The disconnection of the tail rotor drive shaft and subsequent lack of tail rotor control. Contributing factors were the worn drive shaft splines and the pilots' failure to apply collective on the touchdown resulting in a hard landing and subsequent roll over.

Improper repair of a previous crack in the blue main rotor blade by unknown persons; improper inspection of the main rotor blades by maintenance personnel, following a reported vibration problem; and subsequent failure of the main rotor blade, which resulted in an uncontrolled collision with the terrain.