Adaptation of a Ground Proximity Warning System for Rotorcraft

Ground Proximity Warning Systems have experienced considerable success as a safety back-up device for fixed wing aircraft applications. Transferring this concept to a Rotorcraft, however, requires compensation for a type of aircraft that is intentionally flown at low altitudes, relatively slow airspeeds, and in most cases provides no definitive cues as it transitions to a landing or hovering state. The Naval Air System Command has chosen a system for selected helicopters in the Navy and Marine Corps inventory which has shown considerable promise during developmental and operational testing. The system incorporates a predictive warning algorithm which issues warnings based on the dynamic state of the aircraft rather than fixed altitudes alone. Other available features include a pilot selectable altitude warning, as well as warnings for excessive bank angle, gear-up landing, tailstrike, descent below ILS glideslope, and altitude loss immediately after takeoff.