clearance Limit. The traffic clearance issued prior to departure will normally authorize flight to the
airport of intended landing. Many airports and associated NA V AIDs are collocated with the same name and/or
identifier, so care should be exercised to ensure a clear understanding of the clearance limit. When the clearance
limit is the airport of intended landing, the clearance should contain the airport name followed by the word
“airport.” Under certain conditions, a clearance limit may be a NA V AID or other fix. When the clearance limit
is a NA V AID, intersection, or waypoint and the type is known, the clearance should contain type. Under certain
conditions, at some locations a short−range clearance procedure is utilized whereby a clearance is issued to a fix
within or just outside of the terminal area and pilots are advised of the frequency on which they will receive the
long−range clearance direct from the center controller.
b. Departure Procedure. Headings to fly and altitude restrictions may be issued to separate a departure from
other air traffic in the terminal area. Where the volume of traffic warrants, DPs have been developed.
ATC Clearances and Aircraft Separation 4−4−1
AIM 2/20/25
REFERENCE−
AIM, Para 5−2−6, Abbreviated IFR Departure Clearance (Cleared. . .as Filed) Procedures.
AIM, Para 5−2−9, Instrument Departure Procedures (DP) − Obstacle Departure Procedures (ODP) and Standard Instrument Departures (SID).
c. Route of Flight.
1. Clearances are normally issued for the altitude or flight level and route filed by the pilot. However, due
to traffic conditions, it is frequently necessary for ATC to specify an altitude or flight level or route different from
that requested by the pilot. In addition, flow patterns have been established in certain congested areas or between
congested areas whereby traffic capacity is increased by routing all traffic on preferred routes. Information on
these flow patterns is available in offices where preflight briefing is furnished or where flight plans are accepted.
2. When required, air traffic clearances include data to assist pilots in identifying radio reporting points. It
is the responsibility of pilots to notify ATC immediately if their radio equipment cannot receive the type of signals
they must utilize to comply with their clearance.
d. Altitude Data.
1. The altitude or flight level instructions in an ATC clearance normally require that a pilot “MAINTAIN”
the altitude or flight level at which the flight will operate when in controlled airspace. Altitude or flight level
changes while en route should be requested prior to the time the change is desired.
2. When possible, if the altitude assigned is different from the altitude requested by the pilot, ATC will
inform the pilot when to expect climb or descent clearance or to request altitude change from another facility.
If this has not been received prior to crossing the boundary of the ATC facility’s area and assignment at a different
altitude is still desired, the pilot should reinitiate the request with the next facility.
3. The term “cruise” may be used instead of “MAINTAIN” to assign a block of airspace to a pilot from the
minimum IFR altitude up to and including the altitude specified in the cruise clearance. The pilot may level off
at any intermediate altitude within this block of airspace. Climb/descent within the block is to be made at the
discretion of the pilot. However, once the pilot starts descent and verbally reports leaving an altitude in the block,
the pilot may not return to that altitude without additional ATC clearance.
REFERENCE−
Pilot/Controller Glossary Term− Cruise.
e. Holding Instructions.
1. Whenever an aircraft has been cleared to a fix other than the destination airport and delay is expected,
it is the responsibility of the ATC controller to issue complete holding instructions (unless the pattern is charted),
an EFC time, and a best estimate of any additional en route/terminal delay.
2. If the holding pattern is charted and the controller doesn’t issue complete holding instructions, the pilot
is expected to hold as depicted on the appropriate chart. When the pattern is charted, the controller may omit all
holding instructions except the charted holding direction and the statement AS PUBLISHED, e.g., “HOLD EAST
AS PUBLISHED.” Controllers must always issue complete holding instructions when pilots request them.
NOTE−
Only those holding patterns depicted on U.S. government or commercially produced charts which meet F AA requirements
should be used.
3. If no holding pattern is charted and holding instructions have not been issued, the pilot should ask ATC
for holding instructions prior to reaching the fix. This procedure will eliminate the possibility of an aircraft
entering a holding pattern other than that desired by ATC. If unable to obtain holding instructions prior to
reaching the fix (due to frequency congestion, stuck microphone, etc.), hold in a standard pattern on the course
on which you approached the fix and request further clearance as soon as possible. In this event, the altitude/flight
level of the aircraft at the clearance limit will be protected so that separation will be provided as required.
4. When an aircraft is 3 minutes or less from a clearance limit and a clearance beyond the fix has not been
received, the pilot is expected to start a speed reduction so that the aircraft will cross the fix, initially, at or below
the maximum holding airspeed.
4−4−2 ATC Clearances and Aircraft Separation
2/20/25 AIM
5. When no delay is expected, the controller should issue a clearance beyond the fix as soon as possible and,
whenever possible, at least 5 minutes before the aircraft reaches the clearance limit.
6. Pilots should report to ATC the time and altitude/flight level at which the aircraft reaches the clearance
limit and report leaving the clearance limit.
NOTE−
In the event of two−way communications failure, pilots are required to comply with 14 CFR section 91.185.
4−4−4. Amended Clearances
a. Amendments to the initial clearance will be issued at any time an air traffic controller deems such action
necessary to avoid possible confliction between aircraft. Clearances will require that a flight “hold” or change
altitude prior to reaching the point where standard separation from other IFR traffic would no longer exist.
NOTE−
Some pilots have questioned this action and requested “traffic information” and were at a loss when the reply indicated “no
traffic report.” In such cases the controller has taken action to prevent a traffic confliction which would have occurred at
a distant point.
b. A pilot may wish an explanation of the handling of the flight at the time of occurrence; however, controllers
are not able to take time from their immediate control duties nor can they afford to overload the ATC
communications channels to furnish explanations. Pilots may obtain an explanation by directing a letter or
telephone call to the chief controller of the facility involved.
c. Pilots have the privilege of requesting a different clearance from that which has been issued by ATC if they
feel that they have information which would make another course of action more practicable or if aircraft
equipment limitations or company procedures forbid compliance with the clearance issued.
4−4−5. Coded Departure Route (CDR)
a. CDRs provide air traffic control a rapid means to reroute departing aircraft when the filed route is
constrained by either weather or congestion.
b. CDRs consist of an eight−character designator that represents a route of flight. The first three alphanumeric
characters represent the departure airport, characters four through six represent the arrival airport, and the last
two characters are chosen by the overlying ARTCC. For example, PITORDN1 is an alternate route from
Pittsburgh to Chicago. Participating aircrews may then be re −cleared by air traffic control via the CDR
abbreviated clearance, PITORDN1.
c. CDRs are updated on the 56 day charting cycle. Participating aircrews must ensure that their CDR is current.
d. Traditionally, CDRs have been used by air transport companies that have signed a Memorandum of
Agreement with the local air traffic control facility. General aviation customers who wish to participate in the
program may now enter “CDR Capable” in the remarks section of their flight plan.
e. When “CDR Capable” is entered into the remarks section of the flight plan the general aviation customer
communicates to ATC the ability to decode the current CDR into a flight plan route and the willingness to fly
a different route than that which was filed.
4−4−6. Special VFR Clearances
a. An A TC clearance must be obtained prior to operating within a Class B, Class C, Class D, or Class E surface
area when the weather is less than that required for VFR flight. A VFR pilot may request and be given a clearance
to enter, leave, or operate within most Class D and Class E surface areas and some Class B and Class C surface
areas in special VFR conditions, traffic permitting, and providing such flight will not delay IFR operations. All
special VFR flights must remain clear of clouds. The visibility requirements for special VFR aircraft (other than
helicopters) are:
ATC Clearances and Aircraft Separation 4−4−3
AIM 2/20/25
1. At least 1 statute mile flight visibility for operations within Class B, Class C, Class D, and Class E surface
areas.
2. At least 1 statute mile ground visibility if taking off or landing. If ground visibility is not reported at that
airport, the flight visibility must be at least 1 statute mile.
3. The restrictions in subparagraphs 1 and 2 do not apply to helicopters. Helicopters must remain clear of
clouds and may operate in Class B, Class C, Class D, and Class E surface areas with less than 1 statute mile
visibility.
b. When a control tower is located within the Class B, Class C, or Class D surface area, requests for clearances
should be to the tower. In a Class E surface area, a clearance may be obtained from the nearest tower, FSS, or
center.
c. It is not necessary to file a complete flight plan with the request for clearance, but pilots should state their
intentions in sufficient detail to permit ATC to fit their flight into the traffic flow. The clearance will not contain
a specific altitude as the pilot must remain clear of clouds. The controller may require the pilot to fly at or below
a certain altitude due to other traffic, but the altitude specified will permit flight at or above the minimum safe
altitude. In addition, at radar locations, flights may be vectored if necessary for control purposes or on pilot
request.
NOTE−
The pilot is responsible for obstacle or terrain clearance.
REFERENCE−
14 CFR Section 91.119, Minimum safe altitudes: General.
d. Special VFR clearances are effective within Class B, Class C, Class D, and Class E surface areas only. A TC
does not provide separation after an aircraft leaves the Class B, Class C, Class D, or Class E surface area on a
special VFR clearance.
e. Special VFR operations by fixed−wing aircraft are prohibited in some Class B and Class C surface areas
due to the volume of IFR traffic. A list of these Class B and Class C surface areas is contained in 14 CFR part 91,
Appendix D, Section 3. They are also depicted on sectional aeronautical charts.
f. ATC provides separation between Special VFR flights and between these flights and other IFR flights.
g. Special VFR operations by fixed−wing aircraft are prohibited between sunset and sunrise unless the pilot
is instrument rated and the aircraft is equipped for IFR flight.
h. Pilots arriving or departing an uncontrolled airport that has automated weather broadcast capability
(ASOS/AWOS) should monitor the broadcast frequency, advise the controller that they have the “one−minute
weather” and state intentions prior to operating within the Class B, Class C, Class D, or Class E surface areas.
REFERENCE−
Pilot/Controller Glossary Term− One−minute Weather.
4−4−7. Pilot Responsibility upon Clearance Issuance
a. Record ATC clearance. When conducting an IFR operation, make a written record of your clearance. The
specified conditions which are a part of your air traffic clearance may be somewhat different from those included
in your flight plan. Additionally, ATC may find it necessary to ADD conditions, such as particular departure
route. The very fact that ATC specifies different or additional conditions means that other aircraft are involved
in the traffic situation.
b. ATC Clearance/Instruction Readback. Pilots of airborne aircraft should read back those parts of ATC
clearances and instructions containing altitude assignments, vectors, or runway assignments as a means of
mutual verification. The read back of the “numbers” serves as a double check between pilots and controllers and
reduces the kinds of communications errors that occur when a number is either “misheard” or is incorrect.
1. Include the aircraft identification in all readbacks and acknowledgments. This aids controllers in
determining that the correct aircraft received the clearance or instruction. The requirement to include aircraft
4−4−4 ATC Clearances and Aircraft Separation
2/20/25 AIM
identification in all readbacks and acknowledgements becomes more important as frequency congestion
increases and when aircraft with similar call signs are on the same frequency.
EXAMPLE−
“Climbing to Flight Level three three zero, United Twelve” or “November Five Charlie Tango, roger , cleared to land runway
nine left.”
2. Read back altitudes, altitude restrictions, and vectors in the same sequence as they are given in the
clearance or instruction.
3. Altitudes contained in charted procedures, such as DPs, instrument approaches, etc., should not be read
back unless they are specifically stated by the controller.
4. Initial read back of a taxi, departure or landing clearance should include the runway assignment,
including left, right, center, etc. if applicable.
c. It is the responsibility of the pilot to accept or refuse the clearance issued.
4−4−8. IFR Clearance VFR −on−top
a. A pilot on an IFR flight plan operating in VFR weather conditions, may request VFR−on−top in lieu of an
assigned altitude. This permits a pilot to select an altitude or flight level of their choice (subject to any ATC
restrictions.)
b. Pilots desiring to climb through a cloud, haze, smoke, or other meteorological formation and then either
cancel their IFR flight plan or operate VFR-on-top may request a climb to VFR-on-top. The ATC authorization
must contain either a top report or a statement that no top report is available, and a request to report reaching
VFR-on-top. Additionally, the ATC authorization may contain a clearance limit, routing and an alternative
clearance if VFR−on−top is not reached by a specified altitude.
c. A pilot on an IFR flight plan, operating in VFR conditions, may request to climb/descend in VFR
conditions.
d. ATC may not authorize VFR −on−top/VFR conditions operations unless the pilot requests the VFR
operation or a clearance to operate in VFR conditions will result in noise abatement benefits where part of the
IFR departure route does not conform to an FAA approved noise abatement route or altitude.
e. When operating in VFR conditions with an ATC authorization to “maintain VFR−on−top/maintain VFR
conditions” pilots on IFR flight plans must:
1. Fly at the appropriate VFR altitude as prescribed in 14 CFR section 91.159.
2. Comply with the VFR visibility and distance from cloud criteria in 14 CFR section 91.155 (Basic VFR
Weather Minimums).
3. Comply with instrument flight rules that are applicable to this flight; i.e., minimum IFR altitudes,
position reporting, radio communications, course to be flown, adherence to ATC clearance, etc.
NOTE−
Pilots should advise ATC prior to any altitude change to ensure the exchange of accurate traffic information.
f. ATC authorization to “maintain VFR−on−top” is not intended to restrict pilots so that they must operate only
above an obscuring meteorological formation (layer). Instead, it permits operation above, below, between layers,
or in areas where there is no meteorological obscuration. It is imperative, however, that pilots understand that
clearance to operate “VFR−on−top/VFR conditions” does not imply cancellation of the IFR flight plan.
g. Pilots operating VFR−on−top/VFR conditions may receive traffic information from ATC on other pertinent
IFR or VFR aircraft. However, aircraft operating in Class B airspace/TRSAs must be separated as required by
FAA Order JO 7110.65, Air Traffic Control.
NOTE−
When operating in VFR weather conditions, it is the pilot’ s responsibility to be vigilant so as to see−and−avoid other aircraft.
ATC Clearances and Aircraft Separation 4−4−5
AIM 2/20/25
h. ATC will not authorize VFR or VFR−on−top operations in Class A airspace.
REFERENCE−
AIM, Para 3−2−2, Class A Airspace.
4−4−9. VFR/IFR Flights
A pilot departing VFR, either intending to or needing to obtain an IFR clearance en route, must be aware of the
position of the aircraft and the relative terrain/ obstructions. When accepting a clearance below the
MEA/MIA/MV A/OROCA, pilots are responsible for their own terrain/obstruction clearance until reaching the
MEA/MIA/MV A/OROCA. If pilots are unable to maintain terrain/obstruction clearance, the controller should
be advised and pilots should state their intentions.
NOTE−
OROCA is a published altitude which provides 1,000 feet of terrain and obstruction clearance in the US (2,000 feet of
clearance in designated mountainous areas). These altitudes are not assessed for NAVAID signal coverage, air traffic
control surveillance, or communications coverage, and are published for general situational awareness, flight planning and
in−flight contingency use.
4−4−10. Adherence to Clearance
a. When air traffic clearance has been obtained under either visual or instrument flight rules, the
pilot−in−command of the aircraft must not deviate from the provisions thereof unless an amended clearance is
obtained. When ATC issues a clearance or instruction, pilots are expected to execute its provisions upon receipt.
ATC, in certain situations, will include the word “IMMEDIATELY” in a clearance or instruction to impress
urgency of an imminent situation and expeditious compliance by the pilot is expected and necessary for safety.
The addition of a VFR or other restriction; i.e., climb or descent point or time, crossing altitude, etc., does not
authorize a pilot to deviate from the route of flight or any other provision of the ATC clearance.
b. When a heading is assigned or a turn is requested by ATC, pilots are expected to promptly initiate the turn,
to complete the turn, and maintain the new heading unless issued additional instructions.
c. The term “AT PILOT’S DISCRETION” included in the altitude information of an ATC clearance means
that A TC has offered the pilot the option to start climb or descent when the pilot wishes, is authorized to conduct
the climb or descent at any rate, and to temporarily level off at any intermediate altitude as desired. However,
once the aircraft has vacated an altitude, it may not return to that altitude.
d. When ATC has not used the term “AT PILOT’S DISCRETION” nor imposed any climb or descent
restrictions, pilots should initiate climb or descent promptly on acknowledgement of the clearance. Descend or
climb at an optimum rate consistent with the operating characteristics of the aircraft to 1,000 feet above or below
the assigned altitude, and then attempt to descend or climb at a rate of between 500 and 1,500 fpm until the
assigned altitude is reached. If at anytime the pilot is unable to climb or descend at a rate of at least 500 feet a
minute, advise ATC. If it is necessary to level off at an intermediate altitude during climb or descent, advise ATC,
except when leveling off at 10,000 feet MSL on descent, or 2,500 feet above airport elevation (prior to entering
a Class C or Class D surface area), when required for speed reduction.
REFERENCE−
14 CFR section 91.117.
NOTE−
Leveling off at 10,000 feet MSL on descent or 2,500 feet above airport elevation (prior to entering a Class C or Class D
surface area) to comply with 14 CFR section 91.117 airspeed restrictions is commonplace. Controllers anticipate this action
and plan accordingly. Leveling off at any other time on climb or descent may seriously affect air traffic handling by ATC.
Consequently, it is imperative that pilots make every effort to fulfill the above expected actions to aid ATC in safely handling
and expediting traffic.
e. If the altitude information of an ATC DESCENT clearance includes a provision to “CROSS (fix) AT” or
“AT OR ABOVE/BELOW (altitude),” the manner in which the descent is executed to comply with the crossing
altitude is at the pilot’s discretion. This authorization to descend at pilot’s discretion is only applicable to that
4−4−6 ATC Clearances and Aircraft Separation