NTSB Identification: ANC12CA111
14 CFR Part 91: General Aviation
Accident occurred Tuesday, September 25, 2012 in Anchorage, AK
Probable Cause Approval Date: 12/19/2012
Aircraft: ROBINSON HELICOPTER R22 BETA II, registration: N4171J
Injuries: 2 Uninjured.
NTSB investigators used data provided by various entities, including, but not limited to, the Federal Aviation Administration and/or the operator and did not travel in support of this investigation to prepare this aircraft accident report.
The flight instructor was providing primary helicopter flight instruction to a student pilot. The instructor reported that while practicing a series of hovering autorotations, he inadvertently allowed the student pilot to drift to the left during the descent. The instructor then took control of the helicopter, applied right cyclic, and raised the collective slightly to level the helicopter and arrest the descent, but the helicopter started to descend with the right skid low. The instructor then added left cyclic and raised the collective further in an attempt to cushion the landing. The helicopter then drifted to the right as the right skid subsequently struck the ground. After touchdown, the helicopter’s skids slid over the asphalt surface before the right skid “caught,” the helicopter rolled to the right, and the main rotor blades struck the ground. The helicopter came to rest on its right side, sustaining substantial damage to the fuselage, tail boom, and main rotor drive system. The instructor reported that there were no preaccident mechanical problems with the helicopter that would have precluded normal operation. He also stated that the accident might have been avoided if he had taken corrective action sooner and with less input on the cyclic.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The flight instructor's inadequate supervision of the student pilot during a hovering autorotation, which resulted in a dynamic rollover. Full narrative available
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