(See EXPECT FURTHER CLEARANCE (TIME).)
DELAY TIME- The amount of time that the arrival must lose to cross the meter fix at the assigned meter fix time. This is the difference between ACLT and VTA.
DEPARTURE CENTER-The ARTCC having jurisdiction for the airspace that generates a flight to the impacted airport.
DEPARTURE CONTROL- A function of an approach control facility providing air traffic control service for departing IFR and, under certain conditions, VFR aircraft.
(See APPROACH CONTROL FACILITY.)
(Refer to AIM.)
DEPARTURE SEQUENCING PROGRAM-A program designed to assist in achieving a specified interval over a common point for departures.
DEPARTURE TIME- The time an aircraft becomes airborne.
DESCENT SPEED ADJUSTMENTS- Speed decel-eration calculations made to determine an accurate VTA. These calculations start at the transition point and use arrival speed segments to the vertex.
DESIRED COURSE-
a..
True- A predetermined desired course direction to be followed (measured in degrees from true north).
b.
Magnetic- A predetermined desired course direction to be followed (measured in degrees from local magnetic north).
DESIRED TRACK- The planned or intended track between two waypoints. It is measured in degrees from either magnetic or true north. The instantaneous angle may change from point to point along the great circle track between waypoints.
DETRESFA (DISTRESS PHASE) [ICAO]- The code word used to designate an emergency phase wherein there is reasonable certainty that an aircraft and its occupants are threatened by grave and imminent danger or require immediate assistance.
DEVIATIONS-
a..
A departure from a current clearance, such as an off course maneuver to avoid weather or turbulence.
b..
Where specifically authorized in the CFRs and requested by the pilot, ATC may permit pilots to deviate from certain regulations.
(Refer to AIM.)
DF-
(See DIRECTION FINDER.)
DF APPROACH PROCEDURE- Used under emergency conditions where another instrument approach procedure cannot be executed. DF guidance for an instrument approach is given by ATC facilities with DF capability.
(See DF GUIDANCE.)
(See DIRECTION FINDER.)
(Refer to AIM.)
DF FIX- The geographical location of an aircraft obtained by one or more direction finders.
(See DIRECTION FINDER.)
DF GUIDANCE- Headings provided to aircraft by facilities equipped with direction finding equipment. These headings, if followed, will lead the aircraft to a predetermined point such as the DF station or an airport. DF guidance is given to aircraft in distress or to other aircraft which request the service. Practice DF guidance is provided when workload permits.
(See DIRECTION FINDER.)
(See DF FIX.)
(Refer to AIM.)
DF STEER-
(See DF GUIDANCE.)
DH-
(See DECISION HEIGHT.)
DH [ICAO]-
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