AIM
4/3/14
4−4−1
ATC Clearances and Aircraft Separation
Section 4. ATC Clearances and Aircraft Separation
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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. Simi-
larly, 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
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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.
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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.”
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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 NAVAIDs 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 NAVAID or
other fix. When the clearance limit is a NAVAID,
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.
REFERENCE
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AIM, Abbreviated IFR Departure Clearance (Cleared. . .as Filed)
Procedures, Paragraph 5
−2−5.
AIM, Instrument Departure Procedures (DP)
− Obstacle Departure
Procedures (ODP) and Standard Instrument Departures (SID),
Paragraph 5
−2−8.
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