# NTSB DEN83FA215: Hughes 369D, N8667F, Woodruff, UT, September 12, 1983

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Field investigation · Final report
- Date: September 12, 1983, 10:20 local (16:20 UTC)
- Place: Woodruff, UT
- Coordinates: 41.470153, -111.229248 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=41.4702&lon=-111.2292&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 16001
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN83FA215
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/16001/pdf
- Page: https://openairdocs.org/ntsb/DEN83FA215

## Sequence of events

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

- Airframe/component/system failure/malfunction, hover
  - rotor drive system,tail rotor drive shaft - failure,total (cause)
- Loss of control - in flight, hover
  - directional control - not possible, pilot in command
- In flight collision with terrain/water, descent - uncontrolled

## Analysis

THE HELICOPTER WAS BEING USED TO LIFT SEISMIC MATERIALS ON A 100 FT LONG LINE. AFTER LIFTING THE LOAD TO A HOVER AT ABOUT 10 TO 20 FT, THE PLT HEARD A LOUD 'BANG' WHICH WAS FOLLOWED BY A LOSS OF DIRECTIONAL CONTROL. THE HELICOPTER BEGAN UNCONTROLLED SPINNING & CRASHED MOMENTS LATER. WITNESSES REPORTED THAT THE TAIL ROTOR BLADES STOPPED ROTATING PRIOR TO THE HELICOPTER HITING THE GROUND. AN EXAM REVEALED  THAT THE AFT TAIL ROTOR DRIVESHAFT FLEXIBLE COUPLING, BENDIX PN; 369A5501, HAD FAILED. DUE TO DAMAGE OF THE FRACTURE SURFACE, THE MODE OF FAILURE COULD NOT BE DETERMINED.

## Aircraft

- Registration: [N8667F](https://openairdocs.org/deregistered/N8667F-1984-04-03), registration cancelled 1984-04-03, S/N 280272D (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: 280
- Airframe hours: 3551
- Engines: ALLISON 250-C20B 420 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Business, Part 133
- Operator: Rocky Mountain Helicopters
- Registered owner: Gatx Second Aircraft Corp.
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, August 24, 1983, 28 hours before
- Departed: WOODRUFF, UT
- Flight plan: Company VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 48; flight instructor, commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane, helicopter; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 6,800 total, 200 in this make and model, 180 in the last 90 days, 6 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 0° at 3 knots
- Visibility: 15 statute miles
- Lowest ceiling: none
- Temperature: 70 °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 19830912048629A](https://openairdocs.org/incident/19830912048629A), Sep 12, 1983: Hughes 369D, Woodruff, UT, Substantial damage. Lost tail rotor control during hover with a sling load. Impacted in a left spin. Tail rotor drive coupling failed.

## Other investigations on N8667F (1)

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 DEN79FTC19](https://openairdocs.org/ntsb/DEN79FTC19), Jul 1, 1979: Hughes 369D (N8667F), Labarge, WY, 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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