Ground Proximity Warning System - Effects and Statistics

Effects and Statistics

Prior to the development of GPWS, large passenger aircraft were involved in 3.5 fatal CFIT accidents per year, falling to 2 per year in the mid-1970s. Since 1974, when the U.S. Federal Aviation Administration made it a requirement for large aircraft to carry such equipment, there has not been a single passenger fatality in a CFIT crash by a large jet in U.S. airspace.

After 1974, there were still some CFIT accidents which GPWS was unable to help prevent, due to the blind spot of those early GPWS systems. More advanced systems were developed.

Older TAWS systems, or deactivation of the EGPWS system, or ignoring its warnings when airport is not in its database still leave aircraft vulnerable to possible CFIT incidents. In April 2010, a Polish Air Force Tupolev Tu-154M aircraft crashed near Smolensk, Russia, in a possible CFIT accident killing all passengers and crew. The aircraft was equipped with TAWS made by Universal Avionics Systems of Tucson. According to the Russian Interstate Aviation Committee TAWS was turned on. However, the airport where the aircraft was going to land (Smolensk (XUBS)) is not in the TAWS database. In January 2008 a Polish Air Force Casa C-295M crashed in a CFIT accident near Mirosławiec, Poland, despite being equipped with EGPWS; the EGPWS warning sounds had been disabled, and the pilot-in-command was not properly trained with EGPWS.