# NTSB ANC84LA071: Bell 206L-1, N1078N, Mt Mckinley Vil, AK, May 16, 1984

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: May 16, 1984, 10:55 local (18:55 UTC)
- Place: Mt Mckinley Vil, AK
- Coordinates: 63.779495, -148.519805 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=63.7795&lon=-148.5198&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 3 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 4290
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC84LA071
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/4290/pdf
- Page: https://openairdocs.org/ntsb/ANC84LA071

## 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, cruise - normal
  - fuel system,line - blocked(partial) (cause)
- Forced landing, descent - emergency
- In flight collision with object, landing
  - object - tree(s)

## Analysis

THE HELICOPTER EXPERIENCED AN ENGINE FAILURE WHILE CRUISING AT ABOUT 600 FT AGL. THE PILOT MADE A FORCED LANDING DURING WHICH THE MAIN ROTOR BLADES COLLIDED WITH TREES. EXAMINATION OF THE AIRCRAFT FUEL SYSTEM REVEALED THAT THE CHECK VALVES LOCATED IN THE FUEL LINES WHICH TRANSFER FUEL FROM THE FORWARD FUEL CELL TO THE AFT FUEL CELL WERE WORN AND ONE OF THE CHECK VALVES WAS STUCK IN THE CLOSED POSITION. FURTHER EXAMINATION OF THE FUEL MANIFOLD, WHICH CONTAINS TWO MORE POPPET VALVES, REVEALED THAT ONE OF THE POPPET PARTICLES WAS FOUND IN ALL OF THESE CHECK VALVES. WITH BOTH POPPET VALVES CLOSED, THE FUEL BOOST PUMPS WILL NOT SUPPLY PRESSURE TO THE SINGLE FUEL LINE, TO THE FUEL PRESSURE TRANSDUCER OR TO THE ENGINE.

## Aircraft

- Registration: [N1078N](https://openairdocs.org/aircraft/N1078N), registered now, S/N 45389, built 1980 (OpenAirDocs)
- Reported make and model: BELL 206L-1
- Registry model: [Bell Helicopter Textron 206L-1](https://openairdocs.org/model/bell-helicopter-textron-206l-1) (registry code 1182107) (OpenAirDocs)
- Registry engine: [Allison 250 SER 317HP](https://openairdocs.org/engine/allison-250-ser-317hp) (registry code 03011, turbo-shaft) (OpenAirDocs)
- Category: Helicopter
- Serial number: 45389
- Airframe hours: 3209
- Engines: Detr. Diesel 250-C28B 435 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Part 135
- Operator: Air Logistics Of Ak  Inc.
- Registered owner: Security Pac. Equip. Leasing
- Airworthiness certificate: Standard, Normal
- Last inspection: Continuous airworthiness, May 12, 1984, 11 hours before
- Departed: DENALI AIRSTRIP, AK
- Flight plan: Company VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 41; flight instructor, commercial; airplane ratings: single-engine land; instrument ratings: helicopter; medical: class 2, valid medical--no waivers/lim.; seat: right; flight hours: 3,328 total, 37 in this make and model, 3,050 as pilot in command, 97 in the last 90 days, 5 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 0° at 10 knots, gusting 20
- Visibility: 100 statute miles
- Temperature: 48 °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 19840516024819A](https://openairdocs.org/incident/19840516024819A), May 16, 1984: Bell 206L1, Mt Mckinley Vil, AK, Substantial damage. Engine flamed out. Made a hard auto rotation landing to reach the strip. Both fuel line poppet valves jammed closed

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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