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Summary

Summary

The aircraft took off from runway 23 at Ballarat for a test flight. The takeoff was witnessed by many operations and maintenance personnel who work on the airfield.

Witnesses advised that shortly after takeoff they heard some loud bangs from the engine, which some described as backfiring, and then engine noise ceased. They estimated that the aircraft was 300 ft above the ground at this point. The aircraft then turned steeply to the left without much loss of height. After turning through approximately 180 degrees and levelling, the nose dropped and the aircraft spiralled steeply towards the ground. Immediately before impact, the engine surged to high power. Impact was

approximately 250 m beyond the end of the runway and 206 m to the left of the extended centerline.

The aircraft was destroyed by impact forces and fire. The impact was not survivable.

The terrain beyond the end of the runway was flat farming land with dispersed buildings and trees, but provided suitable forced landing sites. Extensive fencing was the main hazard to a forced landing in this area.

The pilot of the aircraft was a licensed aircraft maintenance engineer (LAME) and his passenger was an apprenticed aircraft maintenance engineer. Both worked at the aerodrome. The pilot was also the owner of the aircraft, having restored it to flying condition approximately 5 years prior to the accident.

The pilot commenced flying in 1972. He flew regularly and in December 1990 was issued with a rating to fly at night under visual flight rules. In December 1992, he obtained his commercial pilot licence. At the time of the accident, he had flown approximately 890 hours, 240 of which were in the accident aircraft.

Persons who worked with the pilot at the airfield advised that in November 1995, 3 months before the accident, the aircraft was flown interstate by another pilot. During that flight, the engine was reported to have hesitated, run rough and had reduced power available. The aircraft was examined by a LAME but no fault was found. After the aircraft returned to Ballarat, the owner removed the engine-fuel nozzles and fuel distributor valve for testing. The test was satisfactory and the owner reinstalled the components.

The aircraft operated until 20 February 1996 when, as a result of further rough running and reports of the engine cutting out on takeoff, the pilot removed the engine-driven fuel pump, the fuel control unit, and the throttle assembly for testing. The bushes on the mixture shaft of the fuel control unit were replaced, and some minor lint contamination was cleaned from the fuel control unit filter; otherwise, the units were found to be serviceable.

The pilot reinstalled the units and, on 29 February, the day of the accident, carried out engine test runs. After some initial setting up problems, the engine was reported to have operated satisfactorily, and the pilot was observed to taxi out to the runway and take off. The takeoff was reported to be normal until the backfiring that preceded the accident.

It was determined that there was sufficient fuel on the aircraft for the flight as it had only been flown for about 1 hour since having the main tanks filled. The investigation was able to determine that at the time of the main impact, the fuel selector was selected to the right main fuel tank. The investigation could not determine the distribution of the fuel within the tanks, nor the exact quantity on board.

No abnormalities were found during the examination of the engine and components except that five pebbles were discovered in the cockpit- mounted fuel selector. Three were located in three of the five fuel passages in the strainer body. The other two were loose in the cavity between the main rotor and the strainer body and were able to sit over and partially block the fuel-feed passage.

The investigation is to be continued by the Victoria Police.

 
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