# NTSB SEA88LA143: Bell UH-1E, N151LC, North Bend, OR, August 4, 1988

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: August 4, 1988, 09:30 local (16:30 UTC)
- Place: North Bend, OR
- Coordinates: 43.406236, -124.22311 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=43.4062&lon=-124.2231&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 1 minor
- Status: Completed, report September 19, 1989
- Report: Approved by Office Director
- NTSB case key (mKey): 40857
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA88LA143
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/40857/pdf
- Page: https://openairdocs.org/ntsb/SEA88LA143

## 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,intermediate gearbox(42 deg) - fatigue (cause)
- Forced landing, landing
  - autorotation
- In flight collision with terrain/water, landing - flare/touchdown
  - terrain condition - none suitable (contributing factor)

## Analysis

DRG A LOGGING OPN, THE PLT NOTED AN APPARENT TRANSMISSION MALFUNCTION. AN AUTOROTATIVE LANDING WAS MADE ON UNPREPARED TERRAIN & THE HELICOPTER WAS DAMAGED. AN INVESTIGATION REVEALED THE TAIL ROTOR DRIVE INPUT GEAR IN THE 42 DEG GEARBOX HAD FAILED FROM FATIGUE. N151LC WAS A MILITARY SURPLUS HELICOPTER. THE GEARBOX HAD BEEN OVERHAULED ON 6/15/87. THE OPERATOR'S RECORDS SHOWED IT HAD BEEN IN SERVICE FOR 373 HRS SINCE OVERHAUL.

## Aircraft

- Registration: [N151LC](https://openairdocs.org/deregistered/N151LC-1989-10-24), registration cancelled 1989-10-24, S/N 151875 (OpenAirDocs)
- Reported make and model: BELL UH-1E
- Registry model: [Bell UH-1L](https://openairdocs.org/model/bell-uh-1l) (registry code 1181401) (OpenAirDocs)
- Category: Helicopter
- Serial number: 151875
- Airframe hours: 8288
- Engines: LYCOMING T53-L-13B 1400 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Other work use, Part 133
- Registered owner: Green Mountain Helicopters
- Airworthiness certificate: Special, Restricted (Special)
- Last inspection: AAIP, August 2, 1988, 1 hours before

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 38; airline transport; instrument ratings: helicopter; medical: class 2, valid medical--no waivers/lim.; seat: left; flight hours: 7,805 total, 1,220 in this make and model, 7,612 as pilot in command, 86 in the last 90 days, 68 in the last 30 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 340° at 5 knots
- Visibility: 20 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 19880804039629A](https://openairdocs.org/incident/19880804039629A), Aug 4, 1988: Bell UH1E, North Bend, OR, Substantial damage. Autorotated into rough terrain after apparent power malfunction. Tail rotor gearbox case ruptured due fatigue.

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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