# NTSB LAX91LA198: Hughes 369HS, N9219F, Keanae, HI, May 5, 1991

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: May 5, 1991, 11:29 local (21:29 UTC)
- Place: Keanae, HI
- Coordinates: 20.870691, -156.45021 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=20.8707&lon=-156.4502&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 3 minor, 2 uninjured
- Status: Completed, report July 14, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 27194
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX91LA198
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/27194/pdf
- Page: https://openairdocs.org/ntsb/LAX91LA198

## Probable cause

THE TOTAL FAILURE IN FATIGUE OF THE HELICOPTER'S SPUR ADAPTER GEARSHAFT. A CONTRIBUTING FACTOR WAS RELATED TO THE LACK OF A SUITABLE EMERGENCY LANDING SITE.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Loss of engine power, cruise
  - turboshaft engine,gas generator turbine shaft - fatigue (cause)
  - turboshaft engine,gas generator turbine shaft - failure,total
- Forced landing, descent - emergency
  - terrain condition - none suitable (contributing factor)
- In flight collision with object, landing - flare/touchdown
  - object - tree(s)
- Roll over, landing - flare/touchdown

## Analysis

DURING AN AIR TAXI SIGHTSEEING FLIGHT THE PILOT EXPERIENCED A SUDDEN TOTAL LOSS OF ALL ENGINE POWER.  THE PILOT MADE A FORCED LANDING AND COLLIDED WITH TREES.  EXAM OF THE HELICOPTER'S ENGINE REVEALED THE FORWARD SPLINES ON THE SPUR ADAPTER GEARSHAFT HAD FAILED IN FATIGUE WHICH RESULTED IN THE SAG BEING DISCONNECTED FORM THE DRIVE SYSTEM. METALLURGICAL EXAM OF THE FAILED SAG REVEALED IT CONFORMED TO ITS MANUFACTURER'S DESIGN SPECIFICATIONS.  THE COMPRESSOR, AND THE SAG, WERE SUBJECT TO AN OVERHAUL 826.8 OPERATIONAL HOURS PRIOR TO THE ACCIDENT.

## Aircraft

- Registration: [N9219F](https://openairdocs.org/deregistered/N9219F-2013-05-22), registration cancelled 2013-05-22, S/N 940638S, built 1974 (OpenAirDocs)
- Reported make and model: HUGHES 369HS
- Registry model: [Hughes 369HS](https://openairdocs.org/model/hughes-369hs) (registry code 4470728) (OpenAirDocs)
- Registry engine: [Allison 250 SER 400HP](https://openairdocs.org/engine/allison-250-ser-400hp) (registry code 03013, turbo-shaft) (OpenAirDocs)
- Category: Helicopter
- Serial number: 940638S
- Engines: ALLISON 250-C20 400 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Part 135
- Operator: Gerardin Corp., doing business as Alex Air
- Last inspection: Unknown, January 2, 2000
- Departed: OGG, KAHULUI, HI
- Destination: OGG, KAHULUI, HI
- Flight plan: Company VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 38; flight instructor, commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 4,200 total, 380 in this make and model, 4,000 as pilot in command, 82 in the last 90 days, 68 in the last 30 days, 5 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 45° at 10 knots, gusting 15
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: 79 °F

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 19910505014259A](https://openairdocs.org/incident/19910505014259A), May 5, 1991: Hughes 369HS, Keanae, HI, Substantial damage. Lost engine power. Autorotated into trees. Spur adapter gearshaft splines failed. Improper compressor bolt loose.

## Other investigations on N9219F (2)

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

- [NTSB LAX90LA162](https://openairdocs.org/ntsb/LAX90LA162), May 4, 1990: Hughes 369C (N9219F), Kahului, HI, substantial damage. Probable cause: THE PILOTS FAILURE TO ENSURE THAT ADEQUATE ROOM EXISTED TO POSITION THE HELICOPTER ON THE LANDING PLATFORM. CONTRIBUTING TO THE ACCIDENT WAS THE FAILURE OF GROUND PERSONNEL TO ENSURE THAT HAZARDS TO…
- [NTSB SEA80FYM17](https://openairdocs.org/ntsb/SEA80FYM17), Feb 21, 1980: Hughes 369HS (N9219F), Siletz, OR, substantial damage

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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