Eurocopter AS 350 B3 N341HP accident near Napa, California

Probable cause

The flight instructor’s improper use of the collective control during a practice hovering autorotation, which resulted in a hard landing.

NTSB analysis

The flight instructor reported that while hovering about 3 feet above the ground, he performed an autorotation demonstration for the second pilot. Although the flight instructor raised the collective to arrest the descent before landing, the helicopter made a firm landing, which resulted in substantial damage to the tailboom. The flight instructor reported no preimpact mechanical malfunction or failure that would have precluded normal operation.

The Federal Aviation Administration’s helicopter flying handbook identifies the proper techniques for practice autorotation maneuvers from altitude and indicates that one of the common errors that can occur during hovering autorotations is the pilot’s failure to apply up-collective pitch properly, which can result in a hard landing.

Text from the NTSB. Open the NTSB docket for WPR12TA120 for the full record.