noun
ground proximity warning system; GPWS
Aviation safety system that alerts pilots when the aircraft is in danger of flying into the ground or an obstacle.
対地接近警報装置が作動し、機長は直ちに機首を上げた。
The ground proximity warning system activated, and the captain immediately pulled up the nose.
Compound of 対地 (たいち, 'relative to the ground'), 接近 (せっきん, 'approach'), 警報 (けいほう, 'warning'), and 装置 (そうち, 'device').