Hughes 369 Safety Record

Fatigue failure of the overrunning clutch outer race and a subsequent inflight loss of power due to abnormal bending loads as a result of improper reassembly of the clutch subassembly following maintenance and the presence of microcracks on the clutch’s outer race.

An in-flight mechanical malfunction with the helicopter, which necessitated a ditching in the ocean. The reason for the malfunction could be determined because the helicopter sank and was not recovered.

A total loss of engine power for reasons that could not be determined because postaccident examination of the airframe and engine did not reveal any anomalies that would have precluded normal operation.

The pilot’s failure to prevent the helicopter from entering a vortex ring state (settling with power) condition during an external load operation, which resulted in the helicopter’s main rotor blades impacting the truck.

A partial loss of engine power due to fatigue fracture of the power turbine governor spring, causing a false pneumatic signal to the fuel control and a corresponding reduction in fuel flow.

Fatigue cracking of the oil line from the engine gearbox to the oil pressure gauge, which resulted in loss of engine lubricating oil, leading to seizure of the power turbine.

The pilot's failure to maintain aircraft control due to delayed remedial action during the encounter with the loss of tail rotor effectiveness. Contributing factors were the pilot's inadequate preflight performance planning, and the inadequate supervision by the US Forest Service personnel.

The flight crew's failure to maintain adequate altitude/clearance from a building, which resulted in contact with the building, dynamic rollover, and collision with terrain.

The pilot's misjudgment of clearance from the surface of the lake during the aerial application pass. The low altitude operation, glassy water, and his visual perception were contributing factors.

The improper installation of a bolt in the gas generator governor linkage by company maintenance personnel, which resulted in a loss of the bolt, a loss of engine power while maneuvering, and subsequent forced landing and collision with trees. Factors contributing to the accident were an inadequate preflight inspection by the pilot, and an uncommanded surge in engine power.

The entanglement of the fuel quantity sender float in the start pump wiring within the fuel tank as a result of the wiring not being properly secured. This rendered the fuel gauge inaccurate and the low fuel warning light inoperative which led to fuel exhaustion. The improper securing of the wiring was a result of unspecified maintenance personnel not identifying the unsecured condition. Contributing factors were the lack of adequate guidance in the maintenance manuals on inspection of the wiring and the low rotor RPM during the autorotation resulting in a hard landing.

A loss of engine power due to turbine blade separation as a result of hot corrosion damage to the turbine blades. Contributing to the accident was the pilot misjudging the flare at the completion of the autorotation resulting in a hard landing. The dark night was a factor.