As the helicopter was brought to a 20 foot hover, it began to swing to the right. The pilot applied left pedal but the rate of turn continued to increase rapidly until the helicopter impacted the ground. The right skid broke off and the aircraft came to rest on its right hand side. Examination of the tail rotor pitch control system revealed that the bolt which connects the tail rotor pitch control arm to the control rod, below the tail rotor gearbox, was missing. The bolt was never found and the reason for its absence could not be determined. It was evident that the loss of the bolt resulted in the loss of tail rotor control.

The pilot had built the single seat aircraft himself and had previously only flown it on one occasion. After completing the first circuit, the aircraft was taxied back to the threshold and the second take-off commenced. Just after lift-off the aircraft was observed to pitch nose up. The right wing dropped and the aircraft turned to the right before impacting the ground. When the aircraft tail came up during the take-off roll, the pilot became concerned that it was too high and that the propeller might strike the ground. In attempting to avoid this, excessive back pressure was applied to the control column. The aircraft became airborne prematurely and then stalled.

After crossing the threshold at 75 knots power was reduced to idle and a landing flare commenced at about 25 feet agl. The aircraft floated for some distance before the nosewheel contacted the ground heavily 400 metres from the threshold. A bounce ensued followed by a further heavy touchdown on the nosewheel which then collapsed and was torn off as the aircraft slid on its nose for 98 metres.

Circumstances:

The aircraft was conducting cattle spotting operations from an estimated height of between 90 and 150 metres above ground level. The pilot was relatively new to the task and was being guided by the passenger, who was in radio contact with the ground mustering party. The procedure was for the aircraft to spot and then fly directly over cattle as a guide to the ground party. Following the first flight of the day, the aircraft was refuelled from a newly opened 200 litre drum of aviation gasoline. The aircraft then took off normally and flew over one group of cattle before heading north-east towards another area. A short time later, a high revving engine noise was heard followed immediately by the sound of impact. The aircraft had impacted the ground 48 degrees nose down and slightly right wing low on a heading of 158 degrees Magnetic. The fuel tanks ruptured on impact, and the wreckage caught fire. The extent of the fire damage was such that a thorough examination of the wreckage was not possible. However, of the components that were able to be checked, no fault was found which might have prevented normal operation of the aircraft. The engine was operating at impact, and the flaps were at 15 degrees. The steep nose down attitude of the aircraft at impact is typical of what might be expected as a result of the aircraft stalling at low level and the pilot having insufficient height to effect recovery. While there is no proof of this occurring, there were circumstances existing which could have contributed to its development. These included the sun being on a Magnetic bearing of 40 degrees and an elevation of 25 degrees above the horizon at the time of the accident, indicating that the pilot could have been affected by sun glare as the aircraft headed north-east. During the refuelling stop, the passenger remarked on the turbulent conditions at the operating height of the aircraft. If the aircraft was operating at comparatively low speed (and the flap setting probably indicates this), then the turbulent conditions could have upset the aircraft to the extent that it stalled, with the sun glare preventing the pilot detecting the upset.

Factor

The following factor was considered relevant to the development of the accident:

For reason(s) which could not be positively established, the pilot lost control of the aircraft at a height from which recovery to normal flight could not be effected.

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.