# NTSB SEA90LA025: Hiller UH-12E, N9762C, Raymond, WA, November 29, 1989

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: November 29, 1989, 15:30 local (23:30 UTC)
- Place: Raymond, WA
- Coordinates: 46.640922, -123.629486 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=46.6409&lon=-123.6295&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report June 26, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 41155
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA90LA025
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/41155/pdf
- Page: https://openairdocs.org/ntsb/SEA90LA025

## Probable cause

LOSS OF ENGINE POWER DUE TO FATIGUE FAILURE OF THE IMPELLER. THE HELICOPTER WAS SUBSTANTIALLY DAMAGED AS A RESULT OF A ROLL-OVER ON UNEVEN TERRAIN.

## Sequence of events

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

- Loss of engine power(total) - mech failure/malf, maneuvering
  - compressor assembly,impeller - fatigue (cause)
- Forced landing, descent - emergency
- Roll over, landing - flare/touchdown
  - terrain condition - rough/uneven (contributing factor)

## Analysis

DURING AN EXTERNAL LOAD OPERATION, WHILE HAULING A LOAD UPHILL TO THE LANDING ZONE, THE PILOT HEARD A LOUD NOISE AND THE ENGINE BEGAN TO LOSE POWER. THE PILOT RELEASED THE LOAD AND AUTOROTATED TO A LANDING ON INCLINED TERRAIN. WHILE LANDING, THE HELICOPTER ROLLED OVER. DURING AN ENGINE TEARDOWN, A SECTION OF THE IMPELLER WAS FOUND TO HAVE FAILED FROM FATIGUE, WHICH RESULTED IN ADDITIONAL DAMAGE TO THE ENGINE AND A LOSS OF POWER.

## Aircraft

- Registration: [N9762C](https://openairdocs.org/aircraft/N9762C), registered now, S/N 2159, built 1962 (OpenAirDocs)
- Reported make and model: HILLER UH-12E
- Registry model: [Hiller UH-12E](https://openairdocs.org/model/hiller-uh-12e) (registry code 4360122) (OpenAirDocs)
- Registry engine: [Allison 250 series](https://openairdocs.org/engine/allison-250-series) (registry code 03014, turbo-prop) (OpenAirDocs)
- Category: Helicopter
- Serial number: 2159
- Airframe hours: 8066
- Engines: ALLISON 250-C20B 420 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Other work use, Part 133
- Operator: Glacier Helicopters
- Registered owner: Evergreen International
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, November 18, 1989, 42 hours before
- Departed: RAYMOND, WA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 38; commercial; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 3,293 total, 68 in this make and model, 2,475 as pilot in command, 68 in the last 90 days, 28 in the last 30 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 270° at 5 knots
- Visibility: 15 statute miles
- Temperature: 50 °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 19891129047839A](https://openairdocs.org/incident/19891129047839A), Nov 29, 1989: Hiller UH12E, Raymond, WA, Substantial damage. Engine failed during sling load. Jettisoned load. Autorotated. Rolled over. Impeller blades separated from fatigue.

## Other investigations on N9762C (3)

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 ATL00LA043](https://openairdocs.org/ntsb/ATL00LA043), Apr 20, 2000: Hiller UH-12ET (N9762C), Stonesboro, SC, substantial damage. Probable cause: The pilot's improper inflight decision not to refuel which resulted in fuel exhaustion and a total loss of engine power.
- [NTSB ANC78FA057](https://openairdocs.org/ntsb/ANC78FA057), Jul 23, 1978: Hiller UH12E3 (N9762C), Livengood, AK, substantial damage
- [NTSB ANC67A0006](https://openairdocs.org/ntsb/ANC67A0006), Jul 15, 1966: Hiller UH12E4 (N9762C), Fairbanks, AK, 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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