Bell Helicopter Textron 206L-1 N2072M accident near Grand Canyon, Arizona

Probable cause

The failure of the flight instructor and the pilot receiving instruction to recognize before entering the flare that the wind had shifted to a tailwind and terminate the practice autorotation.

NTSB analysis

The flight instructor reported that she and the pilot receiving instruction were practicing autorotations. During an autorotation involving a right 180-degree turn, the flight instructor announced that the throttle was coming on, and then announced when full throttle was on. The pilot then started to level the helicopter. Because the wind had shifted to a tailwind during the maneuver, the pilot was forced to flare harder and use more cyclic control than expected. The flight instructor realized that completing a power recovery from the autorotation was going to result in an overtorque condition, took over control, and landed the helicopter. During the landing, the tailboom was substantially damaged. The flight instructor reported no preimpact mechanical malfunctions or failures with the airframe or engine that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for WPR13CA206 for the full record.