Beginning in the early 1970s, a number of studies examined the occurrence of CFIT accidents.[3] Findings from these studies indicated that many such accidents could have been avoided if a warning device called a ground proximity warning system (GPWS) had been used. As a result of these studies and recommendations from the U.S. National Transportation Safety Board (NTSB), in 1974 the FAA required all large turbine and turbojet airplanes to install TSO-approved GPWS equipment.[3][4]
The ICAO recommended the installation of GPWS in 1979.[5]
C. Donald Bateman, a Canadian-born engineer, developed and is credited with the invention of GPWS.[6]
In March 2000, the U.S. FAA amended operating rules to require that all U.S. registered turbine-powered airplanes with six or more passenger seats (exclusive of pilot and copilot seating) be equipped with an FAA-approved TAWS.[3] The mandate affects aircraft manufactured after March 29, 2002.[7]