Circumstances:

On the day before the accident, the pilot had been mustering cattle on Cukadoo Station which is the neighbouring property to Nithsdale. The owner of Cukadoo had accompanied the pilot during the mustering operation, which was close to the accident site. The pilot had flown over a single-wire powerline several times during the day and remarked that he would have to be careful of the powerlines. This was a spur line which joined the main line (which the helicopter struck) at right angles, approximately 1.4 km from the accident site. Late in the afternoon the pilot flew to Mt Isa, where he remained overnight, with the intention of returning to his own property in the Northern Territory the next day. During the evening, he had telephoned the owner of Mt Ryde Station west of Longreach, where he had cattle on agistment. The cattle were being driven to another property in the Northern Territory recently purchased by the pilot. The pilot was told that some of the cattle were still at Mt Ryde, and he became very concerned. The pilot said he would come down to Mt Ryde to resolve the matter. At about 0930 the next morning the sound of a helicopter was heard passing near Cukadoo homestead 200 km southeast of Mt Isa at very low altitude. Initially it appeared that the helicopter was going to land there, but the noise receded towards the southeast without the helicopter being sighted. About 5 minutes later the electricity supply to the homestead failed. Later in the day the wreckage of the helicopter was discovered by linesmen who were investigating the cause of the electrical supply failure. The helicopter had struck the Single Wire Earth Return (SWER) 19 Kilovolt line 9.5 km southeast of Cukadoo homestead. The wire was struck approximately mid-span between supporting poles 400 m apart, and about 7.5 m above ground level. The line was aligned approximately at right angles to the south-easterly flight path of the helicopter. The wire impacted the nose of the helicopter at about floor level, causing the helicopter to pitch nose-down, and the main rotor to sever the tail boom. The helicopter then impacted the ground and burned. Wreckage distribution indicated that the helicopter may have been at cruising speed at the time of impact with the wire. The location of the accident was approximately on track between Mt Isa and Mt Ryde. The powerline was in flat open grassland which could cause the poles to blend with the background. At the time of the accident the weather was fine, but there was a 10 to 15 knot south-easterly wind, and it appears that the pilot may have been flying at low level in an attempt to conserve fuel. There were no mechanical defects discovered which may have led to the development of the accident.

Significant Factors:

The following factors were considered relevant to the development of the accident:

1. The helicopter was being flown at an extremely low height.

2. The pilot failed to see or avoid the powerline.

The aircraft was being used for dual instruction when the attention of witnesses standing on the beach was drawn to it by a loud report. The aircraft was observed to be falling almost vertically, with both wings trailing, from an altitude of about 150 feet. It impacted in the sea about 100 metres from the shore and disappeared. Inspection of the wreckage found that the design of the control system was such that with certain control inputs the rear control cables could foul the propeller. On this occasion the left rear control cable had been severed by the propeller and this had resulted in the total collapse of the wing.

Circumstances:

The pilot was flying his first period of solo practice forced landings. Circuits were flown at 1000 feet above ground level (agl), and the landings were terminated using the introduction of power from about 100 agl, without making a touchdown. On the fifth circuit, the pilot noticed an engine vibration commence at about 500 feet agl and worsen as the approach was continued. At about 60 feet agl, the pilot attempted to introduce power but obtained no response from the engine. Further attempts to obtain engine power were made, without success, as the pilot continued with the forced landing. The touchdown occurred with little rate of descent or forward speed; however, the aircraft was moving sideways slightly and rolled on its side. Other pilots had previously reported intermittent rough engine running. The reason for the rough running on this occasion was undetermined; however, the engine was close to the end of its overhaul life. The piston rings and valves were in poor condition but operating within limits.

Significant Factors:

The following factors were considered relevant to the development of the accident:

1. The engine lost power for undetermined reason.

2. The pilot did not have the helicopter aligned with the direction of travel at touchdown

Circumstances:

The helicopter was to be used to move cattle from one paddock to another on the property. Staff expected that the aircraft would return to the refuelling point around 1100 hours local time. A search was commenced at about this time. The wreckage was located in the mustering paddock at about 1230 hours. Examination of the wreckage indicated that the tail boom had been moved in an anticlockwise direction into the top of an 11-metre-high gum tree. The tail rotor blades struck the tree trunk, which was 25 millimetres in diameter, and part of one blade broke off. Out-of-balance and still rotating the entire tail rotor and stabilizing fins separated from the tail boom. The main body of the helicopter then struck the ground at a very high rate of descent. There was no horizontal speed, yawing or bank at the time of impact. The pilot was unable to remember the accident circumstances and there were no other witnesses.

Significant Factors:

The following factors were considered relevant to the development of the accident:

1. The area contained occasional trees significantly higher than the surrounding bush.

2. The tail rotor struck the top of a tree for reason/s that could not be determined.

The aircraft had been engaged in spraying a carrot crop. The pilot reported that as the aircraft descended for a spray run, the engine failed completely. The pilot made a forced landing in the crop. The gear was torn off and the aircraft came to rest 30 metres from initial touchdown. The pilot reported that the engine failure had been caused by fuel exhaustion. He reported that he had been distracted at his last stop. The hopper had been loaded but he had failed to refuel the aircraft. This accident was not the subject of an on-site investigation.

The pilot had commenced superspreading operations at about midday, and was returning to his base strip at the completion of the day's activities. He was landing towards the west. The strip slopes up 4` to the west. The pilot reported that he had not been aware until the flare that he was landing with a tailwind component, as there had been a westerly component in his operations area. He touched down some distance along the strip. Due to looking into the setting sun, he misjudged the distance remaining and was slow to apply braking. When it was obvious that the aircraft would not stop before the boundary fence, he turned the aircraft to the left to minimise damage. The outer right wing struck a fence post.

The aircraft was taking off towards the north, into an estimated 8-10 knot headwind, from a strip surrounded by light scrub and trees. Shortly after lift-off the pilot said the aircraft began to sink, the stall warning horn sounded and the airspeed rapidly decreased by at least 10 knots. He said he considered the aircraft would not be able to outclimb trees ahead and therefore aborted the take-off. The aircraft was placed back onto the strip but could not be prevented from overrunning the end and colliding with small trees. The circumstances of the accident are considered to be consistent with the effects of low level windshear resulting from the shielding effect of the trees upwind of the strip. This accident was not the subject of a formal on scene investigation.

The pilot had been flight checked for solo flying in the morning prior to the accident. On the first solo circuit when on approach to land the pilot realised the glider was lined up too close to several gliders parked in line ahead on the airfield. The approach was made in a light cross wind from the left. The pilot corrected in the wrong direction for the misalignment, compounding the problem. As the airbrakes had not been deployed the glider was unable to be landed beyond the parked gliders. After touchdown, despite an attempt to avoid the raised right wing of the closest glider,the left wing of the landing glider struck the right wing tip of the parked glider, swinging the landing glider toward the next aircraft in line. The left wing of the landing glider struck the right wing of this second glider, resulting in substantial damage to both aircraft. This accident was not the subject of an on-site investigation.

The pilot was spraying a mature cotton crop adjacent to the company strip. After 20 minutes of flight, and shortly after commencing another spray run, the engine failed suddenly. The aircraft was manoeuvred towards an adjacent paddock with short soyabeans but it could not be aligned with the rows before landing. The wheels dug into the wet ground and the aircraft overturned. While skidding backwards the fibreglass back of the cockpit broke, allowing a large quantity of mud into the cockpit and making the pilot's exit difficult. He eventually used the fire extinguisher to smash a window to facilitate egress. Witnesses saw flame and black smoke emitting from the aircraft at the time of the engine failure. The aircraft operator found that the rear bearing of one magneto had become loose. This allowed the timing to advance and the engine backfired. An air inlet hose between the air filter and the carburettor was split and was sucked into the carburettor, thus stopping the engine. This occurrence was not the subject of an on-site investigation.

Circumstances:

The pilot carried out a daily and preflight inspection prior to boarding the aircraft for the first flight of the day in the self-launching glider. He started up, taxied to the end of the runway, and carried out a short run-up before taking off. At approximately 100 feet after take-off, the engine stopped and the aircraft was seen to enter a left hand spiral descent until it crashed on the edge of the sealed flight strip, approximately two thirds of the way along the strip.

The pilot was dead when the rescuers arrived at the aircraft. The fuel cock was found selected to the OFF position. With the fuel cock selected OFF fuel was still leaking through the lines. The effect of the fuel leaking past the fuel cock would have been to extend the period of time between start up and engine failure if the fuel cock was left in the OFF position. Previous experience with VH-GXM indicates that there is sufficient fuel in the system, when the fuel cock is selected OFF, to permit a start-up, DEPARTURE and climb out to approximately 500 feet.

On the accident flight the pilot taxied further than normal, and he carried out a short run-up. This could have accounted for the engine stoppage at a lower height than previous experience indicated. At the time of the engine stoppage there were two options open to the pilot. One was to land in the runway length remaining and the other was to turn left and land in the open paddock beside the strip. Either option would have been acceptable and the pilot, who was experienced, should have been able to glide to a safe landing.

The pilot's injuries were insufficient to cause death. The pilot did have extensive pre-existing cardiac damage. The factors which led to the loss of control could not be positively determined. It is possible that the pilot omitted to turn the fuel on prior to start up and the sudden loss of power at a critical point during the take-off caused a heart problem and subsequent loss of control.

No evidence was found which indicated that the pilot had suffered heart pain prior to the accident. The extended operation of the engine, with the unserviceable fuel cock selected OFF, could have lulled the pilot into a false belief that the aircraft was performing normally and that all checks had been completed correctly.

Significant Factors:

The following factors were considered relevant to the development of the accident:

1. Inadequate pre-flight preparation - the fuel selector was not placed in the ON position.
2. Defective fuel cock.
3. Loss of control in flight, possibly due to physical incapacitation.