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Pilot/Controller Glossary 

6/17/21 

service is provided to IFR flights and to VFR flights 
in accordance with the airspace classification. 

Note: Controlled airspace is a generic term which 

covers ATS airspace Classes A, B, C, D, and E. 

CONTROLLED TIME OF ARRIVAL

 Arrival time 

assigned during a Traffic Management Program. This 
time may be modified due to adjustments or user 
options. 

CONTROLLER

 

(See AIR TRAFFIC CONTROL SPECIALIST.) 

CONTROLLER [ICAO]

 A person authorized to 

provide air traffic control services. 

CONTROLLER PILOT DATA LINK 
COMMUNICATIONS (CPDLC)

 A two

way 

digital communications system that conveys textual 
air traffic control messages between controllers and 
pilots using ground or satellite-based radio relay 
stations. 

CONVECTIVE SIGMET

  A weather advisory 

concerning convective weather significant to the 
safety of all aircraft. Convective SIGMETs are issued 
for tornadoes, lines of thunderstorms, embedded 
thunderstorms of any intensity level, areas of 
thunderstorms greater than or equal to VIP level 4 
with an area coverage of 

4

/

10

 (40%) or more, and hail 

3

/

4

 inch or greater. 

(See AIRMET.) 
(See AWW.) 
(See CWA.) 
(See SIGMET.) 
(Refer to AIM.) 

CONVECTIVE SIGNIFICANT METEOROLOG-
ICAL INFORMATION

 

(See CONVECTIVE SIGMET.) 

COOPERATIVE SURVEILLANCE

 Any surveil-

lance system, such as secondary surveillance radar 
(SSR), wide

area multilateration (WAM), or ADS

 

B, that is dependent upon the presence of certain 
equipment onboard the aircraft or vehicle to be 
detected. 

(See AUTOMATIC DEPENDENT 

SURVEILLANCE

BROADCAST.) 

(See NON

COOPERATIVE SURVEILLANCE.) 

(See RADAR.) 
(See WIDE AREA MULTILATERATION.) 

COORDINATES

 The intersection of lines of 

reference, usually expressed in degrees/minutes/ 

seconds of latitude and longitude, used to determine 
position or location. 

COORDINATION FIX

 The fix in relation to which 

facilities will handoff, transfer control of an aircraft, 
or coordinate flight progress data. For terminal 
facilities, it may also serve as a clearance for arriving 
aircraft. 

COPTER

 

(See HELICOPTER.) 

CORRECTION

 An error has been made in the 

transmission and the correct version follows. 

COUPLED APPROACH

 An instrument approach 

performed by the aircraft autopilot, and/or visually 
depicted on the flight director, which is receiving 
position information and/or steering commands from 
onboard navigational equipment. In general, coupled 
non-precision approaches must be flown manually 
(autopilot disengaged) at altitudes lower than 50 feet 
AGL below the minimum descent altitude, and 
coupled precision approaches must be flown 
manually (autopilot disengaged) below 50 feet AGL 
unless authorized to conduct autoland operations. 
Coupled instrument approaches are commonly flown 
to the allowable IFR weather minima established by 
the operator or PIC, or flown VFR for training and 
safety. 

COURSE

 

a. 

The intended direction of flight in the horizontal 

plane measured in degrees from north. 

b. 

The ILS localizer signal pattern usually 

specified as the front course or the back course. 

(See BEARING.) 
(See INSTRUMENT LANDING SYSTEM.) 
(See RADIAL.) 

CPDLC

 

(See CONTROLLER PILOT DATA LINK 

COMMUNICATIONS.) 

CPL [ICAO]

 

(See ICAO term CURRENT FLIGHT PLAN.) 

CRITICAL ENGINE

 The engine which, upon 

failure, would most adversely affect the performance 
or handling qualities of an aircraft. 

CROSS (FIX) AT (ALTITUDE)

  Used by ATC 

when a specific altitude restriction at a specified fix 
is required. 

CROSS (FIX) AT OR ABOVE (ALTITUDE)

 Used 

by ATC when an altitude restriction at a specified fix 

PCG C