ANC03LA073 · Bell 206B
American Helicopters Bell 206B · Accident: total loss of engine power (mechanical failure) en route
From Red Devil Airport (RDV) to Aniak Airport (PANI)
Event
- NTSB case
- ANC03LA073
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Bell 206B
- Aircraft type
- Bell 206
- Category
- Helicopter
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N111MT
- Operator
- American Helicopters
- Onboard fatalities
- Unknown
- Route
- From Red Devil Airport (RDV), Red Devil, AKTo Aniak Airport (PANI), Aniak, AK
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- En route · cruise
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Total loss of engine power (mechanical failure)
- Also codedOther events the NTSB coded in the sequence, such as a wire strike after a loss of power. Flight Findings uses them for its kinds of event. Glossary
- Tree(s)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Fuel system, pc line › Loose
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The helicopter was operating as a Title 14, CFR Part 91, positioning flight in visual meteorological conditions when it had a total loss of engine power while in cruise flight. The pilot said the first indication of a problem was the illumination of the auto-relight indicator, followed by the engine fail light. He initiated an autorotation towards a clearing, but was unable to reach it. The helicopter impacted trees about 30 feet above the ground. During the inspection of the engine, the compressor discharge pressure line (Pc line) was removed at the compressor scroll, and compressed air was applied. Technicians reported air escaping at the Pc line's junction with the fuel control unit. The B-nut on the Pc line was loose at the fuel control unit. There was evidence of fretting on the B-nut fitting, and there were smears of orange torque seal material on the B-nut. No torque seal material was present on the B-nut fitting. The engine logbook indicated the fuel control unit was replaced by company mechanics 178 hours prior to the accident.
Probable cause
The compressor discharge pressure line (Pc line) B-nut coming loose at the fuel control unit, which resulted in a total loss of engine power, and subsequent in-flight collision with trees during an autorotation. A factor associated with the accident was the improper installation of the Pc line B-nut by company maintenance personnel.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ANC03LA073
- Event ID
- 20030716X01116
- Case number
- ANC03LA073
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: local date, investigation status, coordinates. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 2003-07-10.
- API snapshot SHA-256: 1befe6b9069878c7721e6d3c63b6d62144da5b5639fc488c855b08306f733855; retrieved 2026-09-21T19:25:31.103Z.