The pilot was carrying out a "cleanup" swath run on a 50 acre potato crop which he had sprayed on the previous evening, but had not finished due to poor light. The cleanup run was conducted below a power line at right angles to the flight path and about eight metres above the crop. This power line was near another line which traversed the crop, and was at an angle of about 30 degrees to the flight path. The pilot was aware of the location of the second power line and had intended to fly over it after pulling up from the run under the first line. The run under the first line was completed, and when the pilot began to pull up, he noticed that the second line was closer than he had expected, and he decided to go under instead of over the line. During the manoeuvre, the right wing contacted the 3 strand 12 gauge steel wires, and the aircraft slid along the wires for some 200 metres before cartwheeling into the crop tail first. The aircraft then bounced upright and caught fire. The right wing had been severed by wire contact outboard of the wing strut supports prior to ground impact and the pilot had been sprayed with fuel. The pilot received burns to his right arm and left leg. He was wearing leather gloves, a short sleeved shirt and shorts under polyester and cotton overalls. He also wore a helmet. Despite the fact that the helmet was damaged during the accident sequence the pilot received no head injuries.