The pilot was spraying a crop of potatoes. The rows in the paddock ran north-south and there was a powerline running from just outside the paddock at the south-western corner to about one swath width inside the paddock at the north-western corner. Spraying of the bulk of the paddock had been completed, with runs aligned with the rows. The runs were shortened on the western edge to avoid flying under the powerline. There was an easterly drift in the breeze, which the pilot assessed as 2 to 3 knots. He started a cleanup run along the western edge tracking from north to south, intending to use the drift to carry the spray under the wires into the corner of the paddock. The pilot selected an aiming point at the far end of the paddock so that the helicopter would fly parallel to the powerline. During the run the helicopter became entangled in the wires and crashed before catching fire. The pilot had made no allowance for drift in selecting the aiming point. This accident was not the subject of an on-site investigation and information on the occurrence was provided by the pilot.