Figure 1-8. Examples of non-standard takeoff minimums for Colorado Springs, Colorado.
SE-2, 29 JUL 2010 to 26 AUG 2010
NOT FOR NAVIGATION
2010 to 26 AUG 2010
rapidly changing aviation technology and environment
through the regulatory process. Safety regulations
would be extremely complex and unwieldy if all possible
variations and situations were addressed by regulation.
Instead, the safety standards established by regulation
should usually have a broad application that allows varying
acceptable methods of compliance. The OpSpecs provide
an effective method for establishing safety standards that
address a wide range of variables. In addition, OpSpecs
can be adapted to a specific certificate holder or operator’s
class and size of aircraft and type and kinds of operations.
OpSpecs can be tailored to suit an individual certificate
holder or operator’s needs.
Part 121 and Part 135 certificate holders have the ability,
through the use of approved OpSpecs, to use lower-than
standard takeoff minimums. Depending on the equipment
installed in a specific type of aircraft, the crew training, and
the type of equipment installed at a particular airport, these
operators can depart from appropriately equipped runways
with as little as 300 feet RVR. Additionally, OpSpecs outline
provisions for approach minimums, alternate airports, and
weather services in Volume 3 of FAA Order 8900.1, Flight
Standards Information Management System (FSIMS).
SE-2, 29 JUL 2010 to 26 AUG 2010
Figure 1-9. Examples of weather information of various flight
information publications (FLIP).
Ceiling and Visibility Requirements
All takeoffs and departures have visibility minimums (some
may have minimum ceiling requirements) incorporated
into the procedure. There are a number of methods to
report visibility and a variety of ways to distribute these
reports, including automated weather observations. Flight
crews should always check the weather, including ceiling
and visibility information, prior to departure. Never launch
an IFR flight without obtaining current visibility information
immediately prior to departure. Further, when ceiling and
visibility minimums are specified for IFR departure, both
are applicable.
Weather reporting stations for specific airports across
the country can be located by reviewing the CS. Weather
sources along with their respective phone numbers and
frequencies are listed by airport. Frequencies for weather
sources, such as Automatic Terminal Information Service
(ATIS), Digital Automatic Terminal Information Service
(D-ATIS), Automated Weather Observing System (AWOS),
Automated Surface Observing System (ASOS), and FAA
Automated Flight Service Station (AFSS) are published on
approach charts as well. [Figure 1-9]
Visibility
Visibility is the ability, as determined by atmospheric
conditions and expressed in units of distance, to see
and identify prominent unlighted objects by day and
prominent lighted objects by night. Visibility is reported
as statute miles, hundreds of feet, or meters.
Prevailing Visibility
Prevailing visibility is the greatest horizontal visibility
equaled or exceeded throughout at least half the horizon
circle, which need not necessarily be continuous. Prevailing
visibility is reported in statute miles or fractions of miles.
Runway Visibility Value (RVV)
Runway visibility value is the visibility determined for a
particular runway by a transmissometer. A meter provides
Conversion
RVR (feet) Visibility (sm)
1,600 1/4
2,400 1/2
3,200 5/8
4,000 3/4
4,500 7/8
5,000 1
6,000 11/4
Figure 1-10. RVR conversion table.
continuous indication of the visibility (reported in statute
miles or fractions of miles) for the runway. RVV is used in lieu
of prevailing visibility in determining minimums for a particular
runway.
Tower Visibility
Tower visibility is the prevailing visibility determined from
the airport traffic control tower at locations that also report
the surface visibility.
Runway Visual Range (RVR)
Runway visual range is an instrumentally derived value,
based on standard calibrations, that represents the
horizontal distance a pilot sees down the runway from the
approach end. It is based on the sighting of either high
intensity runway lights or on the visual contrast of other
targets, whichever yields the greater visual range. RVR, in
contrast to prevailing or runway visibility, is based on what
a pilot in a moving aircraft should see looking down the
runway. RVR is horizontal visual range, not slant visual range.
RVR is reported in hundreds of feet, so the values must be
converted to SM if the visibility in SM is not reported. [Figure
1-10] It is based on the measurement of a transmissometer
made near the touchdown point of the instrument runway
and is reported in hundreds of feet. RVR is used in lieu of
RVV and/or prevailing visibility in determining minimums
for a particular runway.
Types of RVR
The following are types of RVR that may be used:
• Touchdown RVR—the RVR visibility readout values
obtained from RVR equipment serving the runway
touchdown zone.
• Mid-RVR—the RVR readout values obtained from
RVR equipment located near the runway midpoint .
• Rollout RVR—the RVR readout values obtained from
RVR equipment located nearest the rollout end of
the runway.
• Far End RVR—when four RVR visibility sensors (VS)
are installed, the far end RVR VS is the touchdown
RVR VS on the reciprocal runway. The far end sensor
will serve as additional information.
RVR is the primary visibility measurement used by Part
121 and Part 135 operators with specific visibility reports
and controlling values outlined in their respective OpSpecs.
Under their OpSpecs agreements, the operator must have
specific, current RVR reports, if available, to proceed with an
instrument departure. OpSpecs also outline which visibility
report is controlling in various departure scenarios.
Figure 1-11. AWSS installation at Driggs-Reed, Idaho.
Adequate Visual Reference
Another set of lower-than-standard takeoff minimums is
available to Part 121 and Part 135 operations as outlined in
their respective OpSpecs document. When certain types of
visibility reports are unavailable or specific equipment is out
of service, the flight can still depart the airport if the pilot
can maintain adequate visual reference. An appropriate
visual aid must be available to ensure the takeoff surface
can be continuously identified, and directional control can
be maintained throughout the takeoff run. Appropriate
visual aids include high intensity runway lights, runway
centerline lights, runway centerline markings, or other
runway lighting and markings. With adequate visual
references and appropriate OpSpec approval, commercial
operators may take off with a visibility of 1600 RVR or ¼
SM.
Ceilings
Ceiling is the height above the earth’s surface of the lowest
layer of clouds or obscuring phenomena that is reported as
broken, overcast, or obscuration and not classified as thin
or partial.
Automated Weather Systems
An automated weather system consists of any of the
automated weather sensor platforms that collect weather
data at airports and disseminate the weather information
via radio and/or landline. The systems consist of the ASOS/
Automated Weather Sensor System (AWSS) and the AWOS.
Figure 1-12. CS entry for an AWOS station.
SAMPLE NOT FOR ACTUAL USE
WEATHER DATA SOURCES: AWOS-3 119.675 (704) 735-6954.
AWOS/ASOS/AWSS information
These systems are installed and maintained at airports
across the United States by both government (FAA and
National Weather Service (NWS)) and private entities. They
are relatively inexpensive to operate because they require
no outside observer, and they provide invaluable weather
information for airports without operating control towers.
[Figure 1-11]
AWOS and ASOS/AWSS offer a wide variety of capabilities
and progressively broader weather reports. Automated
systems typically transmit weather every one to two
minutes so the most up-to-date weather information is
constantly broadcast. Basic AWOS includes only altimeter
setting, wind speed, wind direction, temperature, and dew
point information. More advanced systems, such as the
ASOS/AWSS and AWOS-3, are able to provide additional
information, such as wind speed, wind gust, wind direction,
variable wind direction, temperature, dew point, altimeter
setting, and density altitude. ASOS/AWSS stations providing
service levels A or B also report RVR. The specific type
of equipment found at a given facility is listed in the CS.
[Figure 1-12]
The use of the aforementioned visibility reports and
weather services are not limited for Part 91 operators.
Part 121 and 135 operators are bound by their individual
OpSpecs documents and are required to use weather
reports that come from the NWS or other approved
sources. While every operator’s specifications are
individually tailored, most operators are required to use
ATIS, RVR reports, and selected reports from automated
weather stations. All reports coming from an AWOS-3
station are usable for Part 121 and Part 135 operators. Each
type of automated station has different levels of approval
as outlined in individual OpSpecs. Ceiling and visibility
reports given by the tower with the departure information
are always considered official weather, and RVR reports are
typically the controlling visibility reference.
Automatic Terminal Information Service (ATIS)
ATIS is another valuable tool for gaining weather
information. ATIS is available at most airports that have an
operating control tower, which means the reports on the
ATIS frequency are only available during the regular hours
of tower operation. At some airports that operate part-time
towers, ASOS/AWSS information is broadcast over the
ATIS frequency when the tower is closed. This service is
available only at those airports that have both an ASOS/
AWSS on the field and an ATIS-ASOS/AWSS interface switch
installed in the tower.
Each ATIS report includes crucial information about
runways and instrument approaches in use, specific
outages, and current weather conditions including
visibility. Visibility is reported in statute miles and may
be omitted if the visibility is greater than five miles. ATIS
weather information comes from a variety of sources
depending on the particular airport and the equipment
installed there. The reported weather may come from a
manual weather observer, weather instruments located
in the tower, or from automated weather stations. This
information, no matter the origin, must be from NWS
approved weather sources for it to be used in the ATIS
report.
Digital Automatic Terminal Information Service
(D-ATIS)
The digital ATIS (D-ATIS) is an alternative method of
receiving ATIS reports. The service provides text messages
to aircraft, airlines, and other users outside the standard
reception range of conventional ATIS via landline and data
link communications to the flight deck. Aircraft equipped
with data link services are capable of receiving ATIS
information over their Aircraft Communications Addressing
and Reporting System (ACARS) unit. This allows the pilots to
read and print out the ATIS report inside the aircraft, thereby
increasing report accuracy and decreasing pilot workload.
Also, the service provides a computer-synthesized voice
message that can be transmitted to all aircraft within
range of existing transmitters. The Terminal Data Link
System (TDLS) D-ATIS application uses weather inputs
from local automated weather sources or manually entered
meteorological data together with preprogrammed menus
to provide standard information to users. Airports with
D-ATIS capability are listed in the CS.
SW-1, 23 SEP 2010 to 21 OCT 2010
SW-1, 23 SEP 2010 to 21 OCT 2010
INSTRUMENT APPROACH PROCEDURE CHARTS
IFR ALTERNATE AIRPORT MINIMUMS
Standard alternate minimums for non precision approaches are 800-2 (NDB, VOR, LOC, TACAN, LDA,
VORTAC, VOR/DME, ASR or WAAS LNAV); for precision approaches 600-2 (ILS or PAR). Airports within
this geographical area that require alternate minimums other than standard or alternate minimums with
restrictions are listed below. NA - means alternate minimums are not authorized due to unmonitored facility
or absence of weather reporting service. Civil pilots see FAR 91. IFR Alternate Airport Minimums: Ceiling
and Visibility Minimums not applicable to USA/USN/USAF. Pilots must review the IFR Alternate Airport
Minimums Notes for alternate airfield suitability.
NAME ALTERNATE MINIMUMS NAME ALTERNATE MINIMUMS
AKRON, CO
COLORADO
PLAINS RGNL ................. RNAV (GPS) Rwy 11
NA when local weather not available.
ALAMOSA, CO
SAN LUIS VALLEY RGNL/
BERGMAN FIELD .............. RNAV (GPS) Rwy 2
RNAV (GPS) Rwy 20
NA when local weather not available.
ALBUQUERQUE, NM
ALBUQUERQUE INTL
SUNPORT ..................... VOR or TACAN Rwy 8
Categories A,B, 900-2; Category C, 900-2 ;
Category D, 900-2 ; Category E, 900-3.
CLAYTON, NM
CLAYTON MUNI AIRPARK ............ NDB Rwy 2
NDB Rwy 20
RNAV (GPS) Rwy 2
RNAV (GPS) Rwy 20
NA when local weather not available.
Categories A, B, 900-2; Category C, 900-2 ,
Category D, 900-2 .
Category D, 800-2 .
COLORADO SPRINGS, CO
CITY OF COLORADO SPRINGS
MUNI .............................. ILS or LOC Rwy 17L
ILS or LOC Rwy 35L
ILS or LOC Rwy 35R
RNAV (GPS) Y Rwy 17L
RNAV (GPS) Y Rwy 17R 4
RNAV (RNP) Z Rwy 17R5
Categories A, B, 900-2; Category C, 900-2 ;
Category D, 900-2 .
ILS, Category D, 700-2.
NA when local weather not available.
4Categories A, B, 1100-2; Categories C, D,
1100-3.
5Categories A, B, C, D, 800-2 .
CORTEZ, CO
CORTEZ MUNI ............ RNAV (GPS) Y Rwy 21
RNAV (GPS) Z Rwy 21
VOR Rwy 21
Category D, 900-3.
Categories A, B, 1300-2; Categories C, D,
1300-3.
CRAIG, CO
CRAIG-MOFFAT .................... VOR/DME Rwy 7
VOR Rwy 25
23 SEP 2010 to 21 OCT 2010
23 SEP 2010 to 21 OCT 2010
SAMPLE NOT FOR ACTUAL USE
NOT FOR NAVIGATION
City and state location
Airport name and applicable approach
Other-than-standard IFR alternate minimums
Other-than-standard IFR alternate minimums are published.
Figure 1-13. Examples of IFR alternate minimums.
It is important to remember that ATIS information is
updated hourly and anytime a significant change in the
weather occurs. As a result, the information is not the most
current report available. Prior to departing the airport, you
need to get the latest weather information from the tower.
ASOS/AWSS and AWOS also provide a source of current
weather, but their information should not be substituted
for weather reports from the tower.
IFR Alternate Requirements
On Aeronautical Information Services charts, standard
alternate minimums are not published. If the airport has
other than standard alternate minimums, they are listed
in the front of the approach chart booklet. The presence
of a triangle with an A on the approach chart indicates
the listing of alternate minimums should be consulted.
Airports that do not qualify for use as an alternate airport
are designated with an A N/A. [Figure 1-13]
The requirement for an alternate depends on the aircraft
category, equipment installed, approach navigational aid
(NAVAID), and forecast weather. For example, airports with
only a global positioning system (GPS) approach procedure
cannot be used as an alternate by TSO-C129 or C196 users
unless certain requirements are met (see AIM) even
though the "N/A" has been removed from the approach
chart. For select area navigation (RNAV) GPS and GPS
approach procedures, the "N/A" is being removed so they
may be used as an alternate by aircraft equipped with an
approach-approved Wide Area Augmentation System
(WAAS) receiver complaying with (TSO-C145 or C146)
or TSO-C129 or C196 meeitng certain requirements (see
AIM). Because GPS is not authorized as a substitute means
of navigation guidance when conducting a conventional
approach at an alternate airport, if the approach procedure
requires either distance measuring equipment (DME) or
automatic direction finder (ADF), the aircraft must be
equipped with the appropriate DME or ADF avionics in
order to use the approach as an alternate.
For aircraft other than helicopters, 14 CFR Part 91
requirements, an alternate airport must be listed on IFR
flight plans if the forecast weather at the destination
airport, for at least one hour before and for one hour after
the estimated time of arrival (ETA), the ceiling is less than
2,000 feet above the airport elevation, and the visibility
is less than 3 SM. One way to remember the rules for
determining the necessity of filing an alternate is the “1, 2,
3 Rule. ” For helicopters, similar alternate filing requirements
in 14 CFR Part 91 apply. An alternate must be listed on an
IFR flight plan if at the ETA and for one hour after the ETA,
the ceiling is at least 1,000 feet above the airport elevation,
or at least 400 feet above the lowest applicable approach
minima, whichever is higher, and the visibility is at least
2 SM.
Not all airports can be used as alternate airports. An airport
may not be qualified for alternate use if the airport NAVAID
is unmonitored, or if it does not have weather reporting
capabilities. For an airport to be used as an alternate,
the forecast weather at that airport must meet certain
qualifications at the ETA. For aircraft other than helicopters,
standard alternate minimums for a precision approach are
a 600-foot ceiling and a 2 SM visibility. For a non-precision
approach, the minimums are an 800-foot ceiling and a 2 SM
visibility. Standard alternate minimums apply unless higher
alternate minimums are listed for an airport. For helicopters,
alternate weather minimums are a ceiling of 200 feet above
the minimum for the approach to be flown, and visibility
at least 1 SM but never less than the minimum visibility for
the approach to be flown.
Alternate Minimums for Commercial Operators
IFR alternate minimums for Part 121 and Part 135 operators
are very specific and have more stringent requirements
than Part 91 operators.
Part 121 operators are required by their OpSpecs and 14
CFR Part 121, § 121.617 and 121.625 to have a takeoff
alternate airport for their departure airport in addition
to their airport of intended landing if the weather at the
departure airport is below the landing minimums in the
certificate holder’s OpSpecs for that airport. The alternate
must be within two hours flying time for an aircraft with
three or more engines with an engine out in normal cruise
in still air. For two engine aircraft, the alternate must be
within one hour. The airport of intended landing may be
used in lieu of an alternate provided that it meets all the
requirements. Domestic Part 121 operators must also file
for alternate airports when the weather at their destination
airport, from one hour before to one hour after their ETA, is
forecast to be below a 2,000-foot ceiling and/or less than
three miles visibility.
For alternate airports with at least one operational
navigational facility that provides a straight-in non-
precision approach, a straight-in precision approach, or a
circling maneuver from an instrument approach procedure
determine the ceiling and visibility by:
• Adding 400 feet to the authorized CAT I height above
airport (HAA)/height above touchdown elevation
(HAT) for ceiling.
• Adding one mile to the authorized CAT I visibility
for visibility minimums.
This is one example of the criteria required for Part 121
operators when calculating minimums. Part 135 operators
are also subject to their own specific rules regarding the
selection and use of alternate minimums as outlined in their
OpSpecs and 14 CFR Part 135, § 135.219 through 135.225,
which are similar to those used by Part 121 operators with
additional considerations.
Commercial operators typically use dispatchers to plan
flights, including selecting and filing alternate airports.
The dispatcher considers aircraft performance, aircraft
equipment and its condition, and route of flight when
choosing alternates. In the event changes need to be
made to the flight plan en route due to deteriorating
weather, the dispatcher maintains contact with the flight
crew and reroutes their flight as necessary. Therefore, it is
the pilot’s responsibility to execute the flight as planned
by the dispatcher. To aid in the planning of alternates,
dispatchers have a list of airports that are approved as
alternates so they can quickly determine which airports
should be used for a particular flight. Dispatchers also
use flight planning software that plans routes including
alternates for the flight. This type of software is tailored
for individual operators and includes their normal flight
paths and approved airports. Flight planning software and
services are provided through private sources.
Though the pilot is the final authority for the flight
and ultimately has full responsibility, the dispatcher is
responsible for creating flight plans that are accurate and
comply with the CFRs. Alternate minimum criteria are only
used as planning tools to ensure the pilot in command and
dispatcher are thinking ahead to the approach phase of
flight. In the event the flight would actually need to divert
to an alternate, the published approach minimums or
lower-than-standard minimums must be used as addressed
in OpSpecs documents.
' '
1 NM 2 NM
10 NM
200 feet
400 feet
Positive course guidance must be acquired
within 10 NM for straight departures and
within 5 NM for departures requiring turns.
Required climb gradient of 200 ft/NM
Previous TERPS Departure Procedures
Obstacle clearance surface (OCS)
35 feet35 feet
152 feet152 feet
304 feet304 feet
96 feet96 feet
Figure 1-14. Previous TERPS departure procedures.
Beyond the diverse obstacle assessment
area (25/46 NM) there might be significantly
higher obstacles.
Aircraft reaches en route obstacle
clearance of 1,000' (nonmountainous
areas) or 2,000' (in mountainous areas).
TERPS Design CG of 200
ft/NM
40:1 OIS at 152
ft/NM
4NM
25/46 NM
Figure 1-15. Diverse Departure Obstacle Assessment to 25/46 NM.
1 NM 2 NM
200 feet
400 feet
First
Significant
Obstacle
Clearway
TORA
TODA
TORA
ASDA
Stopway
75 Meters
(247 Feet)
Positive Course Guidance (PCG)
A continuous display of navigational data
that enables an aircraft to be flown along a
specific course line (e.g., radar vector,
RNAV, ground-based NAVAID). PCG must
be acquired within 10 NM for straight
departures and within 5 NM for departures
requiring turns.
Departure End of Runway (DER)
The end of runway available for the ground run of an aircraft
departure. The end of the runway that is opposite the landing
threshold, sometimes referred to as the stop end of the runway.
Takeoff Runway Available (TORA)
The length of runway declared available and suitable
for the ground run of an airplane takeoff.
Takeoff Distance Available (TODA)
The length of the takeoff runway available plus
the length of the clearway, if provided.
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.
Initial Climb Area (ICA)
The ICA is the segment of the departure procedure that
starts at the DER and proceeds along the runway
centerline extended to allow the aircraft sufficient distance
to reach an altitude of 400 feet above DER elevation and
to allow the establishment of positive course guidance by
all navigation systems. A typical straight departure ICA
extends 2-5 NM from the DER along the runway centerline
extended. It is 500 feet wide each side of the runway
centerline at DER, then spreads out at 15°.
Start End of Runway (SER)
The beginning of the takeoff runway available.
Approach End of Runway (AER)
The first portion of the runway available for landing.
If the runway threshold is displaced, the displaced
threshold latitude/longitude is the AER.
Landing Distance Available (LDA)
The length of runway that is declared available and
suitable for the ground run of an airplane landing.
TERPS Departure Procedures and
runway distance available terms.
48 ' 48 '
35 feet35 feet 152 feet152 feet
304 feet304 feet
96 feet96 feetRequired climb
gradient of 200 ft/NM
Obstacle clearance surface (OCS)
Slope of 152 ft/NM or 40:1
Runway
Centerline Extended
Minimum assumed “at or above” intended aircraft climb path
Figure 1-16. New TERPS departure procedures.
Departure Procedures
Instrument departure procedures are preplanned IFR
procedures that provide obstruction clearance from
the terminal area to the appropriate en route structure.
Primarily, these procedures are designed to provide obstacle
protection for departing aircraft. There are two types of
Departure Procedures (DPs):
• Obstacle Departure Procedures (ODPs) and
• Standard Instrument Departures (SIDs).
When an instrument approach is initially developed for an
airport, the need for an ODP is assessed. If an aircraft may
turn in any direction from a runway within the limits of the
assessment area and remain clear of obstacles that runway
passes what is called a diverse departure assessment, and
no ODP is published. A diverse departure assessment
ensures that a prescribed, expanding amount of required
obstacle clearance (ROC) is achieved during the climb-out
until the aircraft can obtain a minimum 1,000 feet ROC in
non-mountainous areas or a minimum 2,000 feet ROC in
mountainous areas. Unless specified otherwise, required
obstacle clearance for all departures, including diverse, is
based on the pilot crossing the departure end of the runway
(DER) at least 35 feet above the DER elevation, climbing to
400 feet above the DER elevation before making the initial
turn, and maintaining a minimum climb gradient of 200 ft/
NM, unless required to level off by a crossing restriction,
until the minimum IFR altitude is reached. Following ODP
assessment, a SID may still be established for the purposes
of ATC flow management, system enhancement, or noise
abatement.
Design Criteria
The design of a departure procedure is based on FAA Order
8260.3, United States Standard for Terminal Instrument
Procedures (TERPS), which is a living document that is
updated frequently. Departure design criterion begins
with the assumption of an initial climb of 200 ft/NM after
crossing the DER at a height of at least 35 feet. [Figure 1-14]
The aircraft climb path assumption provides a minimum of
35 feet of additional obstacle clearance above the required
obstacle clearance (ROC), from the DER outward, to absorb
variations ranging from the distance of the static source to
the landing gear, to differences in establishing the minimum
200 ft/NM climb gradient, etc. The ROC is the planned