# NTSB ANC83FA144: Bell 206L-1, N1081K, Bettles, AK, August 13, 1983

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Field investigation · Final report
- Date: August 13, 1983, 10:35 local (18:35 UTC)
- Place: Bettles, AK
- Coordinates: 67.239852, -152.270507 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=67.2399&lon=-152.2705&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 6 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB office: Alaska Regional Office
- NTSB case key (mKey): 4050
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC83FA144
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/4050/pdf
- Page: https://openairdocs.org/ntsb/ANC83FA144

## 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
  - fluid,fuel - contamination (contributing factor)
  - fuel system,screen - inadequate (cause)
  - acft/equip,inadequate design, manufacturer (cause)
  - electrical system,electric switch - inoperative
  - fuel system - failure,partial
  - fluid,fuel - low level (contributing factor)
  - precautionary landing - not performed, pilot in command
  - fluid,fuel - starvation (cause)
- Forced landing, landing - flare/touchdown
  - autorotation - not identified, pilot in command
- Hard landing, landing - flare/touchdown

## Analysis

ACCORDING TO THE PLT, THE LOW FUEL WARNING LIGHT ILLUMINATED WHEN THE FUEL GAGE WAS INDICATING 200 LBS. HE REPORTED HE COULD SEE THE ARPT LIGHTS & ELECTED TO CONTINUE THE FLT. AFTER ARRIVING, HE TERMINATED HIS APCH TO A 30 TO 50 FT HOVER WITH NO FORWARD SPEED. AS HE APPLIED FORWARD CYCLIC TO HOVER TO THE REFUELING AREA, THE ENG FLAMED OUT. SUBSEQUENTLY, THE HELICOPTER LANDED HARD & THE MAIN ROTOR BLADES STRUCK THE TAIL BOOM. AN EXAM REVEAL THERE WAS ENOUGH FUEL REMAINING IN THE MAIN CELL FOR APRX 20 MIN OF FLT. DISASSEMBLY OF THE SYS REVEALED THAT DEBRIS (DIRT & ZINC CHROMATE PAINT CHIPS) WAS IN THE FILTERS. THE FILTER SCREEN HAD OPENINGS OF .020 INCH. PARTICLES WERE FOUND IN THE FLOW SWITCHES. HOWEVER, THE CLEARANCE BETWEEN THE FLOW SWITCH PLUNGER & THE WALL OF THE CASING WAS ONLY .012 INCH. EVIDENCE WAS FOUND TO INDICATE THIS RENDERED A FLOW SWICH INOPERATIVE SO THAT FUEL WOULD NOT TRANSFER FROM THE MAIN CELL TO THE REAR CELL WHERE IT COULD BE USED BY THE ENG.

## Aircraft

- Registration: [N1081K](https://openairdocs.org/aircraft/N1081K), registered now, S/N 45407, 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-C20 series](https://openairdocs.org/engine/allison-250-c20-series) (registry code 03020, turbo-prop) (OpenAirDocs)
- Category: Helicopter
- Serial number: 45407
- Airframe hours: 2499
- Engines: ALLISON 250-C28B 435 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Part 135
- Registered owner: Offshore Logistic Inc.
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, August 13, 1983, 2 hours before
- Departed: MTF, FAIRBANKS, AK
- Destination: BTT, BETTLES, AK
- Flight plan: VFR
- Airport: BTT, Bettles, runway 1, 5,200 × 160 ft, gravel

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 43; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: helicopter; medical: class 1, valid medical--no waivers/lim.; seat: right; flight hours: 5,789 total, 40 in this make and model, 4,827 as pilot in command, 41 in the last 90 days, 2 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 20° at 7 knots
- Visibility: 15 statute miles
- Lowest ceiling: 5,000 ft broken
- Temperature: 45 °F, dew point 39 °F
- Altimeter: 29.00 inHg
- Observed at: BTT

## 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 19830813075829A](https://openairdocs.org/incident/19830813075829A), Aug 13, 1983: Bell 206L1, Bettles, AK, Substantial damage. Paint chips in fuel clogged flow limit switches and ejector pumps, preventing transfer and causing fuel starvation.

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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