Incident Overview
A Robinson R22 helicopter, conducting autorotation training, was involved in an accident when it struck the ground and rolled onto its right side. The flight was being performed with an instructor and a trainee pilot.
Sequence of Events
According to reports from both pilots, the training maneuver was a 180-degree autorotation to touchdown, initiated from an entry airspeed of 70 knots and an altitude of 300 feet above ground level (AGL). The instructor noted that approximately halfway through the turn, the helicopter's indicated airspeed was 65 knots, which corresponds to the maximum glide distance speed as specified in the R22 Pilot's Operating Handbook, and rotor RPM was within normal operating range.
The trainee reported that after establishing the appropriate turn rate, rotor RPM remained normal, but airspeed had decreased to about 50 knots. Shortly thereafter, the trainee observed that "the rate of descent appeared to be higher than normal and the ground closer than expected." The instructor similarly noted a descent rate "greater than normal for our proximity to the ground" as they were about to roll out of the turn.
Accident Sequence
Both pilots stated that they attempted to recover from the situation, but the helicopter subsequently struck the ground and came to rest on its right side.
Post-Accident Examination
A post-accident examination of the helicopter found no evidence of any pre-impact mechanical malfunctions or failures that could have contributed to the accident.