History of Flight
On July 29, 2020, about 1000 Pacific daylight time, an American Eurocopter Corp. AS350B3 helicopter, registration N755AE, was destroyed when it impacted terrain near Pioche, Nevada. The pilot and passenger were fatally injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 positioning flight.
The pilot landed in mountainous terrain to survey a job site. The purpose of the flight was to reposition to a nearby fuel truck for refueling before external load operations. A witness reported dropping the pilot and passenger at the helicopter and seeing a cable laid out on the ground in front of it. The pilot indicated the cable was 70 feet long. The witness departed and shortly after received a call about smoke in the area, learning that the helicopter had crashed.
Damage Description
The helicopter came to rest in heavily treed terrain on its right side. There was no evidence of a postimpact fire. The helicopter was equipped with a long line cargo hook system. About 21 feet of steel long line cable impacted the main rotor blades and was found entangled in the separated tail rotor. The separated cable end exhibited a broomstrawed appearance and evidence of red paint transfer.
One tail rotor blade remained attached; the other was not located. The tail boom was broken off and partially attached by control cables. The tail rotor drive shaft separated and was found near the main wreckage. Both horizontal stabilizers remained attached to the tail boom. The main rotor blades remained attached to the rotor head but were broken midspan with multiple impact signatures. Skin material was found nearby. Flight control continuity was established from the cockpit to the main rotor head and tail rotor through separations consistent with impact damage.
The aft tail cone separated just forward of the vertical fin, which remained attached. The assembly was located about 365 feet from the main wreckage. The tail cone and vertical fin trailing edge exhibited abrasions consistent with cable contact.
Engine and Data Analysis
The engine remained attached with little impact damage. All fuel, oil, air, and electrical connections were intact. The gas generator and free turbine turned freely when rotated by hand. The axial compressor showed minor foreign object debris damage. Oil was present inside the exhaust pipe. Proper freewheel operation was confirmed. The rear tail rotor drive short shaft separated from the drive flange on the freewheel shaft; the flector group was torsionally splayed. The Module 5 reduction gearbox displayed signatures consistent with engine operation at the time of main rotor impact. Gearbox and accessory gearbox chip detectors were clean.
The engine data recorder was downloaded. Data from the accident flight indicated the engine was placed in flight, then reduced to idle near the end of the recording. During this sequence, main rotor speed decayed below that necessary to maintain lift. The data showed no anomalies that would have precluded normal flight.