Helicopter Sinks in Reservoir After Engine Failure (N99TV)

Accident Details

A helicopter was being flown to a maintenance facility to address a 'rotor vibration' detected by the pilot. During cruise flight over a reservoir, a loss of engine power occurred. The power loss was attributed to the failure of the #2-1/2 bearing due to oil starvation. Investigation revealed that the oil starvation resulted from an obstruction in the bearing oil feed tube caused by a particle of foreign material. Evidence indicated that the foreign material was introduced into the system during an overhaul approximately 9 flight hours before the accident.

Emergency Response

The pilot executed an autorotation through dense fog to the surface of the reservoir. The reservoir contained patches of ice. After landing, the helicopter sank in 190 feet of water. At the time, the water temperature was 30 °F, the air temperature was 34 °F, and the wind was from 170° at 8 knots. According to available information, useful conscious time under these conditions would have been about 15 minutes. The first rescue personnel reached the pilot approximately 45 minutes after the accident. The pilot was the only person on the surface at that time.