DA
Drift Angle
DA/H
Decision Altitude / Height (rel. to THR) See Instrument Landing System
DER
Departure End of Runway / Designated Engineering Representative
DFDR
Digital Flight Data Recorder
DG
Directional Gyroscope
DG
Directional Gyro
DGCA
Directorate General of Civil Aviation (various countries)
DGPS
Differential Global Positioning System
DGR
Dangerous Goods Regulations
DH
Decision Height
DLR
German Aerospace Center / Deutsches Zentrum für Luft- und Raumfahrt e.V.
DME
Distance Measuring Equipment
DME
Distance Measuring Equipment
DNC
Direct Noise Canceling
DOT
US Department of Transportation (also refers to Dept of Transport in many countries)
DP
Departure Procedures
DR
Dead reckoning
DSP
Digital Signal Processing
DUAT
Direct User Access Terminal