Aeronautical Terms beginning with D

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 Sequencing Program

A program designed to assist in achieving a specified interval over a common point for departures.

Digital-Automatic Terminal Information Service (D-ATIS)

The service provides text messages to aircraft, airlines, and other users outside the standard reception range of conventional ATIS via landline and data link communications to the cockpit. Also, the service provides a computer-synthesized voice message that can be transmitted to all aircraft within range of existing transmitters. The Terminal Data Link System (TDLS) D-ATIS application uses weather inputs from local automated weather sources or manually entered meteorological data together with preprogrammed menus to provide standard information to users. Airports with D-ATIS capability are listed in the Airport/Facility Directory.

Diluter-demand oxygen system

An oxygen system that delivers oxygen mixed or diluted with air in order to maintain a constant oxygen partial pressure as the altitude changes.

Domestic Reduced Vertical Separation Minimum (DRVSM)

Additional flight levels between FL 290 and FL 410 to provide operational, traffic, and airspace efficiency.

Ducted-Fan Engine

An engine-propeller combination that has the propeller enclosed in a radial shroud. Enclosing the propeller improves the efficiency of the propeller.

Duty Runway

Runway In Use/Active Runway/Duty Runway.