Controlled flight into terrain (CFIT) is a crash in which a working aircraft, flown by a qualified crew, hits the ground, water or an obstacle without the crew realising they are in danger. The FAA’s definition stresses all three parts: a properly functioning aircraft, under control, flown into terrain “with no apparent awareness on the part of the crew”. Nothing broke. The crew did not know where the ground was.
What CFIT means: a working aircraft flown into the ground
CFIT is different from a loss of control, where the aircraft is no longer being flown as the crew intends. It is also different from a mechanical failure that forces an aircraft down. In a CFIT accident the engines, controls and instruments are all working. The aircraft goes where it is pointed, and it is pointed at the ground.
That is why the answer to CFIT has been warnings, not stronger aircraft. A crew that knows the ground is close will climb.
Why it happens
The official reports on CFIT accidents keep finding the same conditions:
- Darkness and no visual horizon. Eastern 401 crashed at night over the Everglades. American 965 crashed into mountains on a clear night with no moon.
- Attention on something else. The Eastern 401 crew were absorbed in a landing gear indicator light and did not notice the aircraft descending.
- Confusion about position. On American 965, the crew were confused about the approach and about how to identify the fixes on it.
- Approaches without vertical guidance. Korean Air 801 was flying a nonprecision approach, which gives the crew a course to follow but no electronic glide path down to the runway.
- Fatigue, and missing cross-checks. The NTSB found the Korean Air captain was fatigued and the other two crew members did not effectively monitor and cross-check him.
- Safety nets switched off or too late. At Guam, the FAA had deliberately inhibited the ground-based minimum safe altitude warning. On American 965, the basic ground proximity warning worked, but too late to clear the mountains.
In each case several of these lined up at once, which is the pattern the Swiss cheese model explains.
Three CFIT accidents
These events do not have pages on this site yet.
Eastern Air Lines Flight 401, the Everglades, 29 December 1972
An Eastern Lockheed L-1011 TriStar approaching Miami went around because the nose landing gear indicator did not show the gear locked down. The aircraft climbed to 2,000 feet and flew west from the airport while the three flight crew and a jump-seat occupant tried to sort out the problem. It descended without anyone noticing and crashed at 23:42 about 18 miles west-north-west of Miami International Airport. Of the 176 people on board, 94 passengers and 5 crew died in the crash, and two survivors died later.
The NTSB found that the probable cause was the crew’s failure to monitor the flight instruments during the final four minutes of flight, and to detect an unexpected descent soon enough to prevent impact with the ground. Preoccupation with a malfunction of the nose gear indicating system distracted them, and the descent went unnoticed.
American Airlines Flight 965, Cali, Colombia, 20 December 1995
A Boeing 757 on approach to Cali crashed into high terrain at about 21:42 local time. Of the 163 people on board, four survived. According to the FAA’s summary of the Colombian Aeronáutica Civil investigation, the investigators found the crew were confused during the approach and did not know how to identify the approach fixes properly. The FAA describes the accident as flight crew error involving navigation and crew resource management lapses. The aircraft had a ground proximity warning system, and it worked normally, but it did not warn the crew in time to avoid the mountains.
Korean Air Flight 801, Guam, 6 August 1997
A Boeing 747-300 on a nonprecision approach to Guam struck Nimitz Hill, about 3 miles south-west of the airport, at about 01:42 local time. Of the 254 people on board, 228 were killed. The NTSB (report AAR-00/01) found that the probable cause was the captain’s failure to adequately brief and fly the approach, and the first officer’s and flight engineer’s failure to effectively monitor and cross-check him. The captain’s fatigue and Korean Air’s inadequate crew training contributed. So did the FAA’s intentional inhibition of the minimum safe altitude warning system at Guam, and its failure to manage that system adequately.
What changed: GPWS, then terrain awareness
Ground proximity warning, 1974. Studies from the early 1970s found that many CFIT accidents could have been avoided with a warning device. In 1974, following those studies and NTSB recommendations, the FAA required airlines operating large turbine aircraft to install a ground proximity warning system (GPWS). In 1978 it extended the rule to smaller turbojets in commuter service.
Terrain awareness, 2000 rule. Cali showed the limit of the older systems: the GPWS worked, but the warning came too late. The FAA calls American 965 the catalyst for requiring terrain awareness and warning systems (TAWS), also known as enhanced GPWS. Its rule of 29 March 2000 says TAWS improves on GPWS with much earlier warnings, a forward-looking capability, and continued operation when the aircraft is configured to land. The FAA said it expected manufacturers to give at least 20 seconds of warning before a potential impact.
The rule, now 14 CFR 121.354 for airlines, set two dates:
- Turbine aircraft built after 29 March 2002 must have Class A TAWS, which includes a terrain display.
- Turbine aircraft built on or before that date had to be fitted with it by 29 March 2005.
The requirement also reached turbine aircraft with six or more passenger seats outside airline service. That followed NTSB recommendations after CFIT accidents to corporate jets that had not been required to carry GPWS.
How these alerts work in the cockpit, and their counterpart for mid-air collisions, are explained in TCAS and Terrain Warnings.
The record since
In the 2000 rule, the FAA wrote that there had been a reduction in the CFIT accident rate since 1974, when it first required GPWS on airliners. It added that some risk remained, in part because older generations of GPWS were less capable. That gap is what TAWS was meant to close. An FAA-commissioned study cited in the rule examined 44 accidents to turbine aircraft with six or more passenger seats flown outside airline rules. It estimated that GPWS could have prevented 33 of them and enhanced GPWS 42.
The investigations above are worth reading in full for how investigators separate what the crew knew from what the instruments showed. How to Read an Air Accident Final Report explains how the reports are laid out.
The three cases compared
| Flight | Aircraft | Date and place | Conditions | Warning system | Deaths | Investigating body |
|---|---|---|---|---|---|---|
| Eastern 401 | Lockheed L-1011 TriStar | 29 December 1972, Everglades, Florida | Night, over swamp | None required at the time | 99 in the crash, 2 later | NTSB |
| American 965 | Boeing 757-223 | 20 December 1995, near Cali, Colombia | Night, no moon, mountains | GPWS worked but warned too late | 159 of 163 | Aeronáutica Civil (Colombia) |
| Korean Air 801 | Boeing 747-300 | 6 August 1997, Nimitz Hill, Guam | Night, nonprecision approach | Ground-based minimum safe altitude warning inhibited by the FAA | 228 of 254 | NTSB |
Sources
- Federal Aviation Administration: Terrain Awareness and Warning System, final rule, 65 FR 16736, 29 March 2000 (background on CFIT and GPWS; 14 CFR 121.354)
- US Code of Federal Regulations (eCFR): 14 CFR 121.354, Terrain awareness and warning system
- National Transportation Safety Board: Aircraft Accident Report NTSB-AAR-73-14, Eastern Air Lines, Inc., L-1011, N310EA, Miami, Florida, December 29, 1972
- Federal Aviation Administration: Lessons Learned: American Airlines Flight 965, Boeing 757-223, N651AA, Cali, Colombia, December 20, 1995 (summary of the Aeronáutica Civil investigation)
- National Transportation Safety Board: Aircraft Accident Report NTSB/AAR-00/01, Controlled Flight Into Terrain, Korean Air Flight 801, Boeing 747-300, HL7468, Nimitz Hill, Guam, August 6, 1997
Last checked 31 October 2026.