# NTSB LAX85FA136: Hughes 369D, N369LA, Hilo, HI, February 6, 1985

- Type: NTSB accident investigation
- Classification: Accident · Fatal · Field investigation · Final report
- Date: February 5, 1985, 15:50 local (Feb 6, 1985, 01:50 UTC)
- Place: Hilo, HI
- Coordinates: 19.689336, -155.080215 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=19.6893&lon=-155.0802&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Fatal
- Injuries: 1 fatal
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 24469
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX85FA136
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/24469/pdf
- Page: https://openairdocs.org/ntsb/LAX85FA136

## Sequence of events

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

- Airframe/component/system failure/malfunction, cruise - normal
  - maintenance,modification - improper, other maintenance personnel (cause)
  - maintenance,inspection - inadequate (contributing factor)
  - fuselage,fairing - distorted (cause)
  - aircraft preflight - inadequate, pilot in command (cause)
  - rotor drive system,engine to transmission drive - worn (cause)
  - rotor drive system,engine to transmission drive - failure,total (cause)
  - engine assembly,mount - failure,total (cause)
- Forced landing, descent - emergency
  - autorotation - performed, pilot in command
- In flight collision with object, landing - flare/touchdown
  - terrain condition - none suitable (contributing factor)
  - object - tree(s) (contributing factor)
- Roll over, landing - flare/touchdown
  - terrain condition - high vegetation (contributing factor)
  - terrain condition - mountainous/hilly (contributing factor)

## Analysis

A SEARCH WAS INITIATED WHEN THE HELICOPTER DID NOT ARRIVE. IT WAS FND 2 DAYS LATER WHERE IT CRASHED DRG AN AUTOROTATION IN A RAIN FOREST. DRG THE FLARE/TOUCHDOWN, VEGETATION HAD CAUGHT ON A TUNDRA PAD ON THE L SKID & THE ACFT ROLLED OVER. AN EXAM REVEALED THE LWR BENDIX COUPLING ON THE ENG-TO-TRANSMISSION DRIVE SHAFT, PN 369A4410, & THE UPPER R ENG MOUNT, PN 369H8017, HAD FAILED. UNAPPROVED MOD/REPAIRS HAD BEEN MADE TO BOTH THE DRIVE SHAFT & OVERLYING COVER PANEL. A STEEL REINFORCING ROD HAD BEEN INSTALLED INSIDE THE COVER PANEL. DUE TO PRESSURE OF CARGO (LARGE WTR BUCKET), THE STEEL ROD HAD BEEN FORCED ONTO THE DRIVE SHAFT. THERE WAS EVIDENCE OF ANGULAR MISALIGNMENT & LATER FAILURE OF THE DRIVE SHAFT. A METALLURGICAL EXAM OF THE ENG MOUNT REVEALED LOW CYCLIC FATIGUE IN THE THREADED ROD AREA OF THE ADJUSTING SCREW. THE FRACTURE AREA OF THE DRIVE SHAFT WAS TOO BADLY DAMAGED TO DETERMINE THE MODE OF FAILURE. ACFT PREV OPERD IN CANADA, REG C-GVTJ. ANNUAL INSPN & U.S. AIRWORTHINESS CERTIFICATE ISSUED DESPITE UNAPPROVED MOD. DATE OF MOD UNKNOWN.

## Aircraft

- Registration: [N369LA](https://openairdocs.org/deregistered/N369LA-1988-04-06), registration cancelled 1988-04-06, S/N 1260036D (OpenAirDocs)
- Reported make and model: HUGHES 369D
- Registry model: [Hughes Helicopters HUGHES 369D](https://openairdocs.org/model/hughes-helicopters-hughes-369d) (registry code 4470706) (OpenAirDocs)
- Category: Helicopter
- Serial number: 1260036D
- Airframe hours: 2165
- Engines: ALLISON 250-C20B 375 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Positioning, Part 91
- Registered owner: Kenai Helicopters
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, October 9, 1984, 101 hours before
- Departed: OGG, KAHULUI, HI
- Destination: VOLCANO NATL PK, HI

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 41; private, commercial; airplane ratings: multi-engine land, single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: left; toxicology performed; flight hours: 7,500 total, 500 in this make and model, 7,300 as pilot in command, 75 in the last 90 days, 30 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 120° at 9 knots
- Visibility: 15 statute miles
- Lowest ceiling: 24,000 ft broken
- Temperature: 79 °F, dew point 63 °F
- Altimeter: 29.00 inHg
- Observed at: ITO, 15 nm away

## 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 19850205063719A](https://openairdocs.org/incident/19850205063719A), Feb 5, 1985: Hughes 369D, Hilo, HI, Substantial damage. Roll over after tree strike during autorotation. Engine mount came losse, bendix coupling rubbed nonstandard brace.

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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