Bell 206B N38EA accident near Franklin, California

Probable cause

The student pilot's failure to maintain rotor rpm during the practice autorotation.

NTSB analysis

The student pilot was practicing autorotations and hovering maneuvers, and reported no anomalies with the helicopter during that period. He continued to practice 180-degree autorotations to the right in a nearby open field, and he successfully completed the first autorotation. During the second autorotation, he confirmed that all flight instruments were indicating normal engine operation, but noted that his airspeed was too slow. He attempted to apply corrective control inputs as the descent rate increased. About 100 feet above ground level, he heard the low rotor warning horn and immediately countered by quickly rolling the throttle to full power while applying up-collective. The helicopter did not respond to his inputs in the manner he was expecting, and he performed a run-on landing rather than continue with the attempted recovery. The helicopter then impacted the ground hard, spreading the skids, and then rolled onto its side. The pilot reported that the engine was still operating as he exited. A post impact fire subsequently consumed the majority of the helicopter's components. Subsequent examination of the remnants did not reveal any anomalies with the airframe or engine that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for WPR11TA274 for the full record.