The pilot was conducting agricultural spraying operations on a paddock 1400 metres long, with two sets of powerlines and a highway at one end. A person was deployed at each end of the paddock to provide tracking guidance to the pilot. As he approached the powerlines at spray height, the pilot observed the marker commence moving from the aircraft flight path, so he fixed his attention on the powerlines. Shortly afterwards the marker was struck on the left side of the head, by the left wing of the aircraft. The investigation revealed that the marker was not facing the aircraft at the time of the accident. He was experienced in the task, and the reason for his failure to maintain an adequate lookout, or to move out of the flight path of the aircraft, could not be established. However, it is considered possible that the marker may have turned to check for road traffic on the highway adjacent to the powerlines. In so doing, he turned his field of vision from the approaching aircraft.
