CEN20LA282

A partial loss of engine power for reasons that could not be determined based on available evidence.

The pilot of the helicopter was conducting an aerial survey about 30 ft above the ground when the engine lost partial power. The pilot performed an autorotation to swampy terrain, and upon landing, the helicopter settled to the left and the main rotor blades impacted the ground. One main rotor blade and the main rotor pitch links sustained substantial damaged. An engine run was conducted after the wreckage was recovered. The engine started and was run at partial power while still installed in the accident helicopter using fuel that remained in the fuel tanks. Both magnetos were checked and operated normally during the engine run. No anomalies were noted with the engine. Weather conditions at the nearest weather reporting station about the time of the accident were not conducive to the development of carburetor icing. The reason for the partial loss of engine power could not be determined based on the available information.

On July 8, 2020, about 0945 central daylight time, a Robinson R-22 helicopter, N7186K, was substantially damaged when it was involved in an accident near Venice, Louisiana. The pilot was not injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 aerial observation flight. The pilot was conducting an aerial survey about 30 ft above ground level (agl) when the engine lost partial power. He successfully autorotated to swampy terrain, where the left skid sunk into the ground, the helicopter settled to the left, and the main rotor blades impacted the ground. One main rotor blade was bent and the main rotor pitch links were damaged. The helicopter was recovered and an engine run was conducted by a mechanic. The engine remained installed in the helicopter and the engine run was attempted using the battery and fuel that remained in the helicopter after the accident. The battery power was insufficient to start the engine, so the battery was replaced. The engine subsequently started and ran at idle power for several minutes before the mechanic advanced the throttle partially. He was unable to apply full throttle due to the condition of the wreckage. Once the engine power stabilized at the advanced power setting, he cycled the magneto switch from the “Both” position to the “Left” and “Right” positions. He reported the rpm decreased and stabilized each time the magneto switch was cycled to each position. The mechanic reported no anomalies during the engine run. Weather conditions, as reported at the nearest reporting facility, were not conducive to the development of carburetor icing.