Circumstances:

There was a strong easterly wind blowing when the pilot landed. After landing he left the main rotor drive engaged and did not secure the collective control with the latch that was provided for that purpose. A sudden gust of wind caused the collective pitch, on the main rotor blades, to increase and the aircraft lifted off. The pilot regained control of the helicopter, but he was unable to avoid colliding with a tree.

After helping to herd cattle to a yard, the pilot turned the helicopter and accelerated away adjacent to a creek. The helicopter struck a powerline, which crossed the creek at right angles, and impacted the ground on its right side. One of the main rotor blades bounced backwards into the cabin and almost severed the pilot's right foot. The powerline was difficult to see against the background of the surrounding countryside. The pilot, who has no memory of the accident, was aware of the location of the powerline but now believes he must have temporarily forgotten about its presence.

The pilot said that he was flying the aircraft at 350 feet above the ground when the engine stopped suddenly. During the glide to earth, he carried out carburettor icing clearing procedures, switched the electric fuel pump on and attempted two engine starts, all to no avail. During the subsequent ground roll, the pilot was unable to avoid collisions with trees and an anthill. After the dust settled, he attempted an engine start which was successful. The reason for the engine stoppage has not been determined.

The pilot decided to carry out a circuit in order to check the performance of the engine. Because of the presence of a gusting 20 knot westerly wind, a higher than normal approach speed was flown. The pilot stated that he closed the throttle at about 50 feet agl and flared the aircraft. The subsequent landing was heavy, the aircraft bounced, the pilot moved the control column forward and the aircraft bounced a second time. On the third touch down the pilot reported that the tail struck the runway causing substantial damage to the tail area of the aircraft.

While returning to refuel at a mustering yard, the pilot attempted to move a bull from some trees. When this proved unsuccessful the pilot climbed to continue the flight to the yard. The engine began to run roughly and an approach to a clearing was made. Rotor rpm decayed as some trees were cleared and the pilot was unable to prevent a heavy landing. The helicopter bounced about two metres, the right skid collapsed and the main rotor struck the ground. Investigation revealed that the engine failed due to fuel exhaustion. The pilot's technique was to work on a set endurance from full tanks and not rely on the fuel gauge. At the previous refuelling he filled the tank to the filler neck, but the helicopter was parked on a slope which prevented approximately 20 percent of the tank's volume from being used, and reduced the endurance.

Circumstances:

The pilot reported that he made a normal approach to land on a large claypan. As he raised the nose to enter the hover prior to touching down, the tail rotor struck the ground, and the pilot was unable to prevent the aircraft from rolling over.

Because of obstructions around the intended landing area, the pilot carried out a downwind approach. As the pilot reduced the speed of the helicopter for landing it was caught by a sudden gust of wind. The helicopter sank, struck the ground and bounced before landing on the left skid which entered a depression in the ground resulting in the helicopter rolling over.

The aircraft departed Camden on the previous afternoon for a ferry flight to the Kununurra area, with an overnight stop near Eildon, Victoria. About 35 kilometres from Mildura the pilot reported that he was landing due to a vibration. After inspecting the aircraft he continued with the flight but later made a brief Mayday call. Witnesses reported that the engine was running intermittently before the helicopter landed heavily, tail-down, in a vineyard. A contaminant, sufficient in quantity to restrict the flow of fuel, was found in the fuel system filter. The source of the contaminant could not be identified, however an identical polyester material was found in the fuel filter of another new helicopter of the same type. It is probable that the material was present prior to the import of the helicopters. The fuel filters were not inspected prior to the first flight. The helicopter was being operated on super motor spirit at the time but it is considered unlikely, in this instance, to have been the major factor in the engine failure. Due to the pilot's incorrect diagnosis that the power surges were associated with a main rotor problem, he progressively opened the throttle in an attempt to maintain rotor rpm. This action combined with the momentary power surges, exacerbated control difficulties being experienced and resulted in a belated autorotative landing.

Following a normal touchdown and landing roll, the pilot commenced a left turn to backtrack along the runway to the parking area. During the turn the right main landing gear leg collapsed. An inspection of the gear leg revealed an incorrectly seated O-ring, which had allowed hydraulic pressure to bypass a section of the oleo. This resulted in the internal locking pins becoming unlatched prematurely when the assembly was subjected to side loads during the turn at the end of the runway. Records showed that the O-ring had recently been replaced, and it is likely that the distortion of the ring occurred during the oleo re-assembly process.

During a low-level photographic flight, the pilot made a shallow left turn at about 400 ft agl and a low forward speed. When he increased the rate of turn, the helicopter began a rapid turn to the right and the nose pitched up. The rotation continued for 3 to 4 turns during which the nose pitched up and down. The pilot had almost regained control when the helicopter struck the ground heavily on its skids and rolled onto its right side. The cause of the accident could not be conclusively determined but no mechanical defects were detected. The most probable cause was the operation of the helicopter in a mode that induced tail rotor stall and at a height that precluded a safe recovery following loss of control.