The pilot was conducting spraying operations over a millett crop which was approximately 1.5 metres high. Towards the end of the spray run, the aircraft flew under two wires which were about 5.6 metres above the ground. Weather conditions were ideal with high overcast cloud and a light southerly wind. On the second spray run, the aircraft struck the powerlines. The aircraft's wire deflector cable was broken and the wires then struck the vertical fin, one 50 millimetres from the top and the second 150 millimetres from the top. The wires then tore the tail fin off the aircraft, leaving the rudder trailing by its control cables. The aircraft was seen to pull up abruptly to a height of approximately 150 feet, turn left and head toward open paddocks one kilometre away. Shortly after, it descended rapidly into a crop about 300 metres short of open paddocks, coming to rest 19 metres from initial impact. Engineering examinations found that the elevators had been fouled by the trailing rudder. It is probable that the pilot experienced difficulties with elevator control, resulting in loss of control of the aircraft.