NTSB Identification: LAX07CA247.
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Accident occurred Friday, August 10, 2007 in Chino, CA
Probable Cause Approval Date: 10/31/2007
Aircraft: Robinson R22 Beta, registration: N10QD
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 helicopter landed hard during a practice autorotation maneuver. Following the private pilot's unsuccessful attempt at a 180-degree autorotation, the certificated flight instructor instructed him to perform the maneuver again. The private pilot entered the autorotation and as the descent proceeded, he utilized the collective to maintain the rotor revolutions per minute (rpm) within the normal operating range. Through the turn, the instructor noticed that the helicopter was gradually assuming a nose-low attitude. The instructor advised the student to level the helicopter and continue to maneuver through the turn. The instructor subsequently assumed authority of the flight controls and the helicopter continued to descend through 100 feet above ground level (agl). The helicopter was at an airspeed of 40 knots and vibrating with the low rotor warning horn sounding when the instructor leveled the helicopter as it simultaneously contacted the ground. The helicopter touched down hard and slid on its belly to the edge of the runway surface. The instructor reported no mechanical malfunctions or failures with the airframe or engine prior to the accident. He stated that the accident may have been prevented if he had assumed authority of the controls earlier in the maneuver.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The private pilot's failure to maintain the proper airspeed and main rotor rpm, which resulted in a high rate of descent and subsequent hard landing. Also causal was the certificated flight instructor's delayed remedial action. Full narrative available
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