Incident Details
A flight instructor (CFI) and a student pilot were engaged in an instructional flight. The student practiced hovering autorotations over a river bed area that was clear, moist, and sandy.
Sequence of Events
The student began an autorotation from a hover at 3 feet above ground level. At approximately 1 foot above the ground, the helicopter started to drift leftward. The CFI took control and applied right cyclic input. Rotor rpm continued to decay during this time. The right cyclic input did not stop the accelerating leftward movement. The left skid subsequently contacted the sandy terrain, leading to a dynamic rollover. The helicopter rolled onto its left side.
Weather Conditions
Wind at the accident site was estimated from the west at about 10 knots.
Conclusion
The accident involved a dynamic rollover during a hover autorotation training maneuver.