Investigation Summary
Flight 514 was originally destined for Washington National Airport but diverted to Dulles due to high crosswinds. While being vectored for the VOR/DME approach to Runway 12, the controller cleared the flight for the approach. The crew interpreted this clearance as an authorization to descend immediately to the minimum approach altitude of 1,800 feet. However, they were still 25 miles from the airport in an area where the minimum obstacle clearance altitude was significantly higher. The aircraft struck the west slope of Mount Weather at 1,670 feet MSL in heavy clouds and turbulence.
Final Conclusions
The NTSB determined the probable cause was the crew's decision to descend to 1,800 feet before the aircraft had reached the approach segment where that altitude was safe. This was driven by a lack of clarity in Air Traffic Control procedures and terminology regarding 'cleared for the approach' when an aircraft is off a published route.
Video Analysis
The Confusion That Killed 92 People | TWA Flight 514 — An analysis of the 1974 crash of TWA Flight 514 and how a misunderstanding of ATC terminology led to a fatal descent into Mount Weather.
Watch on YouTube ↗If playback is blocked, the owner has disabled embedding — use the link above.
Systems & Failure Modes
VOR/DME
A radio navigation system providing both bearing and distance, used by the crew to track the approach path.
ATC Terminology
The standardized language used between pilots and controllers; at the time, 'cleared for the approach' was dangerously ambiguous.
Interesting Facts
- 01The accident occurred during a period of high winds and low visibility caused by a winter storm.
- 02A United Airlines flight had narrowly avoided the same mountain just weeks prior under similar circumstances.
- 03The crew and the controller had different understandings of what 'cleared for the approach' meant while being vectored.
- 04All 92 people on board were killed instantly upon impact.
Safety Actions & Advisories
GPWS Mandate
Source ↗The crash led the FAA to mandate Ground Proximity Warning Systems (GPWS) for all commercial airliners.
Standardized Terminology
Source ↗ATC procedures were changed to require controllers to specify altitudes until an aircraft is established on a published segment of an approach.
ASRS Establishment
Source ↗The accident contributed to the creation of the Aviation Safety Reporting System (ASRS) to allow pilots to report 'near misses' without fear of penalty.