While manoeuvring to commence a clean-up spray run parallel to a power line, the helicopter collided with a spur line. A broken section of the cable struck and severed the tail boom, control was lost and the aircraft struck the ground 150 metres beyond the spur line. The pilot was aware of the presence of the spur line and had crossed it on a number of occasions during the operation. He elected to carry out a previously unplanned clean-up run to dispense the remaining chemical and temporarily overlooked the proximity of the wire. There was some evidence to indicate that the pilot was suffering from fatigue at the time of the accident.
