During the take-off roll the aircraft had reached a speed of about 85 knots when the left engine suddenly lost power. The pilot immediately closed both throttles and applied braking, but was unable to prevent the aircraft over-running the 900 metre strip. The landing gear was torn out before the aircraft came to rest. Initial investigation revealed that the take-off attempt had been made with the fuel tanks selected to the auxiliary positions, and these tanks were about one quarter full. It is probable that the fuel ports became uncovered as a result of the take-off acceleration, allowing the ingestion of air to the fuel system. The pilot normally followed a written checklist, but had omitted to use it on this occasion. After checking the fuel system during the before take-off vital actions, he had inadvertently left the fuel selectors on the auxiliary positions.

About 30 minutes after takeoff the aircraft was observed by witnesses to be heading in an easterly direction at about 500 feet above ground level. It was then seen to turn left, head north and commence a gradual descent. The witnesses then reported that another left turn was commenced and both wings folded back. The aircraft entered a steep descent before impacting with the ground. An inspection of the aircraft revealed that the left wing front drag cable had failed, due to fatigue and overload, at the forward end near to the attachment point. The failure of this cable resulted in the wings folding. The manufacturer of the aircraft had published a technical bulletin some seven months prior to the accident recommending that owners replace all the wires on their aircraft and fit a double drag brace system. The owner pilot of this aircraft was aware of the recommendation but had not made the nesessary modifications.

The aircraft was one of a number conducting a "fly-in" to the property. On arrival overhead the farm, the aircraft was observed to make a low pass over the homestead, during which the pilot attempted to drop flour bombs on the building. While the pilot was attempting to drop the bombs, the right wing of the aircraft stuck a tree about five metres above the ground. The aircraft rolled to the right and collided with the ground beyond the tree. An inspection of the wreckage did not reveal any defects that could have contributed to the accident. The pilot had recently been counselled by members of his Association regarding previous instances of low flying.

The aircraft departed from runway 16 at Melbourne and after becoming airborne the gear was retracted normally. A left turn was commenced at 500 feet which placed the aircraft on right base for runway 17 at nearby Essendon Airport. The gear selector was placed in the DOWN position as part of the pre-landing procedures but the aircraft subsequently landed with the gear retracted. Minor damage was sustained to the under-fuselage skin, gear doors and various aerials. Inspection revealed that the shear pin located in the forward door actuating linkage had failed. This pin is designed to shear if the doors attempt to operate out of sequence. The pre-impact rigging position of the doors could not be confirmed due to damage caused by the landing. The pilot reported that on short final he checked the gear lights, which were selected to dim. Because he failed to see the gear door warning light, which was the last and most conspicuous in the sequence, he assumed that he had a gear down indication.

The pilot had been carrying out a solo cross-country training flight, when deteriorating lift forced him to make an outlanding. The approach to the paddock selected involved passing over a line of high trees. Severe sink was encountered and the pilot realised he would not clear the trees. He therefore applied full spoilers and attempted a landing short of the planned area. During the landing roll the glider collided with a flock of sheep, killing five of the animals on impact. The pilot was a Japanese national who was visiting the area. Before DEPARTURE he had advised the soaring club that he wished to undertake a local flight. As a result, he was not briefed on cross-country procedures and outlandings. When thermals were encountered after take-off, he had elected to conduct a longer flight. When the outlanding became necessary, the pilot had misjudged the strength of the wind and had continued downwind beyond the point where a successful approach to the selected paddock could be made.

Circumstances:

The aircraft was engaged in superphosphate spreading operations. An aerial survey of the property had been conducted by the pilot in company with the property owner. Power poles in the valley ahead and to the left of the airstrip were marked. When operations started the wind was a light north-easterly and ambient temperature was 16 degrees Celsius. By the time the aircraft had refuelled and was ready for the thirty-sixth flight of the day, the ambient temperature had increased to 28 degrees Celsius, and the wind direction had changed to a south-westerly. Shortly after take-off, the aircraft was observed to sink after overflying the high-voltage powerlines between the marked poles. On the next flight the aircraft was observed to make a tight left turn and fly down the valley adjacent to the left marked power pole. On the next and final flight, the aircraft was apparently attempting to follow the track of the previous flight. While crossing the powerlines south-west of the marked power pole, the aircraft's landing gear and left wing tip struck the powerlines. With the broken powerline jammed behind the left aileron washout plate, the aircraft impacted the ground 100 metres beyond the power pole. Ground impact forces destroyed the aircraft and reduced the cockpit area to non-survivable dimensions. On-site examination of the aircraft and subsequent laboratory examination and testing of components did not reveal any pre-existing mechanical defects or abnormalities which could be considered as factors in, or contributory to, this accident. Powerline impact marks on the aircraft were consistent with the aircraft being in a left banked attitude when it struck the wire. The investigation revealed that the loader driver's truck bucket load gauge had no conversion/calibration chart, and that the aircraft was being operated in excess of the maximum allowable weight for take-off. It is considered probable that the pilot had elected to fly down the valley, (thus taking advantage of the downslope), to compensate for a degradation of aircraft performance whilst operating overweight in the changed ambient conditions. The absence of a superphosphate trail before wire impact indicates that the pilot did not dump any of the load and was either unaware of, or had forgotten about, the existence of powerlines to the south-west of the marked power pole.

Significant Factors:

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

1. The aircraft was being operated in an overweight configuration for take-off.

2. The pilot did not adjust the take-off weight of the aircraft to give an acceptable climb performance.

3. The pilot was unaware of, or had forgotten about, the powerlines to the south-west of the marked pole; or,

4. the pilot misjudged the clearance between the powerlines and the aircraft whilst trying to overfly them.

The pilot reported that he encountered severe turbulence at 1500' and that he reduced power to slow to the turbulence penetration speed. When the aircraft cleared the rough air the throttle was advanced, however, the engine stalled. The aircraft was established in a glide configuration and a paddock was chosen in which to land. The approach was flown at a speed in excess of that normally used for a powered approach resulting in the tailwheel contacting the surface prior to the mains. When the mainwheels contacted the paddock the struts bent and allowed the propeller to strike the ground. The aircraft could not be controlled during the ground roll and it skidded through a fence and onto a roadway. This accident was not the subject of an on scene investigation.

Circumstances:

The aircraft was engaged in a medical evacuation flight carrying an injured crewman from a ship located west of Augusta. During the turnaround at Augusta the pilot noticed that one corner of the polyurethane covering on one tail rotor blade was lifting. After consulting the company engineer in Perth the pilot cut the loose material from the blade and continued with the flight to Perth. Slight vibration was felt after approximately 30 minutes and 15 seconds later the vibration became severe. The pilot carried out a precautionary landing. An inspection of the tail rotor blades indicated that a significant amount of the polyurethane covering on the blade not modified by the pilot had been lost. The blade's polyurethane covering had been replaced approximately 4 hours before the occurrence. The bonding process used, although in accordance with the manufacturer's recommendations, was defective. The manufacturer had developed a new process prior to the occurrence, however, details of this had not reached the Sydney based overhaul facility at the time the cover was replaced.

Significant Factors:

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

1. The design of the polyurethane replacement process used on the failed blade was defective.

The pilot reported that he made a short field approach to the 080 degree strip in a 10 knot easterly wind. He said that on short final approach some sink was encountered which resulted in the aircraft touching down short of the threshold. The pilot believed that touchdown was normal for a short field approach but the wheel marks on the strip suggested that it may have been heavy. When the aircraft touched down, the right main gear tracking arm (P/N 105-810021-4) broke. This resulted in the wheel assembly detaching. The aircraft skidded to a stop after rotating to the right through about 170 degrees. The broken tracking arm was subjected to microscopic examination which determined that it had failed due to overload. There was no evidence of any fatigue or pre-existing damage. In addition, the damage to the wings was also consistent with a heavy landing.

The pilot was landing the aircraft in gusty wind conditions. As the aircraft was flared for landing, it touched down heavily nosewheel first, and bounced. Power was applied to assist in regaining control. During the second touchdown the nose dropped, the nosegear collapsed and the aircraft overturned. After the accident the pitch trim devise was found to be in a nose-down position. The pilot advised that he usually selects a nose-up position for landing. This accident was not the subject of an on-site investigation.