Incident Overview
A helicopter lost engine power while on final approach to an offshore oil platform. The pilot initiated an autorotation and subsequently landed hard on the rough, choppy ocean surface. Following the landing, the helicopter sank to the bottom of the sea.
Fuel Considerations
According to fuel consumption calculations provided by the operator, the helicopter could have been at or near fuel exhaustion at the time of the accident. However, because the aircraft sank, it was not possible to verify the remaining fuel or examine aircraft systems.
Investigation Outcome
Due to the inability to inspect the wreckage and fuel system, the reason for the loss of engine power could not be determined conclusively. The investigation did not identify a definitive cause.