# NTSB SEA92LA011: Hughes 369D, Hyder, AK, October 11, 1991

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: October 11, 1991, 14:00 local (21:00 UTC)
- Place: Hyder, AK
- Coordinates: 55.970283, -130.04071 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=55.9703&lon=-130.0407&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious
- Status: Completed, report May 5, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 41605
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA92LA011
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41605/pdf
- Page: https://openairdocs.org/ntsb/SEA92LA011

## Probable cause

THE FAILURE OF THE TAIL ROTOR HUB ASSEMBLY.  FACTORS INCLUDE UNSUITABLE TERRAIN, AND HIGH VEGETATION.

## Sequence of events

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

- Airframe/component/system failure/malfunction, cruise
  - rotor system,tail rotor hub - undetermined (cause)
- In flight collision with terrain/water, descent - uncontrolled
  - terrain condition - none suitable (contributing factor)
  - terrain condition - high vegetation (contributing factor)

## Analysis

THE HUGHES 369D WAS RETURNING TO A LOAD PICK UP POINT WHEN THE PILOT FELT AND HEARD A VIBRATION, WHICH SEEMED TO BE COMING FROM THE AREA OF THE TAIL ROTOR.  THE PILOT ROLLED BACK THE POWER, AND BEGAN AN AUTOROTATION.  AS HE INCREASED POWER AND COLLECTIVE, TO MANEUVER FOR THE FLARE, HE HEARD TWO LOUD BANGS COME FROM THE TAIL ROTOR AREA.  THIS WAS FOLLOWED IMMEDIATELY BY AN UNCONTROLLED ROTATION OF THE AIRFRAME.  HE ATTEMPTTED TO APPLY FULL UP COLLECTIVE JUST PRIOR TO IMPACT, BUT HIT THE TERRAIN WITH CONSIDERABLE FORCE.

## Aircraft

- Registration: CGKHR (not matched to a registry record)
- Reported make and model: HUGHES 369D
- Category: Helicopter
- Serial number: 690531D
- Airframe hours: 5145
- Engines: ALLISON 250-C20B 375 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Other work use, Part 133
- Operator: Vancouver Helicopters
- Registered owner: Vancouver Helicopters
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, September 18, 1991, 17 hours before

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 44; commercial; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 5,500 total, 4,000 in this make and model, 5,450 as pilot in command, 300 in the last 90 days, 50 in the last 30 days, 4 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 45° at 10 knots
- Visibility: 8 statute miles
- Lowest ceiling: 3,500 ft overcast
- Temperature: 39 °F

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.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.