The performance of warning systems in avoiding controlled-flight-into-terrain (CFIT) accidents.

This paper examines the performance of two systems to prevent controlled-flight-into-terrain (CFIT) accidents, including their development and preimplementation issues and attitudes. The airborne version, the Ground Proximity Warning System (GPWS), was required for certain large turbine-powered airplanes. The ground-base system, the Minimum Safe Altitude Warning (MSAW) is a feature of the ARTS-3 system. Accident data from the National Transportation Safety Board (NTSB) and reports from the Aviation Safety Reporting System (ASRS) were used in assessing performance. It is concluded that these systems have dramatically reduced accidents. Although false and nuisance alarms continue, no evidence suggests that they have caused any accident. The tenacity of the alarms--especially the GPWS--as well as appropriate triggering criteria seem to be basic to their success.