LAX97LA176 · Hughes 369D
Hughes 369D · Accident: total loss of engine power (mechanical failure) en route
From MANO POINT, HI to Waimea Kohala Airport (MUE)
Event
- NTSB case
- LAX97LA176
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 2 · all aircraft and ground
- Ground fatalities
- 0
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Hughes 369D
- Aircraft type
- Hughes 369
- Category
- Helicopter
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N5105N
- Operator
- Kaohukaukuahiwi K. Sproat · private individual
- Onboard fatalities
- Unknown
- Route
- From MANO POINT, HITo Waimea Kohala Airport (MUE), WAIMEA-KOHALA, HI
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- En route · cruise
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Total loss of engine power (mechanical failure)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Destroyed
Cause areas
- Company maintenance personnel › Maintenance, annual inspection, inadequate
- Compressor assembly, stator vane › Eroded
- Compressor assembly, stator vane › Fatigue
- Pilot in command › Aircraft weight and balance, improper
- Pilot in command › Flare, not attained
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The helicopter was cruising at low level when the engine failed. The pilot turned toward a landing area and entered an autorotation with a quartering tailwind. During the autorotation, the helicopter continued to descend, remaining in a nose low attitude, until striking the ground. Impact occurred on up sloping terrain, and the helicopter was damaged. A computation of the weight and balance revealed the helicopter's moment arm exceeded the forward CG limit by about one inch, and limited aft cyclic control. An examination of the engine revealed that a stator vane had failed due to excessive erosion and fatigue cracking. The condition had not been detected during a compressor case erosion inspection, 60 flight hours before the accident.
Probable cause
erosion of second stage stator vanes, inadequate maintenance inspection for the erosion, and subsequent fatigue failure of a stator vane, which resulted in loss of engine power and a forced landing on mountainous/hilly terrain. Also causal was: the pilot's loading of the aircraft in such a manner that exceeded the forward CG limit, which resulted in his failure (or inability) to properly flare the helicopter during a forced autorotation and landing. The rising terrain and tailwind condition for landing were related factors.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX97LA176
- Event ID
- 20001208X07947
- Case number
- LAX97LA176
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: local date, investigation status. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 1997-05-11.
- API snapshot SHA-256: 629646fdfa9aa73176e4a5c6cea09809eea48c66040b12ca3dc8e25a41d45528; retrieved 2026-09-20T22:58:03.670Z.