ABSTRACT
The Enhanced Ground Proximity Warning System (EGPWS) is one of the newest systems becoming standard on all military and civilian aircraft. Its purpose is to help provide situational awareness to terrain and to provide predictive alerts for flight into terrain. The current state of the aircraft is indicated by its position relative to ground and surrounding terrain, attitude, motion vector, accelerations vector, configuration, current navigation data, and phase of flight. Once displayble terrain elevation database became a technical and economic reality, the obvious next step was to use the data to look ahead of the aircraft path and predict terrain conflict well before it happened, rather than waiting for the downward-looking sensors. The enhanced modes provide terrain and obstacle awareness beyond the normal sensor-derived capabilities of the standard GPWS. Voice alerts for the cautionary alert are “Caution, Terrain” or “Terrain Ahead.” For the warnings on turboprop and turbojet aircraft, the warning aural is “Terrain Terrain Pullup” or “Terrain Ahead Pullup,”.
