# NTSB ANC92FA044: Bell 214B-1, N314RM, Hobart Bay, AK, March 6, 1992

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Field investigation · Final report
- Date: March 6, 1992, 11:30 local (15:30 UTC)
- Place: Hobart Bay, AK
- Location: 57.4052° N, 133.4132° W: Placed by OpenAirDocs: center of Hobart Bay, AK, within about 6 miles (OpenAirDocs)
- Nearby events: https://openairdocs.org/map.md?lat=57.4052&lon=-133.4132&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 2 serious
- Status: Completed, report December 9, 1993
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 5641
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC92FA044
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/5641/pdf
- Page: https://openairdocs.org/ntsb/ANC92FA044

## Probable cause

FATIGUE FAILURE OF THE COMPRESSOR ASSEMBLY IMPELLER, AND INADEQUATE QUALITY CONTROL BY THE MANUFACTURER. A FACTOR WHICH CONTRIBUTED TO THE ACCIDENT WAS THE MOUNTAINOUS/HILLY TERRAIN.

## Analysis

THE HELICOPTER WAS HOVERING APPROX 200 FT ABOVE THE LOG WHICH WAS BEING ATTACHED TO THE CARGO HOOK. THE PILOTS HEARD A LOUD BANG FOLLOWED BY A LOSS OF ENGINE POWER. THE HELICOPTER AUTOROTATED INTO STEEP UNEVEN TERRAIN, THE ONLY AREA AVAILABLE. EXAMINATION OF THE ENGINE REVEALED FATIGUE FAILURE OF THE CENTRIFUGAL IMPELLER ENCOMPASSING A 60 DEG ARC. THIS SECTION SEPARATED FROM THE ENGINE AND HELICOPTER. ANALYSIS OF THE IMPELLER SHOWED THAT THE COOLING HOLES, ASSOCIATED ONLY WITH THE T5508D ENGINE, DID NOT HAVE THE PRESCRIBED RADIUS, AND CRACKS WERE FOUND EMANATING FROM THE OTHER COOLING HOLES. THE ENGINE RECORDS SHOW THAT THE IMPELLER HAD 5592.0 CYCLES WHEN INSTALLED IN THIS ENGINE IN APRIL 1991. THE COMPONENT SERVICE LIFE LIMIT OF THE IMPELLER IS 16,600 CYCLES.

## 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, hover
  - compressor assembly,impeller - fatigue (cause)
  - inadequate quality control, manufacturer (cause)
- Forced landing, landing - flare/touchdown
  - autorotation - performed, pilot in command
- In flight collision with terrain/water, landing - flare/touchdown
  - terrain condition - none suitable (contributing factor)
  - terrain condition - mountainous/hilly (contributing factor)

## Aircraft

- Registration: [N314RM](https://openairdocs.org/deregistered/N314RM-1992-06-19), registration cancelled 1992-06-19, S/N 28041 (OpenAirDocs)
- Reported make and model: Bell 214B-1
- Registry model: [Bell 214B-1](https://openairdocs.org/model/bell-214b-1) (registry code 1182105) (OpenAirDocs)
- Category: Helicopter
- Serial number: 28041
- Airframe hours: 8116
- Engines: LYCOMING T5508D 2950 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Part 133
- Operator: Rocky Mountain Aerologging Inc
- Registered owner: Rocky Mountain Helicopters Inc
- Airworthiness certificate: Standard, Normal
- Last inspection: AAIP, March 4, 1992, 17 hours before
- Flight plan: Company VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 46; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: helicopter, airplane; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 13,000 total, 3,500 in this make and model, 12,000 as pilot in command, 208 in the last 90 days, 56 in the last 30 days, 8 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 99 statute miles
- Lowest ceiling: none
- Temperature: 45 °F
- Altimeter: 29.00 inHg

## 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 19920306005209A](https://openairdocs.org/incident/19920306005209A), Mar 6, 1992: Bell 214B, Hobart Bay, AK, Substantial damage. Engine lost power during sling load hover. Autorotated in slash and stumps. Centrifugal compressor fractures.

## Other investigations on N314RM (2)

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 SEA90LA148](https://openairdocs.org/ntsb/SEA90LA148), Jul 28, 1990: Bell BH-214 (N314RM), Thompson Falls, MT, substantial damage. Probable cause: CREW'S ENCOUNTER WITH SOFT TERRAIN WHILE ATTEMPTING AN AUTOROTATION LANDING AFTER THE FAILURE OF THE MAIN ROTOR DRIVE SYSTEM.
- [NTSB SEA85LA060](https://openairdocs.org/ntsb/SEA85LA060), Feb 19, 1985: Bell 214B1 (N314RM), Lowell, OR, 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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