Demonstration of how the Auto GCAS works
The Automatic Ground Collision Avoidance System is designed to prevent Controlled Flight Into Terrain mishaps by executing an automatic recovery maneuver when terrain impact is imminent. The system predicts CFIT conditions by means of a continuous comparison between a trajectory prediction and a terrain profile that is generated from onboard terrain elevation data. At the instant the predicted trajectory touches the terrain profile; the automatic recovery is executed by the Auto GCAS autopilot. The automatic recovery consists of an abrupt roll-to-upright and a nominal 5-g pull until terrain clearance is assured. The Auto GCAS recovery maneuver can be terminated at any time by the pilot. (U.S. Air Force graphic by Jet Fabara)