Prism Helicopters Hughes 500D accident
Hughes 500D · Accident: loss of control on ground while standing
From Ambler, AK to Ambler, AK
Event
- NTSB case
- ANC11CA056
- 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
- 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
Hughes 500D
- Aircraft type
- Hughes 500
- 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
- C-GLHQ
- Operator
- Prism Helicopters
- Onboard fatalities
- Unknown
- Route
- From Ambler, AKTo Ambler, 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
- 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 › Task performance
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The helicopter pilot landed a high skid, turbine-powered helicopter at a remote drilling site, and the three passengers disembarked. The remote landing site was constructed of 6-inch by 6-inch wooden beams, which required that the pilot land perpendicular to and on the beams with the helicopter's skids. The pilot reported that after landing he retarded the engine throttle to flight idle to begin the mandatory 2 minute engine cool down procedure. He then got out of the helicopter to check the placement of the helicopter's skids on the beams, and it subsequently tipped backwards, with the tail rotor striking terrain. A postaccident inspection revealed that while landing, the pilot inadvertently placed the helicopter's skids behind the aft wooden beam, and the helicopter tipped backwards once the pilot exited the helicopter. The pilot said there were no preimpact mechanical problems with the helicopter. The helicopter sustained substantial damage to the tail boom, tail rotor drive system, and tail rotor gearbox.
Probable cause
The pilot's misalignment of the helicopter on the landing structure.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ANC11CA056
- Event ID
- 20110630X35227
- Case number
- ANC11CA056
- 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. 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: c9dc4540a77ca9a388eae398afddffc85684ee4af662c4317ffe96514e553d47; retrieved 2026-09-15T16:22:43.966Z.