ANC12CA032 · Robinson Helicopter R22 ALPHA
Pollux Aviation Robinson Helicopter R22 ALPHA · Accident: loss of control on ground while standing
From Wolf Lake Airport (4AK6) to Wolf Lake Airport (4AK6)
Event
- NTSB case
- ANC12CA032
- 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
Robinson Helicopter R22 ALPHA
- Aircraft type
- Robinson R22
- 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
- N121MR
- Operator
- Pollux Aviation
- Onboard fatalities
- Unknown
- Route
- From Wolf Lake Airport (4AK6), Palmer, AKTo Wolf Lake Airport (4AK6), Palmer, 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
- Standing · engine(s) operating
- 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
- Loss of control on ground
- 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
- Personnel issues › Action/decision
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The pilot flew to a practice area and landed the helicopter on what the pilot thought was firm snow. As he landed, the helicopter suddenly broke through the surface and its tailrotor struck the snow. The pilot repositioned the helicopter and the tailrotor gearbox chip detector light illuminated. An examination showed that the tailrotor driveshaft had sheared.
Probable cause
The pilot's selection of unsuitable terrain for landing, which resulted in a tailrotor strike.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ANC12CA032
- Event ID
- 20120422X33539
- Case number
- ANC12CA032
- 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, coordinates. 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: a0e68bc2697e3a1740cb1bf2b2753fe9def3c1db2b50e9f989a5bab854624b34; retrieved 2026-09-15T17:51:38.850Z.