Hughes OH 6 N37929

Summary

On 29 April 2014 at about 16:28 local time, a Hughes OH 6 registered N37929, operated by Usda Aphis WS Atoc, was involved in an accident near Bullfrog, Utah, United States. 2 people were on board and 2 were seriously injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

29 April 2014 at 16:28

Classification

Accident

Location

Bullfrog, Utah, United States

Nearest airport

Bullfrog Basin Airport (KU07)

Coordinates

37.5661, -110.9500

Aircraft

Hughes OH 6

Registration

N37929

Category

Helicopter

Year built

1967

Engines

1

Operator

Usda Aphis WS Atoc

Operating rule

Public Use

Phase of flight

Not recorded

Route

Hanksville → Sandy Ranch

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

WPR14GA176

2 people were seriously injured.

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.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full 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.

Quoted verbatim from the NTSB record.