The pilot had just completed a low-level turn to down wind when the helicopter began to sink. He applied power and collective control but was unable to arrest the sink and the tail rotor struck the ground. The helicopter then rotated 3-4 turns to the right and dropped heavily onto its skids. The pilot shut down the engine. Fire broke out and the passenger was struck by the still rotating main rotor as he ran around the tail to reach the boom-mounted fire extinguisher. The investigation did not reveal any fault with the aircraft that might have contributed to the accident. The reason for the helicopter sinking after the turn could not be positively determined.
