Circumstances:

The pilot was landing after his first flight on type. The aircraft bounced on touchdown, resulting in a heavy landing and consequent cracking of the fuselage near the main wheel mounting.

Circumstances:

The aircraft was being ferried to a strip in the Hunter Valley to carry out parachute dropping. En-route, although performance appeared normal, the pilot sensed a possible problem with the turbine engine and landed at Somersby NSW. After landing, a visual inspection of the engine was undertaken and several ground runs carried out, without any defect being found. The pilot elected to return to Camden where further checks could be made. The aircraft took off towards the south and climbed to a height of about 1000 feet, at which point the pilot heard a bang from the engine compartment which was followed soon after by a very loud bang associated with noises described by the pilot as like "forcing a crowbar into the engine".

During the ensuing forced landing in fine, calm conditions, the pilot misjudged the final stage of the landing approach, resulting in the aircraft landing very heavily and sustaining considerable damage. A subsequent engineering investigation found the engine had suffered a catastrophic malfunction resulting from fatigue failure of a helical thrust washer from the high-speed pinion assembly. The fatigue crack growth resulted from applied alternating loads, probably due to excessive wear of the helical gear shaft bearing. About one week prior to the flight, engine oil sample and filter element had been removed in accordance with Airworthiness Directive AD/TPE 331/9.

Although the samples had not been immediately sent for laboratory analysis, the owner was allowed to operate the engine for a further 50 hrs before satisfactory test results were received. When the samples were examined during the investigation, articles were found which indicated bearing deterioration prior to the engine failure. Earlier in the year, the aircraft had sustained a propeller ground strike, resulting in the engine being removed and returned to an overhaul facility for inspection. It has been reported that when the engine was re-installed in the aircraft, a torque meter calibration check was not carried out in accordance with the procedures published in the manufacturer's maintenance manual. Although not positively established, the mode of engine failure was consistent with an excessive torque setting.

Significant Factors:

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

1. Probable excessive wear of the helical gear shaft bearing.

2. Torsional loading of the helical thrust washer from the high-speed pinion gear assembly.

3. Fatigue failure of the helical thrust washer.

4. Pilot-in-command misjudged distance, speed and altitude during forced landing approach.

Circumstances:

Some months prior to the accident the pilot had begun learning to fly ultralight aircraft. Around this time, he also began to have spells where he was able to see and hear people but could not move or talk to them. His instructor recommended that he stop flying and complete medical tests. The pilot later purchased and assembled a gyrocopter. Over a two-month period he learned to fly the craft. On the morning of the accident, he asked a more experienced gyrocopter pilot to fly his machine and check its characteristics. The other pilot found that it was quite satisfactory. Those who had observed the pilot flying previously considered that he had no problems in controlling the aircraft. The gyrocopter was observed on final approach, but it then disappeared for a short time, having flown an orbit to the left. After adopting a final approach for the second time the gyro flew towards the strip at about 50 knots. A witness observed the craft roll to the left from a height of about 30 feet. The gyrocopter impacted the ground in a left bank of about 130 degrees. No evidence of pre-impact failure of the aircraft was found.

Significant Factors:

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

1. The cause of the accident was not positively determined. It is possible that the pilot suffered a temporary incapacitation during the approach.

Recommendations:

1. That the Civil Aviation Authority undertake, or oversee, an education campaign intended to remind sport aviation pilots of the need to consider their standard of health before undertaking flying activities.

While flying at about 500 feet above ground level the aircraft evidently experienced severe vibration, and the inboard half of the right aileron was torn from the wing. The pilot attempted to deploy the parachute system, but the rigging lines wrapped around the propeller shaft. As a result, the parachute canopy did not open, but trailed between the propeller and the tail plane. The aircraft subsequently stalled and spiralled to the ground. When impact occurred, the complete left aileron was seen still falling. It was found 60 metres short of the aircraft impact site and the right aileron was found 148 metres short of the impact site. There is no known technical data available for this prototype aircraft, on which the control surfaces were not mass balanced. The pilot had experienced probable in-flight flutter on an earlier, different ultralight which he had designed and built. He had eliminated the problem by mass balancing the ailerons. An airspeed of about 80 knots could be considered critical for the initiation of flutter of unbalanced control surfaces on ultralight aircraft. From measurements and numbers recorded by the pilot on his map, it was concluded that the aircraft had probably been travelling in excess of this speed. Control surface flutter may have also been induced if some element of the control system had failed or had not been assembled or maintained to minimize flexibility and mechanical tolerances. A detailed inspection of the wreckage has determined that the control rod support lugs on the right aileron control horn may have failed along the weld line. There may also have been torsional flexibility of the aileron and the wing, which could have led to flutter at high speed.

The pilot was a member of the French team competing in the "Austraglide `86" gliding championships. At the end of a cross-country exercise the pilot reported that he was 5 kilometres from the finish line. The pilot of another glider observed that when the subject aircraft was one kilometre from the line it was apparently low. Shortly afterwards the glider collided with power lines. The tailplane was cut off by this impact and the glider then struck the ground in a steep nose down attitude. The glider was seen leaving an area of thermal activity with apparently sufficient altitude to complete the flight to Benalla. The reason why the glider subsquently descended to the low altitude which resulted in the collision with the power lines could not be determined.

The pilot was making a take-off in 15 knot crosswind conditions. Initial acceleration appeared to be normal, and the aircraft lifted off at 60 knots. However, about 30 metres further on the aircraft settled back onto the ground, became airborne again but then failed to perform as expected. It cleared a fence at the end of the strip, before touching down again in the adjacent paddock and subsequently striking an electrified fence. The wooden propeller shattered and the right landing gear was torn off before the aircraft came to rest some 880 metres from the start of the take-off run. Although the pilot observed no engine abnormality during the takeoff, subsequent tests found that both magnetoes were not operating normally. It is possible, therefore, that the engine suffered a partial loss of power during the takeoff run. It is also possible that the prevailing wind conditions caused a loss of performance shortly after liftoff, and that the high nose attitude adopted by the pilot further added to this performance loss.

The pilot was engaged in the spraying of sugar cane. During one of the swath runs as he turned the aircraft to follow the line of the cane the right wing struck the cane. The aircraft impacted the ground and bounced several times before coming to rest. The configuration of the spray run chosen, by the pilot, involved a turn through 33 degrees during the run. The aircraft was being operated at a lower altitude than was necessary under the prevailing conditions to complete the task. The combination of both these facts made the judgement of wingtip clearance during the run extremely difficult.

The aircraft had been out of service for several months, undergoing engine maintenance. This was the first flight following the completion of that maintenance. After takeoff the aircraft was observed to climb normally to about 1500 feet. It was then observed to begin trailing black smoke and shortly afterwards turned towards the airfield and began to lose height rapidly, until descending out of view behind trees. The aircraft touched down heavily, tail first, in a paddock, bounced and following the second touch down slewed sideways through a fence and down an embankment. An inspection of the engine revealed that both the right and left camshaft inclined drive upper bevel shaft gears had been overheated as a result of a lack of lubrication. The distortion of the left drive was sufficient to disconnect it from its camshaft drive bevel gear resulting in the subsequent loss of power. The engine was fitted with an external oil priming system to lubricate the camshaft drives during and immediately after starting. This system was connected on each side into the appropriate valve train oil supply by "T" fittings and flexible hose assemblies. During reassembly, associated with the latest engine maintenance, the "T" fittings were omitted and the fittings in the front case drillways were blanked with plugs, effectively cutting off the engine oil supply to the camshaft drives. It was evident that the maintenance personnel involved were unaware of the camshaft lubrication system.

The helicopter pilot was being examined by a Civil Aviation Authority Examiner of Airmen for a rappelling endorsement. The helicopter and crew were also involved in rappelling refresher training for police crewmen. While the helicopter was in a stable hover at 80 feet AGL over an obstacle free area and in ideal weather conditions, two trained crewmen rappelled from the helicopter. Both crewmen departed the helicopter simultaneously but the crewman on the right side misjudged the time for braking before ground contact and struck the ground heavily.

When the aircraft arrived in the destination area, another aircraft was also in the circuit. The pilots were in communication with each other, and arranged that VH-CUO would land after the other aircraft. However, the pilot of VH-CUO apparently misjudged the relative speeds of the two aircraft. He initiated a go-around from a position on final approach to runway 15, when there was evidently insufficient separation with the preceding aircraft to allow a normal landing. The aircraft remained at a low height above the ground, and the pilot broadcast a message that he intended to land in the opposite direction, on runway 33. The wind at the time was from the south-east at about 10 knots. Witnesses observed the aircraft as it tracked along the western side of the runway. The turn onto base leg was made at an angle of bank of about 60 degrees, and about three-quarters of the way around the turn, the nose of the aircraft dropped rapidly. The aircraft then dived steeply to the ground, and was destroyed by the impact and subsequent fire. The subsequent investigation did not reveal any defect or malfunction which might have affected the operation of the aircraft. The pilot was conducting an operation known as a "bank run", and there is pressure on pilots performing such runs to adhere to the prescribed schedules. The pilot's decision to perform a low level circuit and land downwind was considered to be related to his desire to arrive at the terminal as close as possible to the scheduled time. While conducting the circuit, the aircraft stalled during a turn at a height which was too low to allow the pilot to recover control before impact with the ground.