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.
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
Each pilot who deviates from an ATC
clearance in response to a Traffic Alert and Collision
Avoidance System resolution advisory shall notify ATC
of that deviation as soon as possible.
Pilot/Controller Glossary Term- Traffic Alert and
Collision Avoidance System.
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.
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
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. 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.
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, DP's have been
AIM, Abbreviated IFR Departure Clearance (Cleared...as
Filed) Procedures, Paragraph
AIM, Instrument Departures, Paragraph
c. Route of Flight.
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.
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.
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.
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.
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.
Pilot/Controller Glossary Term- Cruise.
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
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 shall
always issue complete holding instructions when
pilots request them.
Only those holding patterns depicted on U.S.
government or commercially produced charts which
meet FAA requirements should be used.
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.
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
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
Pilots should report to ATC the time
and altitude/flight level at which the aircraft
reaches the clearance limit and report leaving the
In the event of two-way communications failure,
pilots are required to comply with 14 CFR Section
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.
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
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.
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
Special VFR Clearances
An ATC 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:
At least 1 statute mile flight
visibility for operations within Class B, Class C,
Class D, and Class E surface areas.
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.
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.
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.
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.
The pilot is responsible for obstacle or terrain
14 CFR Section 91.119, Minimum safe altitudes:
Special VFR clearances are effective
within Class B, Class C, Class D, and Class E surface
areas only. ATC 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.
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
ATC provides separation between Special
VFR flights and between these flights and other IFR
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.
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.
Pilot/Controller Glossary Term- One-minute Weather.
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.
Pilots of airborne aircraft should read
back those parts of ATC clearances and
instructions containing altitude assignments or
vectors as a means of mutual verification. The
readback 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.
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 identification in
all readbacks and acknowledgements becomes more
important as frequency congestion increases and when
aircraft with similar call signs are on the same
"Climbing to Flight Level three three zero, United
Twelve" or "November Five Charlie Tango, roger,
cleared to land."
Read back altitudes, altitude
restrictions, and vectors in the same sequence as
they are given in the clearance or instruction.
Altitudes contained in charted
procedures, such as DP's, instrument approaches,
etc., should not be read back unless they are
specifically stated by the controller.
It is the responsibility of the pilot
to accept or refuse the clearance issued.
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.)
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 shall 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.
A pilot on an IFR flight plan,
operating in VFR conditions, may request to
climb/descend in VFR conditions.
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.
When operating in VFR conditions with
an ATC authorization to "maintain VFR-on-top/maintain
VFR conditions" pilots on IFR flight plans must:
Fly at the appropriate VFR altitude
as prescribed in 14 CFR Section 91.159.
Comply with the VFR visibility and
distance from cloud criteria in 14 CFR Section
91.155 (Basic VFR Weather Minimums).
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
Pilots should advise ATC prior to any altitude
change to insure the exchange of accurate traffic
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.
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/TRSA's shall be
separated as required by FAA Order
7110.65, Air Traffic Control.
When operating in VFR weather conditions, it is the
pilot's responsibility to be vigilant so as to
see-and-avoid other aircraft.
ATC will not authorize VFR or VFR-on-top
operations in Class A airspace.
AIM, Class A Airspace, Paragraph
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/MVA/OROCA,
pilots are responsible for their own terrain/obstruction
clearance until reaching the MEA/MIA/MVA/OROCA. If
pilots are unable to maintain terrain/obstruction
clearance, the controller should be advised and pilots
should state their intentions.
OROCA is an off-route altitude which provides
obstruction clearance with a 1,000 foot buffer in
nonmountainous terrain areas and a 2,000 foot buffer in
designated mountainous areas within the U.S. This
altitude may not provide signal coverage from
ground-based navigational aids, air traffic control
radar, or communications coverage.
Adherence to Clearance
When air traffic clearance has been
obtained under either visual or instrument flight
rules, the pilot-in-command of the aircraft shall 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.
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.
The term "AT PILOT'S DISCRETION"
included in the altitude information of an ATC
clearance means that ATC 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
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 B, Class C, or Class D surface area), when
required for speed reduction.
14 CFR Section 91.117.
Leveling off at 10,000 feet MSL on descent or 2,500
feet above airport elevation (prior to entering a
Class B, 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
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 portion of the flight to which the
crossing altitude restriction applies, and the pilot
is expected to comply with the crossing altitude as a
provision of the clearance. Any other clearance in
which pilot execution is optional will so state "AT
1. "United Four
Seventeen, descend and maintain six thousand."
1. The pilot is
expected to commence descent upon receipt of the
clearance and to descend at the suggested rates until
reaching the assigned altitude of 6,000 feet.
2. "United Four
Seventeen, descend at pilot's discretion, maintain six
2. The pilot is
authorized to conduct descent within the context of
the term at pilot's discretion as described above.
3. "United Four
Seventeen, cross Lakeview V-O-R at or above Flight
Level two zero zero, descend and maintain six
3. The pilot is
authorized to conduct descent at pilot's discretion
until reaching Lakeview VOR and must comply with the
clearance provision to cross the Lakeview VOR at or
above FL 200. After passing Lakeview VOR, the pilot is
expected to descend at the suggested rates until
reaching the assigned altitude of 6,000 feet.
4. "United Four
Seventeen, cross Lakeview V-O-R at six thousand,
maintain six thousand."
4. The pilot is
authorized to conduct descent at pilot's discretion,
however, must comply with the clearance provision to
cross the Lakeview VOR at 6,000 feet.
5. "United Four
Seventeen, descend now to Flight Level two seven zero,
cross Lakeview V-O-R at or below one zero thousand,
descend and maintain six thousand."
5. The pilot is
expected to promptly execute and complete descent to
FL 270 upon receipt of the clearance. After reaching
FL 270 the pilot is authorized to descend "at pilot's
discretion" until reaching Lakeview VOR. The pilot
must comply with the clearance provision to cross
Lakeview VOR at or below 10,000 feet. After Lakeview
VOR the pilot is expected to descend at the suggested
rates until reaching 6,000 feet.
6. "United Three
Ten, descend now and maintain Flight Level two four
zero, pilot's discretion after reaching Flight Level
two eight zero."
6. The pilot is
expected to commence descent upon receipt of the
clearance and to descend at the suggested rates until
reaching FL 280. At that point, the pilot is
authorized to continue descent to FL 240 within the
context of the term "at pilot's discretion" as
In case emergency authority is used to
deviate from provisions of an ATC clearance, the
pilot-in-command shall notify ATC as soon as possible
and obtain an amended clearance. In an emergency
situation which does not result in a deviation from
the rules prescribed in 14 CFR Part 91 but which
requires ATC to give priority to an aircraft, the
pilot of such aircraft shall, when requested by ATC,
make a report within 48 hours of such emergency
situation to the manager of that ATC facility.
The guiding principle is that the last
ATC clearance has precedence over the previous ATC
clearance. When the route or altitude in a previously
issued clearance is amended, the controller will
restate applicable altitude restrictions. If altitude
to maintain is changed or restated, whether prior to
departure or while airborne, and previously issued
altitude restrictions are omitted, those altitude
restrictions are canceled, including departure
procedures and STAR altitude restrictions.
1. A departure
flight receives a clearance to destination airport to
maintain FL 290. The clearance incorporates a DP which
has certain altitude crossing restrictions. Shortly
after takeoff, the flight receives a new clearance
changing the maintaining FL from 290 to 250. If the
altitude restrictions are still applicable, the
controller restates them.
2. A departing aircraft is cleared to cross
Fluky Intersection at or above 3,000 feet, Gordonville
VOR at or above 12,000 feet, maintain FL 200. Shortly
after departure, the altitude to be maintained is
changed to FL 240. If the altitude restrictions are
still applicable, the controller issues an amended
clearance as follows: "cross Fluky Intersection at or
above three thousand, cross Gordonville V-O-R at or
above one two thousand, maintain Flight Level two four
3. An arriving aircraft is cleared to
the destination airport via V45 Delta VOR direct; the
aircraft is cleared to cross Delta VOR at 10,000 feet,
and then to maintain 6,000 feet. Prior to Delta VOR,
the controller issues an amended clearance as follows:
"turn right heading one eight zero for vector to
runway three six I-L-S approach, maintain six
Because the altitude restriction "cross Delta V-O-R at
10,000 feet" was omitted from the amended clearance,
it is no longer in effect.
Pilots of turbojet aircraft equipped
with afterburner engines should advise ATC prior to
takeoff if they intend to use afterburning during
their climb to the en route altitude. Often, the
controller may be able to plan traffic to accommodate
a high performance climb and allow the aircraft to
climb to the planned altitude without restriction.
If an "expedite" climb or descent
clearance is issued by ATC, and the altitude to
maintain is subsequently changed or restated without
an expedite instruction, the expedite instruction is
canceled. Expedite climb/descent normally indicates to
the pilot that the approximate best rate of
climb/descent should be used without requiring an
exceptional change in aircraft handling
characteristics. Normally controllers will inform
pilots of the reason for an instruction to expedite.
ATC effects separation of aircraft
vertically by assigning different altitudes;
longitudinally by providing an interval expressed in
time or distance between aircraft on the same,
converging, or crossing courses, and laterally by
assigning different flight paths.
Separation will be provided between all
aircraft operating on IFR flight plans except during
that part of the flight (outside Class B airspace or a
TRSA) being conducted on a VFR-on-top/VFR conditions
clearance. Under these conditions, ATC may issue
traffic advisories, but it is the sole responsibility
of the pilot to be vigilant so as to see and avoid
When radar is employed in the
separation of aircraft at the same altitude, a minimum
of 3 miles separation is provided between aircraft
operating within 40 miles of the radar antenna site,
and 5 miles between aircraft operating beyond 40 miles
from the antenna site. These minima may be increased
or decreased in certain specific situations.
Certain separation standards are increased in the
terminal environment when CENRAP is being utilized.
4-4-11. Speed Adjustments
ATC will issue speed adjustments to
pilots of radar-controlled aircraft to achieve or
maintain required or desire spacing.
ATC will express all speed adjustments
in terms of knots based on indicated airspeed (IAS) in
10 knot increments except that at or above FL 240
speeds may be expressed in terms of Mach numbers in
0.01 increments. The use of Mach numbers is restricted
to turbojet aircraft with Mach meters.
Pilots complying with speed adjustments
are expected to maintain a speed within plus or minus
10 knots or 0.02 Mach number of the specified speed.
Unless pilot concurrence is obtained,
ATC requests for speed adjustments will be in
accordance with the following minimums:
To aircraft operating between FL 280
and 10,000 feet, a speed not less than 250 knots or
the equivalent Mach number.
To turbine-powered aircraft operating
below 10,000 feet:
A speed not less than 210 knots,
Within 20 flying miles of the
airport of intended landing, a speed not less than
Reciprocating engine or turboprop
aircraft within 20 flying miles of the runway
threshold of the airport of intended landing, a
speed not less than 150 knots.
To departing aircraft:
Turbine-powered aircraft, a speed
not less than 230 knots.
Reciprocating engine aircraft, a
speed not less than 150 knots.
When ATC combines a speed adjustment
with a descent clearance, the sequence of delivery,
with the word "then" between, indicates the expected
order of execution.
1. Descend and
maintain (altitude); then, reduce speed to (speed).
2. Reduce speed to (speed); then,
descend and maintain (altitude).
The maximum speeds below 10,000 feet as established in
14 CFR Section 91.117 still apply. If there is any
doubt concerning the manner in which such a clearance
is to be executed, request clarification from ATC.
If ATC determines (before an approach
clearance is issued) that it is no longer necessary to
apply speed adjustment procedures, they will inform
the pilot to resume normal speed. Approach clearances
supersede any prior speed adjustment assignments, and
pilots are expected to make their own speed
adjustments, as necessary, to complete the approach.
Under certain circumstances, however, it may be
necessary for ATC to issue further speed adjustments
after approach clearance is issued to maintain
separation between successive arrivals. Under such
circumstances, previously issued speed adjustments
will be restated if that speed is to be maintained or
additional speed adjustments are requested. ATC must
obtain pilot concurrence for speed adjustments after
approach clearances are issued. Speed adjustments
should not be assigned inside the final approach fix
on final or a point 5 miles from the runway, whichever
is closer to the runway.
The pilots retain the prerogative of
rejecting the application of speed adjustment by ATC
if the minimum safe airspeed for any particular
operation is greater than the speed adjustment.
In such cases, pilots are expected to advise ATC of
the speed that will be used.
Pilots are reminded that they are
responsible for rejecting the application of speed
adjustment by ATC if, in their opinion, it will cause
them to exceed the maximum indicated airspeed
prescribed by 14 CFR Section 91.117(a), (c) and (d).
IN SUCH CASES, THE PILOT IS EXPECTED TO SO INFORM
ATC. Pilots operating at or above 10,000 feet MSL
who are issued speed adjustments which exceed 250
knots IAS and are subsequently cleared below 10,000
feet MSL are expected to comply with 14 CFR Section
Speed restrictions of 250 knots do not
apply to U.S. registered aircraft operating beyond 12
nautical miles from the coastline within the U.S.
Flight Information Region, in Class E airspace below
10,000 feet MSL. However, in airspace underlying a
Class B airspace area designated for an airport, or in
a VFR corridor designated through such as a Class B
airspace area, pilots are expected to comply with the
200 knot speed limit specified in 14 CFR Section
For operations in a Class C and Class D
surface area, ATC is authorized to request or approve
a speed greater than the maximum indicated airspeeds
prescribed for operation within that airspace (14 CFR
Pilots are expected to comply with the maximum speed
of 200 knots when operating beneath Class B airspace
or in a Class B VFR corridor (14 CFR Section 91.117(c)
When in communications with the ARTCC
or approach control facility, pilots should, as a good
operating practice, state any ATC assigned speed
restriction on initial radio contact associated with
an ATC communications frequency change.
4-4-12. Runway Separation
establish the sequence of arriving and departing
aircraft by requiring them to adjust flight or ground
operation as necessary to achieve proper spacing. They
may "HOLD" an aircraft short of the runway to achieve
spacing between it and an arriving aircraft; the
controller may instruct a pilot to "EXTEND DOWNWIND" in
order to establish spacing from an arriving or departing
aircraft. At times a clearance may include the word
"IMMEDIATE." For example: "CLEARED FOR IMMEDIATE
TAKEOFF." In such cases "IMMEDIATE" is used for purposes
of air traffic separation. It is up to the pilot
to refuse the clearance if, in the pilot's opinion,
compliance would adversely affect the operation.
AIM, Gate Holding due to Departure Delays, Paragraph
4-4-13. Visual Separation
Visual separation is a means employed
by ATC to separate aircraft in terminal areas and en
route airspace in the NAS. There are two methods
employed to effect this separation:
The tower controller sees the
aircraft involved and issues instructions, as
necessary, to ensure that the aircraft avoid each
A pilot sees the other aircraft
involved and upon instructions from the controller
provides separation by maneuvering the aircraft to
avoid it. When pilots accept responsibility to
maintain visual separation, they must maintain
constant visual surveillance and not pass the other
aircraft until it is no longer a factor.
Traffic is no longer a factor when during approach
phase the other aircraft is in the landing phase of
flight or executes a missed approach; and during
departure or en route, when the other aircraft turns
away or is on a diverging course.
A pilot's acceptance of instructions to
follow another aircraft or provide visual separation
from it is an acknowledgment that the pilot will
maneuver the aircraft as necessary to avoid the other
aircraft or to maintain in-trail separation. In
operations conducted behind heavy jet aircraft, it is
also an acknowledgment that the pilot accepts the
responsibility for wake turbulence separation.
When a pilot has been told to follow another aircraft
or to provide visual separation from it, the pilot
should promptly notify the controller if visual
contact with the other aircraft is lost or cannot be
maintained or if the pilot cannot accept the
responsibility for the separation for any reason.
Scanning the sky for other aircraft is
a key factor in collision avoidance. Pilots and
copilots (or the right seat passenger) should
continuously scan to cover all areas of the sky
visible from the cockpit. Pilots must develop an
effective scanning technique which maximizes one's
visual capabilities. Spotting a potential collision
threat increases directly as more time is spent
looking outside the aircraft. One must use timesharing
techniques to effectively scan the surrounding
airspace while monitoring instruments as well.
Since the eye can focus only on a
narrow viewing area, effective scanning is
accomplished with a series of short, regularly spaced
eye movements that bring successive areas of the sky
into the central visual field. Each movement should
not exceed ten degrees, and each area should be
observed for at least one second to enable collision
detection. Although many pilots seem to prefer the
method of horizontal back-and-forth scanning every
pilot should develop a scanning pattern that is not
only comfortable but assures optimum effectiveness.
Pilots should remember, however, that they have a
regulatory responsibility (14 CFR Section 91.113(a))
to see and avoid other aircraft when weather
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4-4-14. Use of Visual Clearing
a. Before Takeoff.
Prior to taxiing onto a
runway or landing area in preparation for takeoff,
pilots should scan the approach areas for possible
landing traffic and execute the appropriate clearing
maneuvers to provide them a clear view of the approach
b. Climbs and
Descents. During climbs and
descents in flight conditions which permit visual
detection of other traffic, pilots should execute
gentle banks, left and right at a frequency which
permits continuous visual scanning of the airspace
c. Straight and
Level. Sustained periods of
straight and level flight in conditions which permit
visual detection of other traffic should be broken at
intervals with appropriate clearing procedures to
provide effective visual scanning.
d. Traffic Pattern.
Entries into traffic
patterns while descending create specific collision
hazards and should be avoided.
e. Traffic at VOR
Sites. All operators should
emphasize the need for sustained vigilance in the
vicinity of VOR's and airway intersections due to the
convergence of traffic.
Operations. Operators of
pilot training programs are urged to adopt the
Pilots undergoing flight instruction
at all levels should be requested to verbalize
clearing procedures (call out "clear" left, right,
above, or below) to instill and sustain the habit of
vigilance during maneuvering.
raise the wing in the direction of the intended turn
Momentarily lower the wing in the direction of the
intended turn and look.
Appropriate clearing procedures
should precede the execution of all turns including
chandelles, lazy eights, stalls, slow flight,
climbs, straight and level, spins, and other
4-4-15. Traffic Alert and
Collision Avoidance System (TCAS I & II)
a. TCAS I
provides proximity warning only, to assist the pilot
in the visual acquisition of intruder aircraft. No
recommended avoidance maneuvers are provided nor
authorized as a direct result of a TCAS I warning. It
is intended for use by smaller commuter aircraft
holding 10 to 30 passenger seats, and general aviation
b. TCAS II
provides traffic advisories (TA's) and resolution
advisories (RA's). Resolution advisories provide
recommended maneuvers in a vertical direction (climb
or descend only) to avoid conflicting traffic. Airline
aircraft, and larger commuter and business aircraft
holding 31 passenger seats or more, use TCAS II
Each pilot who deviates from an ATC
clearance in response to a TCAS II RA shall notify
ATC of that deviation as soon as practicable and
expeditiously return to the current ATC clearance
when the traffic conflict is resolved.
Deviations from rules, policies, or
clearances should be kept to the minimum necessary
to satisfy a TCAS II RA.
The serving IFR air traffic facility
is not responsible to provide approved standard IFR
separation to an aircraft after a TCAS II RA
maneuver until one of the following conditions
The aircraft has returned to its
assigned altitude and course.
Alternate ATC instructions have
TCAS does not alter or diminish the
pilot's basic authority and responsibility to ensure
safe flight. Since TCAS does not respond to aircraft
which are not transponder equipped or aircraft with a
transponder failure, TCAS alone does not ensure safe
separation in every case.
At this time, no air traffic service
nor handling is predicated on the availability of TCAS
equipment in the aircraft.