TM 1-1510-224-10 DCU Digital computer unit DD Differential doppler DEG Degrees DEL Delete DES TRK Desired track DEV Deviation DFT ANG Drift angle DG Directional gyro DH Decision height DIAG Diagnostic DIR Direct DISP Dispenser DIST Distance DIV Diverse DL Data link DME Distance measuring equip- ment DN Down DOP Dilution of precision DOY Day of the year DSCRM Discriminate DTRK Desired track DTS Data transfer system DUR Duration E East EADI Electronic attitude director indicator ECCM Electronic counter- countermeasure EEPROM Electrically   erasable/ programmable read only memory EFIS Electronic flight instrument system EHSI Electronic horizontal situation indicator ELEV Elevation ELT Emergency locator transmitter EMER Emergency ENG Engage EPE Estimated position error ERF Electronic remote fill ESV Error state vector ET Elapsed time EX LOC Expanded localizer EXT External FAA Federal aviation administration FC Frequency/code FCC Flight control computer FD, F/D Flight director FH Frequency hopping FH-M Frequency hopping-master FLIP Flight information publications FLT Flight FM Frequency modulation FOD Foreign object damage FOM Figure of merit FP Flight plan FPLN Flight plan FR, FRM From FREQ Frequency FS Fuselage station FT Foot or feet FT-LB Foot-pounds FT/MIN Feet per minute G Glideslope B-6