Hughes OH 6 accident near Bullfrog, Utah, April 29, 2014
On April 29, 2014 at about 4:28 pm local time, a 1967 Hughes OH 6 (helicopter), registered N37929, was substantially damaged in an accident during maneuvering (hover) near Bullfrog, Utah (Bullfrog Basin Airport). It was a public-use flight (federal) under public-use (government) rules. 2 people were seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
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.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 29, 2014 · about 4:28 pm local time
- Place
- Bullfrog, Utah · Bullfrog Basin Airport · map
- Type
- Accident
- Injuries
- 2 people were seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Hughes OH 6 A, built 1967 · all OH 6s on the register
- Registration
- N37929 · no longer on the register · serial 67-16133
- Damage
- Substantial damage
- Flight
- Public-use flight (federal) · public-use (government) rules
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Loss of engine power (total) during maneuvering (hover) defining event
The NTSB's findings
- cause Not determined › Not determined › (general) › (general) › Unknown/Not determined
- Environmental issues › Physical environment › Terrain › Sloped/uneven › Contributed to outcome
Pilot
- Certificate: commercial pilot
- Ratings: rotorcraft: helicopter
- Flight time: 3,263 hours in all; 1,000.5 in this make and model; 189.1 in the last 90 days; 60.7 in the last 30 days; 3,202 as pilot in command
- Last flight review: May 17, 2012
- Medical certificate: Class 2 (without waivers/limitations)
- Seat: rgt
- Injury: serious injuries
The aircraft
- Airframe total time: 19,761.1 hours
- Last inspection: approved inspection programme, March 21, 2014
- Maximum gross weight: 2,550 lb
- Seats: 2
- Landing gear: fixed
- Engine: Rolls Royce 250-C20B (turboshaft); 4,172 hours total
The flight
- Departed from: KHVE Hanksville UT at 3:30 pm
- Destination: Sandy Ranch UT
Weather at the time
- Light: daylight
- Wind: from 060° at 14 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 55°F (13°C), dew point 7°F (-14°C)
- Altimeter: 30.32 inHg
- Observation at 4:53 pm from KPGA, 67 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.