Pilot/Controller Glossary 

11/3/22 

specified limits. These areas may be required for 
certain turbine-powered operations and the size and 
upward slope of the clearway will differ depending on 
when the aircraft was certificated. 

(Refer to 14 CFR Part 1.) 

CLIMB TO VFR

−

 ATC authorization for an aircraft 

to climb to VFR conditions within Class B, C, D, and 
E surface areas when the only weather limitation is 
restricted visibility. The aircraft must remain clear of 
clouds while climbing to VFR. 

(See SPECIAL VFR CONDITIONS.) 
(Refer to AIM.) 

CLIMBOUT

−

 That portion of flight operation 

between takeoff and the initial cruising altitude. 

CLIMB VIA– An abbreviated ATC clearance that 
requires compliance with the procedure lateral path, 
associated speed restrictions, and altitude restrictions 
along the cleared route or procedure. 

CLOSE PARALLEL RUNWAYS

−

 Two parallel 

runways whose extended centerlines are separated by 
less than 4,300 feet and at least 3000 feet (750 feet for 
SOIA operations) for which ATC is authorized to 
conduct simultaneous independent approach opera-
tions. PRM and simultaneous close parallel appear in 
approach title. Dual communications, special pilot 
training, an Attention All Users Page (AAUP), NTZ 
monitoring by displays that have aural and visual 
alerting algorithms are required. A high update rate 
surveillance sensor is required for certain runway or 
approach course spacing. 

CLOSED LOOP CLEARANCE

−

 A vector or reroute 

clearance that includes a return to route point and 
updates ERAM to accurately reflect the anticipated 
route (e.g., a QU route pick that anticipates length of 
vector and includes the next fix that ties into the route 
of flight.) 

CLOSED RUNWAY

−

 A runway that is unusable for 

aircraft operations. Only the airport management/ 
military operations office can close a runway. 

CLOSED TRAFFIC

−

 Successive operations involv-

ing takeoffs and landings or low approaches where 
the aircraft does not exit the traffic pattern. 

CLOUD

−

 A cloud is a visible accumulation of 

minute water droplets and/or ice particles in the 
atmosphere above the Earth’s surface. Cloud differs 
from ground fog, fog, or ice fog only in that the latter 
are, by definition, in contact with the Earth’s surface. 

CLT

−

 

(See CALCULATED LANDING TIME.) 

CLUTTER

−

 In radar operations, clutter refers to the 

reception and visual display of radar returns caused 
by precipitation, chaff, terrain, numerous aircraft 
targets, or other phenomena. Such returns may limit 
or preclude ATC from providing services based on 
radar. 

(See CHAFF.) 
(See GROUND CLUTTER.) 
(See PRECIPITATION.) 
(See TARGET.) 
(See ICAO term RADAR CLUTTER.) 

CMNPS

−

 

(See CANADIAN MINIMUM NAVIGATION 

PERFORMANCE SPECIFICATION AIRSPACE.) 

COA

−

 

(See CERTIFICATE OF WAIVER OR 

AUTHORIZATION.) 

COASTAL FIX

−

 A navigation aid or intersection 

where an aircraft transitions between the domestic 
route structure and the oceanic route structure. 

CODES

−

 The number assigned to a particular 

multiple pulse reply signal transmitted by a 
transponder. 

(See DISCRETE CODE.) 

COLD TEMPERATURE CORRECTION

−

 A 

correction in feet, based on height above airport and 
temperature, that is added to the aircraft’s indicated 
altitude to offset the effect of cold temperature on true 
altitude. 

COLLABORATIVE TRAJECTORY OPTIONS 
PROGRAM (CTOP)

−

 CTOP is a traffic management 

program administered by the Air Traffic Control 
System Command Center (ATCSCC) that manages 
demand through constrained airspace, while consid-
ering operator preference with regard to both route 
and delay as defined in a Trajectory Options Set 
(TOS). 

COMBINED CENTER-RAPCON

−

 An air traffic 

facility which combines the functions of an ARTCC 
and a radar approach control facility. 

(See AIR ROUTE TRAFFIC CONTROL 

CENTER.) 

(See RADAR APPROACH CONTROL 

FACILITY.) 

COMMON POINT

−

 A significant point over which 

two or more aircraft will report passing or have 

PCG C

−

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