4/20/23 

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

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in

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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 

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

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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

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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

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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 

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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. 

ATC Clearances and Aircraft Separation 

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