Robinson Helicopter R22 BETA N74815 accident near Chandler, Arizona

Probable cause

The certified flight instructor's inadequate supervision of the student pilot during a hover demonstration and his subsequent loss of helicopter control that resulted in a dynamic rollover.

NTSB analysis

The purpose of the flight was for the certified flight instructor (CFI) to demonstrate the helicopter to a prospective student who had no prior helicopter flying experience. They had just performed an hour of uneventful flight and decided to practice hover maneuvers over a turf area adjacent to the airport helipad. The CFI briefed the student on the sensitivity of the helicopter controls during a hover and then passed over the controls to the student. The student unsuccessfully attempted to perform a hover and the CFI then regained control. He elected to let the student try to hover again, and as he relinquished control, the helicopter rolled to the left. The CFI attempted to correct the deviation; however, during recovery the low rotor rpm warning horn sounded. He increased the throttle, but the skid made contact with the ground and the helicopter rolled onto its side. The helicopter sustained substantial damage to the rotor system and gearbox during the accident sequence.

Text from the NTSB. Open the NTSB docket for WPR09CA173 for the full record.