ERA23FA163 · Larry F Preiss AR-1

The pilot had recently resumed flying and was on a local flight in the experimental amateur-built gyroplane. After the pilot departed from his home airport, he flew for about 10 nautical miles and conducted several maneuvers. A review of video footage recovered from a camera onboard the gyroplane revealed that the engine could be heard surging before the engine noise stopped, consistent with a loss of engine power, and the gyrocopter began to descend. The pilot then appeared to conduct a forced landing attempt toward an open field. As the gyroplane neared the ground, it struck a power line that bordered the field, after which it rapidly pitched downward, and impacted the ground. A postaccident examination of the engine revealed no evidence of any preimpact mechanical anomalies that would have precluded normal operation. Fuel samples obtained from the gyroplane’s fuel tank contained a significant amount of water contamination. Engine test runs using the contaminated fuel demonstrated that the engine initially ran normally when the fuel/water mixture was agitated, but that the engine lost power and eventually stopped all together once the water and fuel settled and separated. When clean fuel was provided, the engine operated normally without any issues. The presence of water contamination in the fuel system likely resulted in the loss of engine power observed in the video recording. The pilot's subsequent forced landing approach was affected by the presence of the powerline along his flight path, which he likely did not see prior to impacting it.

Verbatim NTSB analysis and probable cause from the NTSB dataset