Buchanan Airport
Aircraft Accident/Incident Report

Concord, California 94520
Friday, April 30, 1999 9:17 PDT

The flight instructor and student were practicing straight-in autorotations with power recoveries. During the first four autorotations, the student was the primary manipulator of the controls. The student was initiating the flare too high and so the instructor told the student that they would do the next approach together with both of them on the controls. During the flare portion of the ensuing autorotation, the stinger struck the runway surface. The tail rotor then contacted the surface and the helicopter yawed 360 degrees to the right and came to rest approximately 100 feet where the tail rotor struck the runway. The main rotor severed the tail boom. The instructor reported that he believed that the student misinterpreted his instructions to mean that he (the instructor) would be making the primary control inputs, whereas, he had intended for the student to make control inputs to initiate the flare. He planned just to follow through on the controls to guide the student to flare a little lower than on the previous attempts. The flight instructor stated that the accident could have been prevented through 'better communication between student and instructor as to who is responsible for initiating a control input during all phases of flight and especially during critical phases.'

The inadequate supervision of the student pilot by the flight instructor during the practice autorotation, which resulted in a delayed flare and the tail rotor contacting the ground. A factor was a misinterpreted communication between the flight instructor and student.