What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
(.4) The co-owner/builder had been engaged in resetting the angle of attack (pitch angle) of the main rotor blades previous to the accident. Witnesses reported observing the gyrocopter depart to the south, proceed west, and then execute several oscillatory, rocking or pitching like maneuvers after which the aircraft entered a steep descent to the ground. Post-crash examination revealed that all eight of the main rotor blade pitch adjustment bolts were loose. Examination of the upper outboard shim plate of each blade attach bar revealed markings which clearly established a pitch bolt torque of 190 inch-pounds. Release of the main rotor blade pitch adjustment bolts would allow a rotor blade pitch change and subsequent loss of control. (-23) bolts used to secure blade angle was found loose.
As the FAA filed it
(.4) THE CO-OWNER/BUILDER HAD BEEN ENGAGED IN RESETTING THE ANGLE OF ATTACK (PITCH ANGLE) OF THE MAIN ROTOR BLADES PREVIOUS TO THE ACCIDENT. WITNESSES REPORTED OBSERVING THE GYROCOPTER DEPART TO THE SOUTH, PROCEED WEST, AND THEN EXECUTE SEVERAL OSCILLATORY, ROCKING OR PITCHING LIKE MANEUVERS AFTER WHICH THE AIRCRAFT ENTERED A STEEP DESCENT TO THE GROUND. POST-CRASH EXAMINATION REVEALED THAT ALL EIGHT OF THE MAIN ROTOR BLADE PITCH ADJUSTMENT BOLTS WERE LOOSE. EXAMINATION OF THE UPPER OUTBOARD SHIM PLATE OF EACH BLADE ATTACH BAR REVEALED MARKINGS WHICH CLEARLY ESTABLISHED A PITCH BOLT TORQUE OF 190 INCH-POUNDS. RELEASE OF THE MAIN ROTOR BLADE PITCH ADJUSTMENT BOLTS WOULD ALLOW A ROTOR BLADE PITCH CHANGE AND SUBSEQUENT LOSS OF CONTROL. (-23) BOLTS USED TO SECURE BLADE ANGLE WAS FOUND LOOSE.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.