Accident Details
A helicopter operating on a positioning flight suffered an in-flight breakup while crossing a line of trees between two cleared areas. The wreckage was scattered over an area approximately 300 yards in length along a heading of 340 degrees. At the southeastern end of the debris field, pieces from the left spray boom and the main rotor aerodynamic fairing were found. Further northwest, various components from the left side of the helicopter, including the left spray boom and the tail rotor, were recovered.
The main rotor and main rotor hub were located about 120 yards to the right of the wreckage path. The fuselage, engine, and transmission were found approximately 240 yards northwest of the initial wreckage pieces.
Wreckage Examination
Examination of the wreckage revealed that the main rotor system had separated due to mast bumping. There was evidence that the left spray boom had contacted the main rotor blades during flight. All fractures of the spray boom, the steel truss, and associated lugs indicated overload failure in an aft and upward direction.
Findings
The investigation determined that the spray assembly and boom had not been installed in accordance with FAR Part 23.