Aviation and air traffic control terminology · MLC-0104

Aviation and air traffic control terms: D (52)

• DA [ICAO], see Decision altitude/decision height [ICAO Annex 6]
• Danger area [ICAO]An airspace of defined dimensions within which activities dangerous to the flight of aircraft may exist at...
• DAS, see Delay assignment (DAS)
• Data block, see Alphanumeric display
• Data link automatic terminal information service (D-ATIS) [ICAO]The provision of ATIS via data link.
• D-ATIS, see Digital-automatic terminal information service (D-ATIS)
• D-ATIS [ICAO], see Data link automatic terminal information service (D-ATIS) [ICAO]
• DCL, see Departure clearance (DCL) application
• DCT, see Delay countdown timer (DCT)
• Dead reckoningDead reckoning, as applied to flying, is the navigation of an airplane solely by means of computations based...
• Debris response area (DRA)Used by ATC. Areas of airspace that may be activated in response to unplanned falling debris in the NAS.
• Decision altitude (DA)A specified altitude (mean sea level (MSL)) on an instrument approach procedure (ILS, GLS, vertically guided...
• Decision altitude/decision height [ICAO Annex 6]A specified altitude or height (A/H) in the precision approach at which a missed approach must be initiated...
• Decision height (DH)With respect to the operation of aircraft, means the height at which a decision must be made during an ILS or...
• DecoderThe device used to decipher signals received from ATCRBS transponders to effect their display as select codes.
• Defense areaAny airspace of the contiguous United States that is not an ADIZ in which the control of aircraft is required...
• Defense visual flight rulesRules applicable to flights within an ADIZ conducted under the visual flight rules in 14 CFR part 91.
• Delay assignment (DAS)Delays are distributed to aircraft based on the traffic management program parameters. The delay assignment...
• Delay countdown timer (DCT)The display of the delay that must be absorbed by a flight prior to crossing a Meter Reference Element (MRE)...
• Delay indefinite (reason if known) expect further clearance (time)Used by ATC to inform a pilot when an accurate estimate of the delay time and the reason for the delay cannot...
• Departure centerThe ARTCC having jurisdiction for the airspace that generates a flight to the impacted airport.
• Departure clearance (DCL) applicationThe DCL application provides up to nine Selectable Fields for the tower controller to enter all other...
• Departure controlA function of an approach control facility providing air traffic control service for departing IFR and, under...
• Departure sequencing programA program designed to assist in achieving a specified interval over a common point for departures.
• Departure timeThe time an aircraft becomes airborne.
• Departure viewerA capability within the Traffic Flow Management System (TFMS) that provides combined displays for monitoring...
• Descend viaAn abbreviated ATC clearance that requires compliance with a published procedure lateral path and associated...
• Descent speed adjustmentsSpeed deceleration calculations made to determine an accurate VTA. These calculations start at the transition...
• Designated common traffic advisory frequency (CTAF) areaIn Alaska, in addition to being designated for the purpose of carrying out airport advisory practices while...
• Desired coursea. True- A predetermined desired course direction to be followed (measured in degrees from true north).
• Desired trackThe planned or intended track between two waypoints. It is measured in degrees from either magnetic or true...
• DETRESFA (distress phase) [ICAO]The code word used to designate an emergency phase wherein there is reasonable certainty that an aircraft and...
• Deviationa. A departure from a current clearance, such as an off course maneuver to avoid weather or turbulence.
• DH, see Decision height (DH)
• Digital targetA computer-generated symbol representing an aircraft's position, based on a primary return or radar beacon...
• Digital terminal automation system (DTAS)A system where digital radar and beacon data is presented on digital displays and the operational program...
• Digital-automatic terminal information service (D-ATIS)The service provides text messages to aircraft, airlines, and other users outside the standard reception...
• Digitized targetA computer-generated indication shown on an analog radar display resulting from a primary radar return or a...
• DirectStraight line flight between two navigational aids, fixes, points, or any combination thereof. When used by...
• Directly behindAn aircraft is considered to be operating directly behind when it is following the actual flight path of the...
• Discrete beacon code, see Discrete code
• Discrete codeAs used in the Air Traffic Control Radar Beacon System (ATCRBS), any one of the 4096 selectable Mode 3/A...
• Discrete frequencyA separate radio frequency for use in direct pilot-controller communications in air traffic control which...
• Displaced thresholdA threshold that is located at a point on the runway other than the designated beginning of the runway.
• Distance measuring equipment (DME)Equipment (airborne and ground) used to measure, in nautical miles, the slant range distance of an aircraft...
• DistressA condition of being threatened by serious and/or imminent danger and of requiring immediate assistance.
• Dive brakes, see Speed brakes
• Diverse vector areaIn a radar environment, that area in which a prescribed departure route is not required as the only suitable...
• Diversion (DVRSN)Flights that are required to land at other than their original destination for reasons beyond the control of...
• DME, see Distance measuring equipment (DME)
• DME fixA geographical position determined by reference to a navigational aid which provides distance and azimuth...
• DME separationSpacing of aircraft in terms of distances (nautical miles) determined by reference to distance measuring...
• DoD FLIPDepartment of Defense Flight Information Publications used for flight planning, en route, and terminal...
• Domestic airspaceAirspace which overlies the continental land mass of the United States plus Hawaii and U.S. possessions...
• Domestic noticeA special notice or notice containing graphics or plain language text pertaining to almost every aspect of...
• DownburstA strong downdraft which induces an outburst of damaging winds on or near the ground. Damaging winds, either...
• DownlinkCPDLC message sent from the flight deck to ATC.
• Downwind leg, see Traffic pattern
• DP, see Instrument departure procedure (DP)
• DRA, see Debris response area (DRA)
• Drag chuteA parachute device installed on certain aircraft which is deployed on landing roll to assist in deceleration...
• Drop zoneAny pre-determined area upon which parachutists or objects land after making an intentional parachute jump or...
• DSP, see Departure sequencing program
• DTAS, see Digital terminal automation system (DTAS)
• Due regardA phase of flight wherein an aircraft commander of a State-operated aircraft assumes responsibility to...
• Duty runway, see Runway in use/active runway/duty runway
• DVA, see Diverse vector area
• DVFR, see Defense visual flight rules
• DVFR flight planA flight plan filed for a VFR aircraft which intends to operate in airspace within which the ready...
• DVRSN, see Diversion (DVRSN)
• DynamicContinuous review, evaluation, and change to meet demands.
• Dynamic restrictionsThose restrictions imposed by the local facility on an “as needed” basis to manage unpredictable fluctuations...

52 of 1,122 terms in Aviation and air traffic control terminology (MLC-0104). Request the full dataset.