Pilot/Controller Glossary

4/3/14

PCG D−2

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.

DESCEND VIA– An abbreviated ATC clearance that

requires compliance with a published  procedure

lateral path and associated speed restrictions and

provides a pilot-discretion descent to comply with

published altitude restrictions.

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.

DH−

(See DECISION HEIGHT.)

DH [ICAO]−

(See ICAO Term DECISION ALTITUDE/

DECISION HEIGHT.)

DIGITAL-AUTOMATIC TERMINAL INFORMA-

TION 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.

DIGITAL TARGET− A computer−generated symbol

representing an aircraft’s position, based on a primary

return or radar beacon reply, shown on a digital

display.

DIGITAL TERMINAL AUTOMATION SYSTEM

(DTAS)− A system where digital radar and beacon

data is presented on digital displays and the

operational program monitors the system perfor-

mance on a real−time basis.

DIGITIZED TARGET− A computer−generated

indication shown on an analog radar display resulting

from a primary radar return or a radar beacon reply.

DIRECT

− Straight line flight between two naviga-

tional aids, fixes, points, or any combination thereof.

When used by pilots in describing off-airway routes,

points defining direct route segments become

compulsory reporting points unless the aircraft is

under radar contact.

DIRECT ALTITUDE AND IDENTITY READ-

OUT− The DAIR System is a modification to the

AN/TPX-42 Interrogator System. The Navy has two

adaptations of the DAIR System-Carrier Air Traffic

Control Direct Altitude and Identification Readout

System for Aircraft Carriers and Radar Air Traffic

Control Facility Direct Altitude and Identity Readout

System for land-based terminal operations. The

DAIR detects, tracks, and predicts secondary radar

aircraft targets. Targets are displayed by means of

computer-generated symbols and alphanumeric

characters depicting flight identification, altitude,

ground speed, and flight plan data. The DAIR System

is capable of interfacing with ARTCCs.

DIRECTLY BEHIND− An aircraft is considered to

be operating directly behind when it is following the

actual flight path of the lead aircraft over the surface