The rotor was being pre-rotated in preparation for departure. The pilot recalled seeing 200 rpm but shortly thereafter noticed the rotor rpm indication had dropped to zero. Concerned that the rotors might now be rotating below 200 rpm he decided to attempt to increase the rotor rpm by commencing a takeoff roll. At approximately 30 kt the cyclic control moved violently and was wrenched from the pilot’s grasp. The aircraft pitched up, yawed left and rolled left before falling upright and sliding along the runway.
It is likely that the aircraft encountered a blade sailing event as the airspeed increased and the rapid movement of the rotor disc forced the controls from the pilots grasp.
Download glossary of abbreviations:
Glossary of abbreviations
Published 10 January 2019