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Gerardin Hughes 369HS accident

5 May 1991 · KEANAE, HI, United States

Hughes 369HS · Accident: loss of engine power en route

From Kahului International Airport (OGG) to Kahului International Airport (OGG)

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Event

NTSB case
LAX91LA198
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
0 · 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
Charter & commuter
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 369HS

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
N9219F
Operator
Gerardin
Onboard fatalities
Unknown
Route
From Kahului International Airport (OGG), Kahului, HITo Kahului International Airport (OGG), Kahului, 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 135: Air Taxi & Commuter
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
Loss of engine power
Also codedOther events the NTSB coded in the sequence, such as a wire strike after a loss of power. Flight Findings uses them for its kinds of event. Glossary
Tree(s)
DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
Substantial

Cause areas

  • Turboshaft engine, gas generator turbine shaft › Fatigue

Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.

NTSB narrative

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.

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.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record LAX91LA198
Event ID
20001212X17032
Case number
LAX91LA198
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: investigation status. Values present in the bulk record are kept.
  • The date is the local date, which is the same as the UTC date the NTSB stores.
  • API snapshot SHA-256: 27ad947ca808de53550234a3b4ce7fa3a43649c6c0d6351d3ef02c1cfeaa39de; retrieved 2026-09-18T18:55:11.049Z.