WPR14GA176 · Hughes OH 6 A
Hughes OH 6 A · Accident: loss of engine power (total) while maneuvering
From Hanksville Airport (KHVE) to Sandy Ranch, UT
Event
- NTSB case
- WPR14GA176
- 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
- Government
- 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 OH 6 A
- Aircraft type
- Hughes OH-6
- 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
- N37929
- Operator
- Usda Aphis WS Atoc
- Onboard fatalities
- Unknown
- Route
- From Hanksville Airport (KHVE), Hanksville, UTTo Sandy Ranch, UT
- Aircraft age
- About 47 years (built 1967)
- 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
- Public Aircraft
- 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
- Maneuvering · hover
- 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 engine power (total)
- 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
- Not determined › Not determined
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
During a hover about 50 ft above ground level over steeply sloped terrain, the helicopter suddenly made an uncommanded left yaw, and the rotor rpm started to drop. The pilot lowered the collective and performed an autorotation to a rock ledge. After touching down on the ledge, the helicopter tipped over and tumbled downslope about 60 ft, and the tailboom was severed from the helicopter.
The rotor blade damage observed during the postaccident wreckage examination was consistent with low-rotor energy at the time of ground impact. Postaccident examination of the engine, rotor drive system, and fuel control unit revealed no anomalies that would have precluded normal operation. The engine's damaged external components were replaced, and a test run was conducted. The engine started and produced full power. The helicopter's operating manual stated that an uncommanded left yaw and a drop in rotor rpm could be indications of a loss of engine power. Given the uncommanded left yaw and drop in rotor rpm during the flight, it is likely that the engine lost power; however, the reason for the loss of engine power could not be determined.
Probable cause
A loss of engine power while the helicopter was hovering for reasons that could not be determined because postaccident examination of the engine and rotor drive system revealed no evidence of a mechanical malfunction or failure that would have precluded normal operation.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR14GA176
- Event ID
- 20140429X35951
- Case number
- WPR14GA176
- 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: 90cd8ebfbbe801e6f9c1eb880c7de5bd81b0aebf09e093de3d0d0e6c57d5f309; retrieved 2026-09-15T23:33:43.649Z.