NTSB Identification: SEA07LA135.
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Accident occurred Monday, May 28, 2007 in Columbus, MT
Probable Cause Approval Date: 05/28/2008
Aircraft: Hughes 369D, registration: N765HV
Injuries: 1 Fatal,2 Serious.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
During a stable hover about 120 feet above ground level for the purpose of visually inspecting a power line support structure, the helicopter had a complete loss of engine power. The pilot's maneuvering options were limited by the support structure, and he attempted an autorotation to a forced landing. During that sequence of events the helicopter collided with terrain. The investigation determined that the engine's fuel nozzle was supplying a nonuniform fuel spray, leading to a localized over-temperature in the turbine section, which lead to turbine blade rub, the eventual fatigue separation of a second stage turbine blade, and the loss of engine power.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The fatigue failure of a turbine blade due to a localized over-temperature of the turbine section as result of a non-uniform fuel distribution by the fuel nozzle. Contributing to the accident was the close proximity of a power line support structure which restricted maneuverability for a successful autorotation. Full narrative available
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