Controlled Flight Into Terrain.

Controlled-Flight-Into-Terrain (CFIT) incidents represent the single greatest risk to aircraft, crews and passengers. CFIT incidents have been the leading cause of fatalities in large commercial jet accidents.

CFIT occurs when an airworthy aircraft, under the control of the flight crew, is flown unintentionally into terrain, obstacles, or water, usually with no prior awareness by the crew. This type of accident can occur during most phases of flight, but CFIT is more common during the approach-and-landing phases, which typically comprise only 16 percent of the average flight duration of a large commercial jet.