Robinson Helicopter R22 BETA N208WM accident near Spanish Fork, Utah

Probable cause

The flight instructor’s delayed remedial action and inadequate supervision during a practice autorotation, which resulted in a hard landing and rollover.

NTSB analysis

The flight instructor and student pilot were on a local training flight to practice autorotations. The flight instructor reported that the student entered a 180-degree autorotation at an altitude of about 5,200 feet mean sea level at 65 knots. The student started the maneuver by initiating a descending "hard" right turn. Shortly after, the low rotor light illuminated, and the low rotor horn sounded. In response, the flight instructor assisted the student through the maneuver, and they added left cyclic and decreased the airspeed and sink rate. Although the rpm horn stopped, the helicopter's sink rate was excessive, so the flight instructor took control of the helicopter. He reported that the rotor seemed as if it was not responding to inputs and that the helicopter's sink rate was "pretty fast." The helicopter lost considerable altitude in the turn, and the flight instructor rolled on the throttle and flared in the short amount of distance between the helicopter and the ground. The helicopter subsequently touched down hard and rolled over. The flight instructor reported no preimpact mechanical malfunctions or failures with the helicopter that would have precluded normal operation.

Text from the NTSB. Open the NTSB docket for WPR12LA362 for the full record.