Accident Description
The helicopter was conducting a positioning flight under Title 14, CFR Part 91, and was operating in visual meteorological conditions. During cruise flight, the pilot reported the first indication of a problem was the illumination of the auto-relight indicator, followed by the engine fail light. The pilot initiated an autorotation toward a clearing but was unable to reach it. The helicopter subsequently impacted trees approximately 30 feet above the ground.
Engine Inspection
During the post-accident inspection of the engine, the compressor discharge pressure (Pc) line was removed at the compressor scroll, and compressed air was applied. Technicians observed air escaping at the junction of the Pc line with the fuel control unit. The B-nut securing the Pc line at the fuel control unit was found loose. Examination revealed evidence of fretting on the B-nut fitting, along with smears of orange torque seal material on the B-nut. No torque seal material was present on the B-nut fitting itself.
Maintenance History
The engine logbook indicated that the fuel control unit had been replaced by company mechanics approximately 178 flight hours prior to the accident.