Mcdonnell Douglas Heli Co 369FF N911BL accident near Las Vegas, Nevada

Probable cause

The pilot’s failure to maintain sufficient airspeed while performing a 270-degree practice autorotation with a gusting tailwind at a high-density altitude.

NTSB analysis

The pilot-in-command (PIC), who was giving instruction, was demonstrating a 270-degree autorotation in a gusting west wind at a density altitude of about 5,100 feet. The PIC began the autorotation heading south and turned left; the helicopter experienced a tailwind during the turn. The PIC reported that, because of the tailwind, soon after commencing the autorotation, he increased his bank angle to maintain his ground reference to the intended touchdown point. The pilot receiving instruction stated that, moments later, the helicopter was in a high descent rate, and its airspeed was decreasing. The helicopter impacted terrain in a tail-low attitude. Subsequently, the tailboom separated from the fuselage, the helicopter rolled onto its right side, and the right landing skid folded under the fuselage.

Text from the NTSB. Open the NTSB docket for WPR12TA436 for the full record.