NTSB CAROL · Event
Event LAX91LA154
Aircraft involved
Probable cause & findings
THE FAILURE OF THE PILOT TO MAINTAIN ADEQUATE ALTITUDE TO CLEAR MOUNTAINOUS TERRAIN. CONTRIBUTING TO THE ACCIDENT WAS PILOT FATIGUE DUE TO A LENGTHY CROSS COUNTRY FLIGHT.
Factual narrative
THE CERTIFICATED PRIVATE PILOT WAS ON A CROSS COUNTRY FLIGHT THAT BEGAN AT ABOUT 0830 HOURS AND WAS PLANNED TO COVER ABOUT 1,300 NAUTICAL MILES. THE PILOT DEPARTED HIS LAST FUEL STOP AT ABOUT 2000 HOURS WHERE A WITNESS REPORTED THAT THE PILOT APPEARED FATIGUED. THE ROUTE OF FLIGHT WAS OVER HIGH MOUNTAINOUS TERRAIN THAT HAD A MINIMUM FLIGHT ELEVATION OF 13,500 FEET. AN EMERGENCY LOCATOR TRANSMITTER SIGNAL WAS RECEIVED AT 0024 HOURS, LOCATED 105 MILES WEST OF THE LAST DEPARTURE AIRPORT. THE AIRPLANE WAS LOCATED BY SEARCH PERSONNEL AT 11,000 FEET AND HAD IMPACTED A MOUNTAIN SIDE IN A REMOTE AREA OF DEEP SNOW. AT THE ACCIDENT LOCATION, THE AIRPLANE WAS ABOUT 1,000 FEET BELOW THE MOUNTAIN RIDGE LINE. THE TIME AND LOCATION OF THE ACCIDENT PLACED THE AIRPLANE IN AN AREA THAT DID NOT HAVE ANY GROUND OR MOON ILLUMINATION. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12
Verbatim from NTSB's published report. Source file
NTSB_1991_LAX91LA154.txt.
Findings + structured fields enriched from FAA avall.mdb.
Full investigation docket on
data.ntsb.gov ↗.
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Related research
What the literature says.
Academic papers and agency reports matching this event's aircraft type or causal vocabulary (pilot fatigue). Sourced from NASA NTRS, NTSB Safety Studies, FAA CAMI, AOPA Air Safety Institute, Embry-Riddle Scholarly Commons, arXiv, and the Semantic Scholar academic graph.
- SKYbrary (Eurocontrol) 2023 · SKYbrary article
Pilot Fatigue — SKYbrary Knowledge Base
SKYbrary pilot fatigue review — circadian biology, biomathematical models (SAFE/FAID), commuting impacts, regulatory frameworks (FAR 117 + EU 83/2014).
- NASA NTRS 2023 · Presentation
Nasa Pilot Fatigue Research: Past, Present & Future
Pilot fatigue research at NASA Ames has a long history, initiated by a Congressional request to investigate the magnitude of fatigue, sleep loss and circadian disruption in flight operations, and how …
- FAA CAMI 2022 · CAMI technical report
Pilot Fatigue and Sleep Patterns in Long-Range and Ultra-Long-Range Operations
Field study of crew sleep and alertness during ultra-long-range commercial operations. Combines actigraphy, sleep diaries, and PVT-B reaction tests.
- NASA NTRS 2019 · Technical Memorandum (TM)
San Francisco Bar Pilot Fatigue Study
The purpose of this study was to evaluate the extent of fatigue among San Francisco Bar Pilots (Maritime Pilots) and its potential impact on safety, and to make recommendations concerning how the risk…
- NASA NTRS 2019 · Conference Proceedings
Pilot Fatigue and Circadian Desynchronosis
Pilot fatigue and circadian desynchronosis, its significance to air transport safety, and research approaches, were examined.
- Embry-Riddle Scholarly Commons 2024 · Conference paper
Benefits associated with improving fatigue regulations for cargo pilots
This study investigated the potential business benefits of improving fatigue regulations for cargo pilots in Brazil. The research objectives were to compare fatigue levels between cargo and passenger …
Browse the full corpus — academia portal ↗