Final Report: Turbine blade failed
McDonnell Douglas MD 369D, Columbus, Mont., May 28, 2007–The Safety Board blamed this accident, which resulted in the death of a crewmember, on the fatigue failure of a turbine blade caused by a localized overtemperature of the turbine section due to nonuniform fuel distribution by the fuel nozzle. The helicopter was hovering at about 120 agl, inspecting a powerline structure, when it suddenly lost all power. The pilot attempted an autorotation, but the close proximity of the structure restricted maneuverability. The helicopter, which was operated by Haverfield, was destroyed in the crash and resulting fire.
Despite a revision of the Rolls-Royce operation and maintenance manual specifying that the fuel nozzle be removed, inspected and cleaned as part of each 100-hour inspection, investigators found that this procedure had been performed during only two of the last seven 100-hour inspections. At the time of the accident, the engine had logged about 236 hours since the last nozzle inspection and cleaning.