Circumstances:

After a smooth touchdown and a landing roll of about 150 metres, the right undercarriage leg collapsed. The aircraft veered right about 25 metres off the runway and came to rest in soggy ground. Prior to touchdown the landing gear had been confirmed down by the pilot and had been seen down by ground witnesses. An engineering inspection discovered that an end fitting on the link assembly side bracing lock had partially seized. This had prevented the right undercarriage leg from locking down. The last 100 hourly periodic inspection had been carried out eleven months prior to the accident. Since then, the aircraft had flown only 60 hours. The end fitting lacked lubrication and is not equipped with a grease nipple. This accident was not the subject of an on-scene investigation.

The pilot reported that his approach to land towards the north-west was good, however the aircraft floated for some distance before touching down. As the aircraft landed the sun appeared from behind a cloud and the pilot lost all forward vision. Braking was applied but, as the pilot considered that the aircraft was not slowing down and he was aware that the strip end was near, he applied power to go around. The aircraft failed to become airborne and collided with a bush and a fence beyond the end of the strip. The investigation did not reveal any fault with the aircraft that could have contributed to the accident.

The aircraft was being flown between 500 and 1000 feet agl at 60 knots with 20 degree of flap. A mob of sheep was spotted and the pilot turned right to keep them in sight. The stall warning sounded and the pilot noticed a lack of elevator control but did not associate this with a stall. Descent continued while the pilot was engrossed in the elevator problem until the aircraft struck trees in its path. A major portion of the right wing was severed and the aircraft came to rest on its side.

The aircraft was being operated on a VFR flight and was cruising at 1500 feet above ground level. The engine suddenly began to run roughly and the rpm dropped to about half the normal setting. Emergency trouble checks failed to alleviate the problem and the pilot transmitted a Mayday call as he tracked towards a nearby strip for a precautionary landing. The approach to this strip was too high and power was applied in an attempt to go around. However, severe engine vibration occurred and the pilot was committed to a forced landing in densely forested, hilly terrain. The power loss and vibration was caused by partial separation of the exhaust valve head on one of the cylinders.

The pilot noticed a low oil pressure reading and decided to land at a strip he had just overflown. As he turned the aircraft toward the strip the engine began to vibrate and backfire and it was shut down. The aircraft touched down 150 metres short of the strip boundary fence. After running through this fence the aircraft continued for a further 280 metres before coming to rest on the strip. Inspection of the engine revealed that the crankcase had been punctured by the connecting rod of the number 4 piston. The connecting rod assembly had been subjected to excessively high temperatures due to a lack of lubrication. The cause of the lack of lubrication to the assembly could not be determined. After the engine had failed, the pilot continued with his attempt to land at the nearby station strip although a closer, suitable area was available.

The pilot was approaching to land at the conclusion of his second flight on the type. The approach was normal, however the glider floated the length of the strip at a height of about 25 feet. At the end of the strip a turn was commenced but after completing about 90 degrees an incipient spin developed and the glider struck the ground. The pilot subsequently advised that he had activated the cruise flap lever instead of the air brake. The two levers are located side by side in the cockpit. It is likely that the pilot was suffering a degree of heat stress. He had been in the cockpit, exposed to the sun for two and a half hours and he had not eaten since breakfast. He reported that during the final stages of flight his reactions were affected by fatigue and the heat.

Prior to the flight the pilot checked the strip details with the owner. These included advice that there was a powerline on the approach. On arrival the pilot located a powerline near the north-east end of the strip. He assumed that this was the one to which the owner had referred, and decided to land from the opposite direction. On final approach, he saw a single wire powerline ahead and attempted, unsuccessfully, to fly beneath it. The aircraft yawed violently to the left as it struck the wire, but the pilot was able to regain control and safely land the aircraft. Post-flight inspection revealed that a section of the fin and the complete rudder assembly had been torn from the aircraft. The point of impact with the wire was 262 metres short of the strip threshold and occurred when the aircraft was at a height of about 30 feet above the ground. The span between the poles supporting the wire was 333 metres, and the poles were difficult to see against the background.

The student had completed five dual circuits and was then authorised to carry out two solo circuits and landings. During the second approach some turbulence was encountered and a hard landing was made. The aircraft ballooned to 5 metres and ground looped on the subsequent touchdown. After the aircraft had turned through 180 degrees its left wing tip scraped the ground and it nosed over. After the heavy touchdown the student had held excessive back pressure to keep the nosewheel off the ground. A wind gust caused the aircraft to become airborne and the pilot was unable to effect timely recovery action.

After landing on a claypan, the pilot taxied the aircraft along a track to pick up a passenger. The right mainwheel entered an area of bulldust and the aircraft swung to the right off the track. As the pilot was manoeuvring the aircraft back onto the track the right wing struck a tree. The pilot was attempting to save time by taxying towards the passenger. Forward visibility was impaired as the pilot was looking into the sun and there was glare on the windscreen. The tree struck was the only obstruction in the area.

The helicopter was being operated in clear conditions, with a five knot South - Westerly breeze, and an outside air temperature of minus six degrees Celsius. After landing on a snow covered ridge, the passengers advised that they would require only a short period of time to complete their work. While waiting, the pilot maintained sufficient power to prevent the helicopter sinking deeper into the snow than approximately 45 centimetres. On DEPARTURE, the helicopter lifted normally clear of the snow into the hover, then turned approximately 45 degrees to the left, to follow the ridge line instead of flying direct across the valley to the next destination. During take-off, slight sink was encountered. This was controlled by an increase in collective pitch, but almost immediately further sink occurred. The pilot again increased collective pitch and forward cyclic control expecting to accelerate through the sink. The skids contacted the snow surface, with the right hand skid digging in deeper, causing the helicopter to roll to the right. In response, left cyclic control and full collective were applied , but the helicopter continued rolling to the right, allowing the main rotor blades to contact the snow, which caused the helicopter to overturn. The prevailing conditions would appear to preclude the possibility of power failure caused by snow ingested through the engine air intake. A full mechanical inspection was made of the helicopter and its engine, but no fault was detected. It is possible the aircraft was over-rotated, allowing the skid toes to contact the snow. The cause of this accident was not determined.