Accident Details
A helicopter performing a practice autorotation rolled onto its side and came to rest on its right side after a wind shift altered the expected conditions. The aircraft had been positioned facing into the wind based on the instructor's assessment of direction. During the descent, the flare was initiated at approximately 40 feet above ground level. Despite the addition of throttle and raising the collective, the helicopter continued descending and settled toward the ground. The aft portion of the skids first contacted the sandy surface, and the helicopter continued forward with minimal airspeed. It then pivoted about the right skid, rolled over, and came to rest on its right side.
Instructor's Observations
The instructor stated that before the maneuver, he determined wind direction by comparing indicated airspeed to the GPS-displayed speed and by observing dust behind a tractor operating in a field. Both indicators confirmed the wind was from the east. After the student demonstrated several maneuvers, the instructor decided to practice autorotations and again verified the wind as easterly. Following the accident, upon egressing, the instructor noted that the wind had changed direction during the practice autorotation, resulting in the helicopter performing the maneuver with a tailwind. He reported no mechanical malfunctions or failures prior to impact.
Witness Account
Another helicopter pilot practicing in the vicinity stated that he observed a wind shift around the time of the accident.