(2)
CONTROL ZONE (JCS, NATO, ICAO) - A controlled airspace extending upwards from the surface of the earth to a specified upper limit.

(3)
TERMINAL CONTROL AREA (JCS) - A control area or a portion thereof normally situated at the confluence of air traffic service routes in the vicinity of one or more major airfields.

(4)
TERMINAL CONTROL AREA (NATO, ICAO) - A control area normally established at the confluence of Air Traffic Service (ATS) routes in the vicinity of one or more major airfields (aerodromes).

NOTE: Refer to ICAO Annex II for definition of controlled airspace classes.
CONTROLLED DEPARTURE TIME (CDT) PROGRAMS - These programs are the flow control process whereby aircraft are held on the ground at the departure airport when delays are projected to occur in either the enroute system or the terminal of intended landing. The purpose of these programs is to reduce congestion in the air traffic system or to limit the duration of airborne holding in the arrival center or terminal area. A CDT is a specific departure slot shown on the flight plan as an expected departure clearance time (EDCT).
CONTROLLER - (See Air Traffic Control Specialist)
CONTROLLER PILOT DATA LINK COMMUNICATIONS (CPDLC) - Provides services to FANS-1 (or other format compatible to FANS-1) equipped aircraft beyond the range of existing radar and VHF voice communications through satellite data links. Provides emergency alerting, Pilot-to-Controller down link of position reports and clearance request, Controller-to-Pilot up link of ATC clearances and instructions and free text as a supplement to pre-formatted message elements.
CONVECTIVE SIGMET/WST/CONVECTIVE SIGNIFICANT METEOROLOGICAL INFORMATION - 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 percent) or more, and hail 3/4 inch or greater. (See SIGMET, Center Weather Advisory, Severe Weather Forecast Alerts, and AIRMET).
COORDINATED UNIVERSAL TIME/COORDINATED UNIVERSAL TIME (NGA) - Mean solar time at the meridian of Greenwich, England, used as a basis for standard time throughout the world. Normally expressed in four numerals 0001 through 2400. Also called Greenwich Mean Time; GMT; Greenwich civil time; universal time; Z-time; Zulu time.
COORDINATES (P/CG) - The intersection of lines of reference, usually expressed in degrees/minutes/seconds of latitude and longitude, used to determine position or location.