Aviation and air traffic control terminology · MLC-0104
Aviation and air traffic control terms: C (110)
- Calculated landing timeA term that may be used in place of tentative or actual calculated landing time, whichever applies.
- Calibrated airspeed (CAS)The indicated airspeed of an aircraft, corrected for position and instrument error. Calibrated airspeed is...
- Call for releaseWherein the overlying ARTCC requires a terminal facility to initiate verbal coordination to secure ARTCC...
- Call upInitial voice contact between a facility and an aircraft, using the identification of the unit being called...
- Canadian minimum navigation performance specification airspaceThat portion of Canadian domestic airspace within which MNPS separation may be applied.
- Cardinal altitudes“Odd” or “Even” thousand-foot altitudes or flight levels; e.g., 5,000, 6,000, 7,000, FL 250, FL 260, FL 270.
- Cardinal flight levels, see Cardinal altitudes
- CAT, see Clear air turbulence (CAT)
- Catch pointA fix/waypoint that serves as a transition point from the high altitude waypoint navigation structure to an...
- CBO, see Community-based organization (CBO)
- CCF, see Combined control facility (CCF)
- CeilingThe heights above the earth's surface of the lowest layer of clouds or obscuring phenomena that is reported...
- Ceiling [ICAO]The height above the ground or water of the base of the lowest layer of cloud below 6,000 meters (20,000...
- Center, see Air route traffic control center (ARTCC)
- Center weather advisoryAn unscheduled weather advisory issued by Center Weather Service Unit meteorologists for ATC use to alert...
- Center's areaThe specified airspace within which an air route traffic control center (ARTCC) provides air traffic control...
- Central East PacificAn organized route system between the U.S. West Coast and Hawaii.
- CEP, see Central East Pacific
- Certificate of waiver or authorization (COA)An FAA grant of approval for a specific flight operation or airspace authorization or waiver.
- Certified tower radar display (CTRD)An FAA radar display certified for use in the NAS.
- CFR, see Call for release
- CHA, see Contingency hazard area (CHA)
- ChaffThin, narrow metallic reflectors of various lengths and frequency responses, used to reflect radar energy...
- Chart SupplementA series of civil/military flight information publications issued by FAA every 56 days consisting of the...
- Chart Supplement AlaskaA flight information publication designed for use with appropriate IFR or VFR charts which contains data on...
- Chart Supplement PacificA flight information publication designed for use with appropriate IFR or VFR charts which contains data on...
- Chart Supplement U.S.A flight information publication designed for use with appropriate IFR or VFR charts which contains data on...
- Charted VFR flywaysCharted VFR Flyways are flight paths recommended for use to bypass areas heavily traversed by large...
- Charted visual flight procedure approachAn approach conducted while operating on an instrument flight rules (IFR) flight plan which authorizes the...
- ChaseAn aircraft flown in proximity to another aircraft normally to observe its performance during training or...
- Chase aircraft, see Chase
- ChopA form of turbulence.
- Circle to runway (runway number)Used by ATC to inform the pilot that he/she must circle to land because the runway in use is other than the...
- Circle-to-land maneuverA maneuver initiated by the pilot to align the aircraft with a runway for landing when a straight-in landing...
- Circling approach, see Circle-to-land maneuver
- Circling maneuver, see Circle-to-land maneuver
- Circling minima, see Controlled airspace
- Civil aircraft operation (CAO)Aircraft operations other than public use.
- Class A airspace, see Controlled airspace
- Class B airspace, see Controlled airspace
- Class C airspace, see Controlled airspace
- Class D airspace, see Controlled airspace
- Class E airspace, see Controlled airspace
- Class G airspaceAirspace that is not designated in 14 CFR part 71 as Class A, Class B, Class C, Class D, or Class E...
- Clear air turbulence (CAT)Turbulence encountered in air where no clouds are present. This term is commonly applied to high-level...
- Clear of the runwaya. Taxiing aircraft, which is approaching a runway, is clear of the runway when all parts of the aircraft are...
- Clearance, see Air traffic clearance
- Clearance limitThe fix, point, or location to which an aircraft is cleared when issued an air traffic clearance.
- Clearance limit [ICAO]The point to which an aircraft is granted an air traffic control clearance.
- Clearance void if not off by (time)Used by ATC to advise an aircraft that the departure release is automatically canceled if takeoff is not made...
- Clearance void time [ICAO]A time specified by an air traffic control unit at which a clearance ceases to be valid unless the aircraft...
- Cleared approachATC authorization for an aircraft to execute any standard or special instrument approach procedure for that...
- Cleared as filedMeans the aircraft is cleared to proceed in accordance with the route of flight filed in the flight plan...
- Cleared for takeoffATC authorization for an aircraft to depart. It is predicated on known traffic and known physical airport...
- Cleared for the optionATC authorization for an aircraft to make a touch-and-go, low approach, missed approach, stop and go, or full...
- Cleared throughATC authorization for an aircraft to make intermediate stops at specified airports without refiling a flight...
- Cleared to landATC authorization for an aircraft to land. It is predicated on known traffic and known physical airport...
- Cleared (type of) approachATC authorization for an aircraft to execute a specific instrument approach procedure to an airport; e.g...
- ClearwayAn area beyond the takeoff runway under the control of airport authorities within which terrain or fixed...
- Climb to VFRATC authorization for an aircraft to climb to VFR conditions within Class B, C, D, and E surface areas when...
- Climb viaAn abbreviated ATC clearance that requires compliance with the procedure lateral path, associated speed...
- ClimboutThat portion of flight operation between takeoff and the initial cruising altitude.
- Close parallel runwaysTwo parallel runways whose extended centerlines are separated by less than 4,300 feet and at least 3000 feet...
- Closed loop clearanceA vector or reroute clearance that includes a return to route point and updates ERAM to accurately reflect...
- Closed runwayA runway that is unusable for aircraft operations. Only the airport management/military operations office can...
- Closed trafficSuccessive operations involving takeoffs and landings or low approaches where the aircraft does not exit the...
- CloudA cloud is a visible accumulation of minute water droplets and/or ice particles in the atmosphere above the...
- CLT, see Calculated landing time
- ClutterIn radar operations, clutter refers to the reception and visual display of radar returns caused by...
- CMNPS, see Canadian minimum navigation performance specification airspace
- COA, see Certificate of waiver or authorization (COA)
- Coastal fixA navigation aid or intersection where an aircraft transitions between the domestic route structure and the...
- CodesThe number assigned to a particular multiple pulse reply signal transmitted by a transponder.
- Cold temperature correctionA correction in feet, based on height above airport and temperature, that is added to the aircraft's...
- Collaborative trajectory options program (CTOP)CTOP is a traffic management program administered by the Air Traffic Control System Command Center (ATCSCC)...
- Combined control facility (CCF)An air traffic facility that combines the functions of an ARTCC and a radar approach control facility.
- Common pointA significant point over which two or more aircraft will report passing or have reported passing before...
- Common portion, see Common route
- Common routeThat segment of a North American Route between the inland navigation facility and the coastal fix.
- Common traffic advisory frequency (CTAF)A frequency designed for the purpose of carrying out airport advisory practices while operating to or from an...
- Community-based organization (CBO)A membership-based entity, described under Section 501(a,c), whose mission is the furtherance of model...
- Compass locatorA low power, low or medium frequency (L/MF) radio beacon installed at the site of the outer or middle marker...
- Compass roseA circle, graduated in degrees, printed on some charts or marked on the ground at an airport. It is used as a...
- Comply with restrictionsAn ATC instruction that requires an aircraft being vectored back onto an arrival or departure procedure to...
- Composite flight planA flight plan which specifies VFR operation for one portion of flight and IFR for another portion. It is used...
- Compulsory reporting pointsReporting points which must be reported to ATC. They are designated on aeronautical charts by solid triangles...
- Computer navigation fix (CNF)A Computer Navigation Fix is a point defined by a latitude/longitude coordinate and is required to support...
- Conditions not monitoredWhen an airport operator cannot monitor the condition of the movement area or airfield surface area, this...
- Confidence maneuverA confidence maneuver consists of one or more turns, a climb or descent, or other maneuver to determine if...
- Conflict alertA function of certain air traffic control automated systems designed to alert radar controllers to existing...
- Conflict resolutionThe resolution of potential conflictions between aircraft that are radar identified and in communication with...
- ConformanceThe condition established when an aircraft's actual position is within the conformance region constructed...
- Conformance regionA volume, bounded laterally, vertically, and longitudinally, within which an aircraft must be at a given time...
- ConnectionA virtual connection between the ground system and the aircraft for the exchange of CPDLC messages.
- ConsolanA low frequency, long-distance NAVAID used principally for transoceanic navigations.
- Constraint satisfaction point (CSP)Meter Reference Elements (MREs) that are actively scheduled by TBFM. Constraint satisfaction occurs when the...
- Contacta. Establish communication with (followed by the name of the facility and, if appropriate, the frequency to...
- Contact approachAn approach wherein an aircraft on an IFR flight plan, having an air traffic control authorization, operating...
- Contaminated runwayA runway is considered contaminated whenever standing water, ice, snow, slush, frost in any form, heavy...
- Conterminous U.S.The 48 adjoining States and the District of Columbia.
- Continental United StatesThe 49 States located on the continent of North America and the District of Columbia.
- Contingency hazard area (CHA)Used by ATC. Areas of airspace that are defined and distributed in advance of a launch or reentry operation...
- ContinueWhen used as a control instruction should be followed by another word or words clarifying what is expected of...
- Control area [ICAO]A controlled airspace extending upwards from a specified limit above the earth.
- Control sectorAn airspace area of defined horizontal and vertical dimensions for which a controller or group of controllers...
- Control slashA radar beacon slash representing the actual position of the associated aircraft. Normally, the control slash...
- Controlled airspaceAn airspace of defined dimensions within which air traffic control service is provided to IFR flights and to...
- Controlled airspace [ICAO]An airspace of defined dimensions within which air traffic control service is provided to IFR flights and to...
- Controlled time of arrivalArrival time assigned during a Traffic Management Program. This time may be modified due to adjustments or...
- 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...
- Convective SIGMETA weather advisory concerning convective weather significant to the safety of all aircraft. Convective...
- Convective significant meteorological information, see Convective SIGMET
- Cooperative surveillanceAny surveillance system, such as secondary surveillance radar (SSR), wide-area multilateration (WAM), or...
- CoordinatesThe intersection of lines of reference, usually expressed in degrees/minutes/seconds of latitude and...
- Coordination fixThe fix in relation to which facilities will handoff, transfer control of an aircraft, or coordinate flight...
- Copter, see Helicopter
- CorrectionAn error has been made in the transmission and the correct version follows.
- Coupled approachAn instrument approach performed by the aircraft autopilot, and/or visually depicted on the flight director...
- Coupled scheduling (CS)/ extended metering (XM)Adds additional Constraint Satisfaction Points for metered aircraft along their route. This provides the...
- Coursea. The intended direction of flight in the horizontal plane measured in degrees from north.
- CPDLC, see Controller pilot data link communications (CPDLC)
- CPL [ICAO], see Current flight plan [ICAO]
- Crewmember (UAS)A person assigned to perform an operational duty. A UAS crewmember includes the remote pilot in command, the...
- Critical engineThe engine which, upon failure, would most adversely affect the performance or handling qualities of an...
- 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 is required. It does not prohibit the aircraft...
- Cross (fix) at or below (altitude)Used by ATC when a maximum crossing altitude at a specific fix is required. It does not prohibit the aircraft...
- Crosswinda. When used concerning the traffic pattern, the word means “crosswind leg.”
- Crosswind componentThe wind component measured in knots at 90 degrees to the longitudinal axis of the runway.
- CruiseUsed in an ATC clearance to authorize a pilot to conduct flight at any altitude from the minimum IFR altitude...
- Cruise climbA climb technique employed by aircraft, usually at a constant power setting, resulting in an increase of...
- Cruising altitudeAn altitude or flight level maintained during en route level flight. This is a constant altitude and should...
- Cruising level, see Cruising altitude
- Cruising level [ICAO]A level maintained during a significant portion of a flight.
- CSP, see Constraint satisfaction point (CSP)
- CT messageAn EDCT time generated by the ATCSCC to regulate traffic at arrival airports. Normally, a CT message is...
- CTA, see Controlled time of arrival; Control area [ICAO]
- CTAF, see Common traffic advisory frequency (CTAF)
- CTOP, see Collaborative trajectory options program (CTOP)
- CTRD, see Certified tower radar display (CTRD)
- Current flight plan [ICAO]The flight plan, including changes, if any, brought about by subsequent clearances.
- CVFP approach, see Charted visual flight procedure approach
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