The pilot had completed a pre-flight inspection, when he received a message to the effect that there was an unfamiliar vehicle in the vicinity of a new farm piggery, about 2 km from the strip. He boarded the aircraft, which shortly afterwards was seen to take-off and fly at low level towards the piggery. A farm employee at the piggery observed the aircraft approaching in straight and level flight and with normal engine noise. The aircraft then began to turn to the left, but struck a recently erected single wire power line at a height of 23 feet above the ground. The left wing tip and one propeller blade were severed and the aircraft cartwheeled to the ground. No defect or malfunction was subsequently discovered which might have affected the pilot's ability to safely control the aircraft. It was considered probable that the pilot was concentrating on locating and identifying the vehicle near the piggery, to the extent that he overlooked the presence of the power line. Notwithstanding the above, the reason the pilot chose to fly at such a low height could not be determined.