What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Pilot was attempting to further phase I requirements following certification. During flight the aircraft started to vibrate. The pilot turned and started to descend in an effort to land in an opening when he heard a loud pop sound followed by a loss of the tail rotor authority and aircraft started to counter rotate. Aircraft struck the ground and rolled upon its left side causing substantial damage and serious injury to the pilot. The main rotors were destroyed and there was no damage to the tail rotor blades. Investigation revealed the flight control continuity was intact. The tail rotor quill did not rotate with the main rotor blades upon inspection. Teardown analysis revealed the tail rotor pinion sheared.
As the FAA filed it
PILOT WAS ATTEMPTING TO FURTHER PHASE I REQUIREMENTS FOLLOWING CERTIFICATION. DURING FLIGHT THE AIRCRAFT STARTED TO VIBRATE. THE PILOT TURNED AND STARTED TO DESCEND IN AN EFFORT TO LAND IN AN OPENING WHEN HE HEARD A LOUD POP SOUND FOLLOWED BY A LOSS OF THE TAIL ROTOR AUTHORITY AND AIRCRAFT STARTED TO COUNTER ROTATE. AIRCRAFT STRUCK THE GROUND AND ROLLED UPON ITS LEFT SIDE CAUSING SUBSTANTIAL DAMAGE AND SERIOUS INJURY TO THE PILOT. THE MAIN ROTORS WERE DESTROYED AND THERE WAS NO DAMAGE TO THE TAIL ROTOR BLADES. INVESTIGATION REVEALED THE FLIGHT CONTROL CONTINUITY WAS INTACT. THE TAIL ROTOR QUILL DID NOT ROTATE WITH THE MAIN ROTOR BLADES UPON INSPECTION. TEARDOWN ANALYSIS REVEALED THE TAIL ROTOR PINION SHEARED.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.