Primary finding
Probable cause
The flight instructor's delayed reaction in taking control of the helicopter during a student pilot's loss of control while landing.
Investigator assessment
Analysis narrative
During an instructional flight, the student was practicing "hydraulic off" landings. The flight instructor (CFI) stated that he had to take control of the helicopter during the landing, due to the student pilot's loss of control of the helicopter's yaw and pitch. The CFI was unable to prevent the helicopter from rotating and it inadvertently struck the ground, which resulted in substantial damage to the tail boom and main rotor blades. The CFI reported no preexisting mechanical malfunctions or failures with the helicopter that would have precluded normal operation.
Source record
Factual narrative
During an instructional flight, the student was practicing "hydraulic off" landings. The Certified Flight Instructor (CFI) stated that he had to take control of the helicopter during the landing, due to the student pilot's loss of control of the helicopter's yaw and pitch. The CFI was unable to prevent the helicopter from rotating and it inadvertently struck the ground, which resulted in substantial damage to the tail boom and main rotor blades. The CFI reported no preexisting mechanical malfunctions or failures with the helicopter that would have precluded normal operation.