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6/17/21 

AIM 

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

 

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

 

AIM, Paragraph 5

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5, Abbreviated IFR Departure Clearance 

(Cleared. . .as Filed) Procedures 
AIM, Paragraph 5

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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 

ATC Clearances and Aircraft Separation 

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