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Pilot/Controller Glossary 

CHASE AIRCRAFT

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(See CHASE.) 

CHOP

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 A form of turbulence. 

a. 

Light Chop– Turbulence that causes slight, rapid and somewhat rhythmic bumpiness without appreciable 

changes in altitude or attitude. 

b. 

Moderate Chop– Turbulence similar to Light Chop but of greater intensity. It causes rapid bumps or jolts 

without appreciable changes in aircraft altitude or attitude. 

(See TURBULENCE.) 

CIRCLE-TO-LAND MANEUVER

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 A maneuver initiated by the pilot to align the aircraft with a runway for 

landing when a straight-in landing from an instrument approach is not possible or is not desirable. At tower 

controlled airports, this maneuver is made only after ATC authorization has been obtained and the pilot has 

established required visual reference to the airport. 

(See CIRCLE TO RUNWAY.) 
(See LANDING MINIMUMS.) 
(Refer to AIM.) 

CIRCLE TO RUNWAY (RUNWAY NUMBER)

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Used by ATC to inform the pilot that he/she must circle to 

land because the runway in use is other than the runway aligned with the instrument approach procedure. When 

the direction of the circling maneuver in relation to the airport/runway is required, the controller will state the 

direction (eight cardinal compass points) and specify a left or right downwind or base leg as appropriate; e.g., 

“Cleared VOR Runway Three Six Approach circle to Runway Two Two,” or “Circle northwest of the airport 

for a right downwind to Runway Two Two.” 

(See CIRCLE-TO-LAND MANEUVER.) 
(See LANDING MINIMUMS.) 
(Refer to AIM.) 

CIRCLING APPROACH

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(See CIRCLE-TO-LAND MANEUVER.) 

CIRCLING MANEUVER

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(See CIRCLE-TO-LAND MANEUVER.) 

CIRCLING MINIMA

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(See CONTROLLED AIRSPACE.) 

CIVIL AIRCRAFT OPERATION (CAO)

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 Aircraft operations other than public use. 

CLASS A AIRSPACE

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(See CONTROLLED AIRSPACE.) 

CLASS B AIRSPACE

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(See CONTROLLED AIRSPACE.) 

CLASS C AIRSPACE

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(See CONTROLLED AIRSPACE.) 

CLASS D AIRSPACE

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(See CONTROLLED AIRSPACE.) 

CLASS E AIRSPACE

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(See CONTROLLED AIRSPACE.) 

CLASS G AIRSPACE

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 Airspace that is not designated in 14 CFR Part 71 as Class A, Class B, Class C, Class 

D, or Class E controlled airspace is Class G (uncontrolled) airspace. 

(See UNCONTROLLED AIRSPACE.) 

PCG C

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