American Eurocopter Corp AS350B3 N3951A accident near San Luis, Arizona

Probable cause

The pilot receiving instruction’s failure to properly recover the helicopter during an autorotative landing and the instructor pilot’s failure to intervene, which resulted in a hard landing.

NTSB analysis

According to the operator, the instructor and pilot receiving instruction were conducting hover autorotation training over cement that was visually obstructed by a hard packed dirt surface. On the third autorotation, the pilot under instruction established a hover at a slightly higher altitude than the previous two practice iterations. During recovery, the pilot receiving instruction executed the appropriate procedures, but the helicopter began to settle faster than expected and he was unable to sufficiently reduce the rate of descent. Subsequently, the helicopter landed hard and resulted in substantial damage to the tail boom.

The operator reported no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for WPR25LA189 for the full record.