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AIM

10/12/17

4−4−1

ATC Clearances and Aircraft Separation

Section 4. ATC Clearances and Aircraft Separation

4−4−1. 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.

4−4−2. 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.”

4−4−3. 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 5−2−5, Abbreviated IFR Departure Clearance

(Cleared. . .as Filed) Procedures

AIM, Paragraph 5−2−9 , 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