A group of five firemen had finished a task in a fire fighting area and were to be winched out from steeply sloping terrain. The helicopter hovered at about 30 feet while the first two men attached themselves to the dual winch hook. They were then raised to the aircraft, following which the next fireman was also lifted. The remaining two men then attached themselves to the hook. The operation proceeded normally until the men were close to the skids of the helicopter. At this point the winch cable broke and the men fell to the ground. An inspection of the cable revealed that it had come off one of the pulleys of the hoist and become jammed. Fraying of the cable had occurred and it had finally failed in overload at a point some 4 metres from the hook. A number of kinks were found in the cable, possibly resulting from the operator's maintenance and inspection procedures. Such cable twisting would have increased the possibility of the cable riding over the edge of the pulley, particularly when the cable was not under tension. Such a situation would occur when extra cable was paid out to assist with the attachment of the cable to a person's lifting harness. The length of frayed cable was consistent with this sequence happening on the hoist on which the accident occurred.

Circumstances:

The aircraft was cruising at 2500 feet above ground level when the engine suddenly stopped. The pilot carried out a forced landing in heavy scrub, during which the aircraft was extensively damaged. The pilot declined to provide any information. However, other information obtained indicates that the right wing tank contained 90 litres of fuel and the left wing tank unusable fuel only. The contents of the fuel lines indicated that the engine had stopped as a result of fuel starvation. No defects were found which may have contributed to the accident.

The aircraft was the first of a group of four aircraft being used to return staff to an alluvial gold mine after a weekend break. The weather in the area of the destination was not suitable for a visual arrival and the aircraft was initially held for several minutes in an area five kilometres to the south of the strip, awaiting an improvement in the weather. The aircraft was then flown towards the strip and the pilot reported to a following aircraft that there had been a lot of rain and that the strip looked wet. He also advised that he intended to carry out a precautionary circuit and check if it was safe to land. No further transmissions were received from VH-TLQ. The wreckage of the aircraft was subsequently found burning in a river valley, 300 metres west of the threshold of runway 34. Surviving passengers stated that the aircraft struck trees shortly before impact. There were no ground witnesses. The aircraft had impacted the ground in a steep nose down left wing low attitude, at a low forward speed, then cartwheeled up rising ground before coming to rest inverted, 42 metres from the point of impact. The cabin area was destroyed by an ensuing fire. An inspection of wreckage did not reveal any mechanical defect or failure that could have contributed to the accident. The reasons for the apparent loss of control of the aircraft could not be determined.

The aircraft arrived in the circuit area in the late afternoon. The pilot assessed that the prevailing wind would make it necessary to land into the sun on Strip 29. He overflew the strip and carried out a right hand circuit intending to touch down on the left side of the strip, to allow for the crosswind. After touchdown, the pilot looked out of the left window in an attempt to keep the aircraft aligned with the strip. However, he did not see three half 200 litre steel drums that were located 14 metres in from the left side of the strip and the left mainwheel struck one of these drums. The left maingear folded and the aircraft slewed to the left and became entangled in the perimeter fence before coming to rest. The steel drums encroached on the strip landing area. The pilot was not aware of their location before landing although the drums could be readily seen from circuit altitude. The non-standard circuit pattern, the decision to land on the left side of the strip and the sunglare all contributed to the accident.

While cruising at 3000 feet, the aircraft suddenly encountered strong turbulence. Almost immediately afterwards, the engine commenced to run roughly and the pilot was unable to maintain height. He intended to carry out a precautionary landing on a freeway, but then sighted a strip nearby and positioned the aircraft for a left circuit. He subsequently advised that he elected not to lower the landing gear because he considered that the aircraft would have rolled beyond the end of the 550 metres long sealed strip. The aircraft touched down some 350 metres beyond the threshold and slid for 134 metres before coming to rest. Investigation disclosed that the exhaust valve guide clearances in five cylinders were less than the minimum specified by the engine manufacturer. The engine power loss resulted when an exhaust valve in one cylinder became jammed in the valve guide by a build-up of carbon deposits. The loss of power occurred over unfavourable terrain, and the pilot had been committed to a downwind approach to the strip selected for the forced landing.

The pilot had only recently arrived in the area and had not operated from this strip previously. On his first take-off from the strip he decided to employ a short field technique and lifted the aircraft off the ground at 50 knots. The aircraft became airborne after a ground roll of about 250 metres but after travelling a further 110 metres the wingtip struck the ground, the aircraft landed heavily and ran off the side of the strip. The pilot continued with the attempted take-off and the aircraft travelled a further 325 metres before the take-off was abandoned when the aircraft struck trees. The Pilot's Operating Handbook gives the climb speed after a short field takeoff as 57 knots. The prevailing wind at the time was a crosswind from the right and the pilot believes he may have encountered some tailwind component during the take-off. This combined with a lower than recommended climb speed probably resulted in the aircraft stalling before contacting the ground. After the aircraft had run off the strip it was travelling downwind over soft ground and thus would have required a higher groundspeed than that probably expected by the pilot before it became airborne.

As the helicopter was cruising at 1000 feet agl, the engine suffered a complete loss of power. An autorotation was commenced and the pilot headed the aircraft towards a clear area, to land. At the completion of the landing flare, the heel of the skids dug into the ground and the main rotor blades struck the tail boom. An examination of the engine determined that the fuel regulator diaphram stem had suffered a fatigue failure. This allowed the diaphram to shut off fuel flow to the engine. The pilot elected to carry out a zero speed touch down because he believed that the terrain was unsuitable for a run-on landing, but he misjudged the landing flare.

The aircraft was the only known one of its type in the country, and had been imported by the pilot in 1982. It had not been flown since April 1984. The pilot intended to ferry the aircraft to a neighbouring strip, but about 7 minutes after DEPARTURE the aircraft was seen to turn back. Approaching the DEPARTURE point, the aircraft suddenly pitched up, and shortly afterwards the left wing failed. The pilot attempted to use the recovery parachute, but this became entangled in the rotating propeller and the aircraft fell to the ground. It was likely that the pilot had abandoned his intended flight because of turbulence in the area. The left wing of the aircraft had folded in flight following failure of the lift strut, and the aircraft was in an extreme attitude when the recovery parachute was deployed. The pilot was not a member of the Australian Ultralight Federation, and had not contacted any local members for guidance or assistance prior to the flight.

After takeoff, at about 100 feet above ground level, the engine began to surge. The pilot changed the fuel tank selection and operated the auxiliary fuel boost pump but the engine did not regain power. The pilot then manoeuvred the aircraft in an attempt to find a clear area to land. However, he was unsuccessful and the aircraft collided with trees at a low forward speed. During the impact sequence a fire broke out and almost completely consumed the cabin area and the inboard sections of the wings. Despite the extensive fire damage, small amounts of water and rust were found throughout the fuel system. No other defects were discovered which might have explained the reported engine malfunction, and it was likely that the power loss was caused by water contamination of the fuel. The method by which the water entered the fuel tanks was not established, but may have resulted from condensation and/or the ingress of rain water through the tank caps. The water had not been detected by the pilot during his pre-flight inspection.

Prior to attempting the landing the pilot carried out an aerial inspection of the strip. The aircraft touched down on a gravel road leading to the strip, however, the ground track of the aircraft was effected by a windrow along the side of the road and the pilot was unable to control the aircraft. The pilot applied power to carry out a go-around, but the right main wheel struck a car tyre, which was used to mark the strip threshold, causing the aircraft to veer to the left towards a fence. The pilot managed to manoeuvre the aircraft over the fence but it struck the ground, wingtip first, in an adjacent paddock. The majority of the surface of the strip within the boundry markers consisted of a four metre wide road and the pilot was apprehensive about its use. However, following the conduct of a circuit at the strip by the aircraft's owner, the pilot decided to use the strip as the passengers were waiting to depart for Geraldton. On the return flight the pilot was apprehensive about the landing, but decided not to divert to a nearby airfield because of the likelihood of the passengers experiencing subsequent transportation delays. To increase the landing distance available, the pilot decided to land short of the threshold marked by the tyres at the edge of the road. Once on the ground the pilot's view of the tyres was restricted by long grass.