A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Decision altitude/height - DA/H - A specified altitude or height, in the precision approach at which a missed approach must be initiated if the required visual reference to continue the approach has not been established.

.Density altitude - is the altitude corrected for non-ISA International Standard Atmosphere atmospheric conditions

Departure control - A function of an approach control facility providing air traffic control service for departing IFR and, under certain conditions, VFR aircraft.

dependent parallel approaches - simultaneous approaches to parallel instrument runways where radar separation minima between aircraft using adjacent ILS are prescribed.

Descent profile - Continuous Descent Approach (CDA)

Also known as Optimized Profile Descent (OPD), this is a method by which aircraft approach airports prior to landing. It is designed to reduce fuel consumption and noise compared to other conventional descents. Instead of approaching an airport in a stairstep fashion, throttling down and requesting permission to descend to each new (lower) altitude, CDA allows for a smooth, constant-angle descent to landing.

A continuous descent approach starts from the top of descent, i.e. at cruise altitude, and allows the aircraft flying its individual optimal vertical profile down to runway threshold. Some airports apply constraints to this individual optimal profile.

Direct track/route - DT - A requested route published on en-route or area chart to assist pilots who have previous knowledge of acceptance

of these routs by ATC. Use of direct route may require prior ATC approval and may not provide ATC or advisory services, or be acceptable

in flight plans.

Displaced threshold - A 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 from the DME navigational aid.

Duplex – two-way communication with capability to speak and to listen at the same time (for example: telephone)

Double channel duplex – simplex using 2 frequency channels, one each directionאינטרקום או טלפון -