Figure 3-7. Jet descent task.
Pressure Altitude
(1,000 feet)
Note: Subtract 30 lb of fuel and 36 seconds for each
1,000 feet that the destination airport is above sea level
Time
(minutes)
Fuel
(pounds)
Distance
(NM)
NOTE:
.80/280
SAMPLE NOT FOR ACTUAL USE
below 10,000 feet MSL is not included on the chart, since its
effect is minimal. Also, the effect of temperature or weight
variation is negligible and is therefore omitted.
Due to the increased flight deck workload, pilots should
get as much done ahead of time as possible. As with the
climb and cruise phases of flight, aircrews should consult
the proper performance charts to compute their fuel
requirements, as well as the time and distance needed for
their descent.
During the cruise and descent phases of flight, pilots
need to monitor and manage the aircraft according to
the appropriate manufacturer’s recommendations. Flight
manuals and operating handbooks contain cruise and
descent checklists, performance charts for specific cruise
configurations, and descent charts that provide information
regarding the fuel, time, and distance required to descend.
Aircrews should review this information prior to the
departure of every flight so they have an understanding of
how the aircraft is supposed to perform at cruise and during
descent. A stabilized descent constitutes a preplanned
maneuver in which the power is properly set, and minimum
control input is required to maintain the appropriate
descent path. Excessive corrections or control inputs
indicate the descent was improperly planned. Plan the IFR
descent from cruising altitude so that the aircraft arrives at
the approach gate altitude or initial approach fix altitude
prior to beginning the instrument approach. For example,
suppose you are asked to descend from 11,000 feet to
meet a crossing restriction at 3,000 feet. [Figure 3-8] Since
there is a 200 knot speed restriction while approaching
the destination airport, you choose a descent speed of
190 knots and a descent rate of 1,000 fpm. Assuming a 10
knot headwind component, groundspeed in the descent
is 180 knots.
Descending From the En Route Altitude
Making the transition from cruise flight to the beginning
of an instrument approach procedure sometimes requires
arriving at a given waypoint at an assigned altitude. When
this requirement is prescribed by a published arrival
procedure or issued by ATC, it is called a crossing restriction.
Even when ATC allows a descent at the pilot’s discretion,
Wind
Top-of-descent point
Bottom-of-descent point
ECA VOR
Cruising altitude ft0
Assigned altitude ft0
Cruising speed knots0
Descent speed and rate
knots @ 1,000 fpm0
Figure 3-8. The descent planning task.
aircrews need to choose a waypoint and altitude for
positioning convenient to start the approach. In either case,
descending from a cruising altitude to a given waypoint or
altitude requires both planning and precise flying.
ATC may ask the pilot to descend to and maintain a
specific altitude. Generally, this clearance is for en route
traffic separation purposes, and pilots need to respond to
it promptly. Descend at the optimum rate for the aircraft
being flown until 1,000 feet above the assigned altitude,
then descend at a rate between 500 and 1,500 fpm to the
assigned altitude. If at any time, other than when slowing
to 250 KIAS at 10,000 feet MSL, the pilot cannot descend
at a rate of at least 500 fpm, advise ATC.
The second type of clearance allows the pilot to descend
“ … at pilot’s discretion. ” When ATC issues a clearance to
descend at pilot’s discretion, pilots may begin the descent
whenever they choose and at any rate of their choosing.
Pilots are also authorized to level off, temporarily, at any
intermediate altitude during the descent. However, once
the aircraft leaves an altitude, it may not return to that
altitude.
A descent clearance may also include a segment where the
descent is at the pilots’ discretion—such as “cross the Joliet
VOR at or above 12,000, descend and maintain 5,000. ”This
clearance authorizes pilots to descend from their current
altitude whenever they choose, as long as they cross the
Joliet VOR at or above 12,000 feet MSL. After that, they are
expected to descend at a normal rate until they reach the
assigned altitude of 5,000 feet MSL.
Clearances to descend at pilots’ discretion are not just an
option for ATC. Pilots may also request this type of clearance
so that they can operate more efficiently. For example, if
a pilot was en route above an overcast layer, he or she
might ask for a descent at his or her discretion to allow the
aircraft to remain above the clouds for as long as possible.
This might be particularly important if the atmosphere
is conducive to icing and the aircraft’s icing protection
is limited. The pilot’s request permits the aircraft to stay
at its cruising altitude longer to conserve fuel or to avoid
prolonged IFR flight in icing conditions. This type of descent
can also help to minimize the time spent in turbulence by
allowing pilots to level off at an altitude where the air is
smoother.
Controlled Flight Into Terrain (CFIT)
Inappropriate descent planning and execution during
arrivals has been a contributing factor to many fatal
aircraft accidents. Since the beginning of commercial jet
operations, more than 9,000 people have died worldwide
because of controlled flight into terrain (CFIT). CFIT is
described as an event in which a normally functioning
aircraft is inadvertently flown into the ground, water, or an
obstacle. Of all CFIT accidents, 7.2 percent occurred during
the descent phase of flight.
The basic causes of CFIT accidents involve poor flight crew
situational awareness, or SA. One definition of SA is an
accurate perception by pilots of the factors and conditions
currently affecting the safe operation of the aircraft and the
crew. The causes of CFIT are the flight crews’ lack of vertical
position awareness or their lack of horizontal position
awareness in relation to the ground, water, or an obstacle.
More than two-thirds of all CFIT accidents are the result
of an altitude error or lack of vertical SA. CFIT accidents
most often occur during reduced visibility associated with
instrument meteorological conditions (IMC), darkness, or
a combination of both.
The inability of controllers and pilots to properly
communicate has been a factor in many CFIT accidents.
Heavy workloads can lead to hurried communication and
the use of abbreviated or non-standard phraseology. The
importance of good communication during the arrival
phase of flight was made evident in a report by an air traffic
controller and the flight crew of an MD-80.
The controller reported that he was scanning his radarscope
for traffic and noticed that the MD-80 was descending
through 6,400 feet. He immediately instructed a climb
to at least 6,500 feet. The pilot returned to 6,500 feet, but
responded to ATC that he had been cleared to 5,000 feet.
When he had read back 5,000 feet to the controller, he
received no correction from the controller. After almost
simultaneous ground proximity warning system (GPWS)
and controller warnings, the pilot climbed and avoided
the terrain. The recording of the radio transmissions
confirmed that the aircraft was cleared to 7,000 feet and
the pilot mistakenly read back 5,000 feet then attempted
to descend to 5,000 feet. The pilot stated in the report: “I
don’t know how much clearance from the mountains we
had, but it certainly makes clear the importance of good
communications between the controller and pilot. ”
ATC is not always responsible for safe terrain clearance for
the aircraft under its jurisdiction. Many times ATC issue en
route clearances for pilots to proceed off airway direct to
a point. Pilots who accept this type of clearance also are
accepting the shared responsibility for maintaining safe
terrain clearance. Know the height of the highest terrain
and obstacles in the operating area and your position in
relation to the surrounding high terrain.
The following are excerpts from CFIT accidents related
“I need to check my altitude requirement.”
“....cleared present position direct.....”
Figure 3-9. Altitude management when cleared direct.
to descending on arrival: “ …delayed the initiation of the
descent… ”; “Aircraft prematurely descended too early… ”;
“ …late getting down… ”; “During a descent…incorrectly
cleared down… ”; “ …aircraft prematurely let down… ”;
“ …lost situational awareness… ”; “Premature descent
clearance… ”; “Prematurely descended… ”; “Premature
descent clearance while on vector… ”; “During initial
descent… ” [Figure 3-9]
Practicing good communication skills is not limited to just
pilots and controllers. In its findings from a 1974 air carrier
accident, the National Transportation Safety Board (NTSB)
wrote, “ …the extraneous conversation conducted by the
flight crew during the descent was symptomatic of a lax
atmosphere in the flight deck that continued throughout
the approach. ” The NTSB listed the probable cause as “ …
the flight crew’s lack of altitude awareness at critical points
during the approach due to poor flight deck discipline in
that the crew did not follow prescribed procedures. ”
In 1981, the FAA issued 14 CFR Part 121, § 121.542 and
Part 135, § 135.100, Flight Crewmember Duties, commonly
referred to as “sterile flight deck rules. ”The provisions in this
rule can help pilots, operating under any regulations, to
avoid altitude and course deviations during arrival. In part,
it states: (a) No certificate holder should require, nor may
any flight crewmember perform, any duties during a critical
phase of flight except those duties required for the safe
operation of the aircraft. Duties such as company required
calls made for such purposes as ordering galley supplies
and confirming passenger connections, announcements
made to passengers promoting the air carrier or pointing
out sights of interest, and filling out company payroll and
related records are not required for the safe operation of
the aircraft. (b) No flight crewmember may engage in, nor
may any pilot in command permit, any activity during
a critical phase of flight that could distract any flight
crewmember from the performance of his or her duties or
which could interfere in any way with the proper conduct
of those duties. Activities such as eating meals, engaging
in nonessential conversations within the flight deck and
nonessential communications between the cabin and
flight deck crews, and reading publications not related to
the proper conduct of the flight are not required for the
safe operation of the aircraft. (c) Critical phases of flight
include all ground operations involving taxi, takeoff and
landing, and all other flight operations conducted below
10,000 feet, except cruise flight.
Standard Terminal Arrival Routes
(STARs)
A STAR is an ATC-coded IFR route established for application
to arriving IFR aircraft destined for certain airports. A STAR
provides a critical form of communication between pilots
and ATC. Once a flight crew has accepted a clearance for a
STAR, they have communicated with the controller what
route, and in some cases what altitude and airspeed, they
fly during the arrival, depending on the type of clearance.
The STAR provides a common method for leaving the en
route structure and navigating to your destination. It is a
preplanned instrument flight rule ATC arrival procedure
published for pilot use in graphic and textual form that
simplifies clearance delivery procedures.
The principal difference between standard instrument
departure (SID) or departure procedures (DPs) and STARs
is that the DPs start at the airport pavement and connect
to the en route structure. STARs on the other hand, start
at the en route structure but do not make it down to the
pavement. This is primarily because STARs serve multiple
runways and sometimes multiple airports.
Figure 3-10. Arrival charts.
STARs greatly help to facilitate the transition between the
en route and approach phases of flight. The STAR will end
at a fix or NAVAID, designated by ATC, which allows for
radar vectors and/or to connect to an instrument approach
procedure. The objective when connecting a STAR to an
instrument approach procedure is to ensure a seamless
lateral and vertical transition. The STAR and approach
procedure should connect to one another in such a way as
to maintain the overall descent and deceleration profiles.
This often results in a seamless transition between the en
route, arrival, and approach phases of flight, and serves as
a preferred route into high volume terminal areas. [Figure
3-10]
STARs provide a transition from the en route structure to an
approach gate, outer fix, instrument approach fix, or arrival
waypoint in the terminal area, and they usually terminate
with an instrument or visual approach procedure. STARs
are included at the front of each Terminal Procedures
Publication (TPP) regional booklet.
For STARs based on conventional NAVAIDs, the procedure
design and obstacle clearance criteria are essentially the
same as that for en route criteria, covered in Chapter 2,
En Route Operations. STAR procedures typically include
a descent gradient of about 318 ft/NM, or about three
degrees. The descent gradient on a STAR will have to vary
to meet altitude restrictions, if any, along the particular
route. Altitude restrictions are frequently necessary for
airspace and air traffic restrictions. The design guidance for
a new or revised STAR is in FAA Order 8260.3, published in
March 2016. Some published STARs were designed under
the previous guidance in FAA Order JO 7110.9. The new
guidance requires a more shallow descent gradient for the
last part of the STAR. In addition to descent gradients, STARs
allow for deceleration segments at any waypoint that has
a speed restriction. As a general guideline, deceleration
considerations typically add 1 NM of distance for each 10
knots of speed reduction required.
RNAV STARs or STAR Transitions
STARs designated RNAV serve the same purpose as
conventional STARs, but are only used by aircraft equipped
with FMS or GPS. An RNAV STAR or STAR transition typically
includes flyby waypoints, with fly over waypoints used
only when operationally required. These waypoints may
be assigned crossing altitudes and speeds to optimize
the descent and deceleration profiles. RNAV STARs often
are designed, coordinated, and approved by a joint effort
between air carriers, commercial operators, and the ATC
facilities that have jurisdiction for the affected airspace.
RNAV STAR procedure design, such as minimum leg
length, maximum turn angles, obstacle assessment criteria,
including widths of the primary and secondary areas, use
similar design criteria as other RNAV procedures. Likewise,
RNAV STAR procedures are designated as either RNAV 1
or RNAV 2, based on the aircraft navigation equipment
required, flight crew procedures, and the process and
criteria used to develop the STAR. The RNAV 1 or RNAV
2 designation appears in the notes on the chart. RNAV 1
STARs have higher equipment requirements and, often,
tighter required navigation performance (RNP) tolerances
than RNAV 2. For RNAV 1 STARS, pilots are required to use
a course deviation indicator (CDI)/flight director, and/or
autopilot in LNAV mode while operating on RNAV courses.
(These requirements are detailed in Chapter 1 of this book,
under RNAV Departures.) RNAV 1 STARs are generally
designated for high-traffic areas. Controllers may clear a
pilot to use an RNAV STAR in various ways.
If the pilots clearance simply states, “cleared HADLY ONE
arrival, ” the pilot is to use the arrival for lateral routing only.
• A clearance such as “cleared HADLY ONE arrival,
descend and maintain flight level two four zero, ”
clears the pilot to descend only to the assigned
altitude, and then should maintain that altitude until
cleared for further descent.
• If the pilot is cleared using the phrase “descend via, ”
the controller expects the pilot to use the equipment
for both lateral guidance and altitude restrictions, as
published on the chart.
• The controller may also clear the pilot to use the
arrival with specific exceptions—for example,
“Descend via the HARIS ONE arrival, except cross
BRUNO at one three thousand then maintain one
zero thousand. ” In this case, the pilot should track the
arrival both laterally and vertically, descending so as
to comply with all altitude and airspeed restrictions
until reaching BRUNO, and then maintain 10,000 feet
until cleared by ATC to continue to descend.
• Pilots might also be given direct routing to intercept
a STAR and then use it for both lateral guidance and
altitude restrictions. For example, “Proceed direct
MAHEM, descend via the MAHEM TWO arrival. ”
Interpreting the STAR
STARs use much of the same symbology as departure
and approach charts. In fact, a STAR may at first appear
identical to a similar graphic DP , except the direction of
flight is reversed and the procedure ends at a fix. The STAR
arrival route, also called the basic STAR procedure or the
common route or common point, begins at the common
Figure 3-11. STAR interpretation.
NAVAID, intersection, or fix where all the various (en route)
transitions to the arrival come together. A STAR en route
transition is a published segment used to connect one or
more en route airways, jet routes, or RNAV routes to the
basic STAR procedure. It is one of several routes that bring
traffic from different directions into one STAR. This way,
arrivals from several directions can be accommodated on
the same chart, and traffic flow is routed appropriately
within the congested airspace.
To illustrate how STARs can be used to simplify a complex
clearance and reduce frequency congestion, consider
the following arrival clearance issued to a pilot flying to
Seattle, Washington, depicted in Figure 3-11: “Cessna 32G,
cleared to the Seattle/Tacoma International Airport as filed.
Maintain 12,000. At the Ephrata VOR, intercept the 221°
radial to CHINS Intersection. Intercept the 284° radial of the
Yakima VOR to RADDY Intersection. Cross RADDY at 10,000.
Figure 3-12. Reducing pilot/controlling workload.