Air Transport World

GPWS, y-e-s: unsung, unloved and underutilized, the Ground Proximity Warning System continues to prove its worth day in and day out.

The ground proximity warning system (GPWS) is the ugly duckling of modern aviation-safety technology. Rushed into service by order of FAA following the 1974 crash of a TWA 727 near Washington Dulles Airport, the GPWS labored under a reputation for unreliability long after technological advances turned succeeding versions into swans.

Today, with sexy high-tech devices such as the Traffic Alert and Collision Avoidance System (TCAS) and wind-shear-detection systems entering the cockpits, it is worth reflecting on the importance of the oft-abused GPWS.

Talk to almost any independent safety expert and he or she will tell you that sure, TCAS and wind-shear detection are wonderful inventions but if only we could get people to pay as much attention to their ground-proximity warning systems....

A lesser reward

Furthermore, advancements in TCAS and wind-shear training are unlikely to bring as large a reward-in terms of lives saved-as would an equally dedicated effort on behalf of the GPWS. Consider that the last wind-shear-related crash in the U.S. happened in 1985, well before FAA mandated the introduction of wind-shear-detection systems. The last midair collision involving a commercial jet transport occurred in 1986, before the first production TCAS had been installed in any aircraft.

By contrast, controlled flight into terrain (CFIT), the phenomenon that GPWS was designed to help prevent, continues to bedevil airlines, be it a Korean Air DC-10 in Libya in 1989, an indian Airlines A320 in India in 1990 or an Alitalia MD-80 in Switzerland in the same year, to name but three of the most well-publicized accidents. …

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