Listen to the sound clip Caution terrain. from Boeing EGPWS GPWS Callouts: Caution terrain. Caution terrain. This sound is from Boeing EGPWS GPWS Callouts Boeing EGPWS (Enhanced Ground Proximity Warning System) GPWS (Ground Proximity Warning System) callout are audio warnings that alert pilots to potential hazards in the aircraft's flight path. The callout are designed to be clear… Go to the full soundboardwith more sound clips Search