ANC83FA122 · Aerospatiale AS-350D
Aerospatiale AS-350D · Accident: total loss of engine power (mechanical failure) en route
From an unrecorded airport to Tom Madsen (Dutch Harbor) Airport (DUT)
Event
- NTSB case
- ANC83FA122
- 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
- 0
- 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
- Charter & commuter
- 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
Aerospatiale AS-350D
- Aircraft type
- Aerospatiale AS-350
- 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
- N141EH
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From not recordedTo Tom Madsen (Dutch Harbor) Airport (DUT), Dutch Harbor, 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 135: Air Taxi & Commuter
- 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)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Destroyed
Cause areas
- Company maintenance personnel › Maintenance, improper
- Engine assembly, bearing › Failure, total
- Fluid, oil › Starvation
- Lubricating system › Blocked(partial)
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
APRX 2 MIN AFTER TAKEOFF, THE PLT & PASSENGERS HEARD A LOUD MUFFLED BOOM FROM BEHIND THE FIREWALL, THEN THE ROTOR RPM BEGAN TO DECAY. THE PLT ENTERED AN AUTOROTATION & SELECTED A LANDING AREA. HE NOTED THAT THE ENG WAS NOT DRIVING THE ROTOR SYS, SO HE SHUT IT DOWN TO REDUCE THE POSSIBILITY OF FIRE WHILE LANDING. DURING AN EMERGENCY LANDING ON SLOPING, MOUNTAINOUS TERRAIN, THE HELICOPTER ROLLED OVER, AND SUBSEQUENTLY, IT CAME TO REST IN A RAVINE AT THE BOTTOM OF THE SLOPE. A TEARDOWN OF THE ENG REVEALED THAT THE #3 BEARING, PN 4-301-051-02, HAD FAILED & THAT THE OIL JET FOR THE BEARING WAS CLOGGED. REPORTEDLY, MAINTENANCE PERSONNEL WERE AWARE THAT A DIFFERENTIAL PRESSURE CHECK, TO DETECT CLOGGING TO THE #2 & #3 PACKAGED OIL JETS, WAS 7 TO 8 PSI. THIS WAS 2 TO 3 PSI TOO HIGH & INDICATED CLOGGING OF THE OIL JETS. (THIS PROCEDURE WAS OUTLINED IN LYCOMING SVC BULLETIN LTS101A-17-0014). HOWEVER, THE DISCREPANCY WAS NOT ENTERED IN THE ENG MAINTENANCE LOGS.
Verbatim NTSB analysis from the NTSB dataset
Sources
NTSB record ANC83FA122
- Event ID
- 20001214X43555
- Case number
- ANC83FA122
- 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. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 1983-07-12.
- API snapshot SHA-256: 82d640b3eedb1ec2a65fed8adeeee4be2174cb5ad0ff8504a86780317d8aad17; retrieved 2026-09-18T20:56:47.050Z.