 The U.S. Federal Aviation Administration (FAA) introduced the generic term "TAWS" to encompass all terrain-avoidance systems that meet the relevant FAA standards, which include GPWS, EGPWS and any future system that might replace them.As of 2007, 5% of the world's commercial airlines still lacked a TAWS.A study by the International Air Transport Association examined 51 accidents and incidents and found that pilots did not adequately respond to a TAWS warning in 47% of cases.