On the morning of 7 February 2004, the pilot of a Piper Aircraft Corporation PA-28R-200 Arrow, VH-TRZ, conducted a private sightseeing flight over Lake Eildon in Victoria with three passengers onboard. At about 1135 ESuT, witnesses observed the aircraft strike a power cable over the lake. The cable was one of a group of six cables that formed a power line linking Kiewa in north-east Victoria to Melbourne. Each cable was 30.8 mm in diameter, and transmitted 220,000 volts of electricity. The power line was depicted on the Melbourne World Aeronautical Chart, and spanned Lake Eildon between Mt Enterprise and Mount Pinniger. The power line was not fitted with marker devices, and nor was it required to be. The span was 2,222 m in length, and the northern and southern support towers were respectively 1,076 ft and 781 ft above the water level of the lake. The aircraft struck the power cable at about the lowest point of the span, which was about 133 ft above the water level of Lake Eildon. The water level of the lake was 266.53 m above Australian Height Datum on the day of the accident. That was equivalent to 875 ft above mean sea level (AMSL).
The aircraft approached the power line in a south-easterly direction, and the sun's position and elevation at the time were unlikely to have caused the pilot difficulty in observing the cables, which lay at right angles to the aircraft's flight path. Witnesses who observed the aircraft before it struck the cable reported the aircraft had appeared to be operating normally. A number of those witnesses reported that their attention had been drawn to the aircraft because of its low height above the surface of the lake.
The force of the wirestrike dislodged the left wing of the aircraft, and the aircraft descended out of control and impacted the water about 165 m beyond and to the southeast of the cable that was struck. The aircraft was substantially destroyed because of the wirestrike and the subsequent impact with the water. The four aircraft occupants were fatally injured by impact forces when the aircraft impacted the water. The body of the pilot was not located.
The aircraft had valid certificates of registration and airworthiness. The pilot held a Private Pilot (Aeroplane) Licence and was endorsed to fly the aircraft type. He held a current Class 2 medical certificate. The pilot required vision correction, and his wife reported that he was wearing contact lenses on the day of the accident. There were no known physiological or psychological factors that may have affected the pilot's performance.
There was no evidence that environmental, mechanical, operational or other factors contributed to the circumstances of the accident.
Civil Aviation Regulations specify that an aircraft, when not flying over a city, town or populous area, must not fly lower than 500 ft above the highest point of the terrain, and any object on it, within a radius of 600 metres. The aircraft therefore should not have been flown at a height of 133 ft over the surface of the lake. The investigation could not determine why the pilot descended the aircraft to an unsafe height.