Incident Overview
A Kawasaki Vertol KV-107 II rotorcraft was involved in an accident while conducting a non-mandatory test flight. The flight was requested by the pilot-in-command (PIC) to adjust the rotorcraft's engine synchronization system. The test was performed with a bucket and a 150-foot long line attached to facilitate the procedure.
Witness Observations
According to witnesses, the rotorcraft was observed at altitudes between 300 and 1,000 feet. As it began to climb, it started to pitch and roll before descending rapidly. Several witnesses noted that the bucket was horizontal to the rotorcraft and appeared to be caught in one of the rotors.
Impact and Wreckage
The aircraft impacted on its right side, remaining intact except for its rotor blades. Two of the three forward rotor blades were located 600 to 900 feet from the ground impact site. The third forward rotor blade was broken in half; its outboard section was found at the impact site, while the inboard half was approximately 100 feet away. All three aft rotor blades were found close together, about 400 feet from the primary impact site. All six blades separated from their root sections at similar points. A post-crash fire destroyed a significant portion of the rotorcraft.
Examination Findings
Post-crash examination established control continuity from the cockpit through the control closet to all associated hydraulic actuators, as well as continuity of the entire synchronization drive shafting. Disassembly and inspection of major components revealed no evidence of fatigue propagation, disconnects, or other time-dependent failure mechanisms. X-ray examination and disassembly of all hydraulic actuators showed no blockage or jamming. The engines were examined and disassembled; the gas generator speed range for both engines was determined to be between 64.3% and 69.7%, approximately 10% above ground idle.
Long Line Interaction
Evidence indicated that the long line cable contacted the nose gear strut, an aft strut, the forward left side of the fuselage, the forward rotor head rain shield, and all three forward rotor blades. It could not be determined whether the cable-to-rotor interaction was an initiating event or the result of a prior occurrence that allowed the cable to become entangled.
Crew Information
The PIC had over 1,630 hours of V-107 rotorcraft time, with more than 670 hours logged as PIC time. The co-pilot had over 150 hours of V-107 rotorcraft time, none of which was PIC time.