ANC20LA089 · Eurocopter AS 350 B3
Pathfinder Aviation Eurocopter AS 350 B3 · Accident: part(s) separation from aircraft en route
From Trophy Lodge Heliport (72AK) to Merrill Field (MRI)
Event
- NTSB case
- ANC20LA089
- 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
Eurocopter AS 350 B3
- Aircraft type
- Eurocopter 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
- N354PA
- Operator
- Pathfinder Aviation
- Onboard fatalities
- Unknown
- Route
- From Trophy Lodge Heliport (72AK), Delta Junction, AKTo Merrill Field (MRI), Anchorage, AK
- Aircraft age
- About 20 years (built 2000)
- 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
- Defining eventThe 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
- Part(s) separation from aircraft
- 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
- Aircraft › Aircraft structures
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
While in cruise flight, at about 700 ft above ground level and 110 kts, a “sudden loud bang” and associated left yaw was experienced as the sliding left side cabin door vacated the helicopter from the closed position. The door impacted a main rotor blade during the separation sequence, which resulted in substantial damage. Subsequently an emergency landing was made to a nearby grass area with no further incident.
Airbus Helicopters has two Alert Service Bulletins (ASB) out for the cabin doors on the AS350-B3. The operator reported that the ASBs from the helicopter manufacturer regarding the cabin doors had not been complied with prior to the accident.
During a post-accident examination, the FAA inspector reported that he was not able to find any definitive reason for the departure of the door. He added that the door rollers were displaced and were not recovered, and a partial slide piece on the lower rail was not recovered either. Since the door rollers were not recovered, they were not able to be examined, and therefor their condition and function could not be tested.
Airbus Helicopters has two Alert Service Bulletins (ASB) published in response to door seperations that occurred as a result of door roller failures on AS350-B3 helicopters. The operator reported that these ASBs had not been complied with prior to the accident. Because the affected components were not recovered, the investigation could not determine if compliance with these ASBs could have prevented the accident.
Airbus noted that the damage was consistent with the door lock not being effective due to the presence of a cargo box that was stored in the cabin that interfered with the door, which resulted in the door opening and separating in flight due to the interference load introduced by the cargo box in the cabin.
Although some affected components were not recovered and examined, the accident is consistent with the door lock failing inflight, likely due to interference between the door and the cargo box.
Probable cause
Failure of the door lock due to interference between the door and a cargo box.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ANC20LA089
- Event ID
- 20200908X83855
- Case number
- ANC20LA089
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
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: investigation status, cause areas. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 3004a32e82e6d15b60d7107247b1dbf94492ff1222bda7f54e485864eb705861; retrieved 2026-09-16T13:00:48.769Z.