Loss of control

Near the end of the landing roll the left wing rose and the aircraft lifted off the strip, then settled back onto the ground on the right mainwheel. The brakes were still applied and the aircraft turned sharply to the right and the right wing struck the ground. The aircraft rolled over and came to rest inverted. The pilot had assessed the crosswind component affecting the main property strip as being close to the maximum for the aircraft type. He had therefore decided to use an adjacent area, which was aligned into wind, but because of the position of buildings at the end of the area a go-around was not possible. It is possible that mechanical turbulence from the buildings effected the aircraft during the landing roll. The approach was conducted at a higher airspeed than that recommended in the P charts, and heavy braking was applied on touchdown before the tailwheel had contacted the ground.

The pilot reported that he was flying straight and level at 200 feet above ground level(AGL) and about 55 knots when the aircraft sideslipped to the left and nosed over. The nose continued to drop to the almost vertical position and the speed built up to 60 knots. At about 100 feet AGL, the pilot attempted to pull out of the dive but the aircraft did not respond and struck the ground in the almost vertical nose down attitude. Eyewitnesses reported that the aircraft was in the circuit area when they saw a wing drop and the nose of the aircraft fall sharply. The AUF Safety Officer reported that the flying surfaces of the aircraft were undamaged and he suspected that a stall/spin DEPARTURE was experienced by the pilot. In addition to cuts and bruises, the pilot suffered compound fractures to both legs and his right arm. This accident was not the subject of a formal on scene investigation.

When the pilot arrived at the destination, the wind was swinging from south to south-west and gusting from 15 to 35 knots. Runway 23 was unserviceable, and the pilot later advised that there were no suitable grass areas for an into-wind landing. An approach was made to runway 26, but during the landing roll the aircraft was affected by a strong wind gust. The pilot was unable to maintain directional control, and the aircraft groundlooped, collapsing the right maingear. The pilot was relatively inexperienced on tailwheel type aircraft. He had elected to make a landing approach after being informed that the present wind was from 190 to 230 degrees at 18 knots. This would have resulted in a crosswind component of between 9 and 15 knots, while the maximum allowable for the aircraft type was 12 knots. More favourable landing conditions existed at other aerodromes in the area. The pilot had apparently not considered the possibility of strong wind gusts as he made the approach.

After a dual check the pilot's instructor briefed the pilot to carry out two circuits, each with a full stop landing. Following the first circuit and landing, the pilot applied power to commence the take-off without bringing the aircraft to a stop. The aircraft veered sharply to the left, became airborne momentarily, before settling back onto the ground outside the flight strip. Flaps were selected fully down and the aircraft continued under full power across a storm water drain for another 38 metres before coming to rest. This was the pilot's second solo exercise. Following the loss of directional control it appears that the pilot became confused and did not apply the correct control inputs to bring the aircraft to a stop.

The pilot had been spreading in the general area of the strip for most of the afternoon. When he commenced operations to the south of the strip an area of sink was experienced on approach to the selected paddock. To allow for this, a reduced weight was uplifted on following flights, and a further six loads were spread successfully. However, as he commenced the turn to line up for the first spreading run with a new load, strong sink and turbulence were encountered. Realising that the aircraft would not clear a line of trees, the pilot continued the turn to the left but the angle of bank suddenly increased and the nose pitched down. The pilot dumped the load and applied right rudder but the aircraft struck the ground heavily. No defect with the aircraft was subsequently discovered which may have contributed to the development of the accident. It was likely that the aircraft was affected by a strong wind gust, which generated a substantial downdraft. The aircraft stalled during the pilot's efforts to avoid the trees, and there was insufficient height available in which a recovery could be effected. It was possible that had the pilot dumped the load before the aircraft stalled, the aircraft may have had sufficient performance to counteract the downdraft.

As the pilot was unfamiliar with operations at Bankstown, he had arranged to land at a strip near Hartley to pick up another pilot who would accompany him to Bankstown. The pilot inspected the strip from the air and was advised by the pilot on the ground to land uphill, into the north-east. A landing in this direction resulted in a quartering 10 knot tailwind. The aircraft bounced on touchdown and began to swing to the left. Being unable to regain directional control, the pilot applied full power to go-around as the aircraft went off the strip and over an embankment. During the go-around the tailplane struck a fence, and the aircraft came to rest against the fence, 38 metres to the left of the strip centreline and 250 metres from the initial point of touchdown. The pilot had not allowed for a crosswind component during the landing, and once the swing developed he was unable to correct it. The strip did not meet the width requirement for a private ALA.

The pilot was spraying a crop with liquid fungicide. As he pulled up to clear trees during the third swath run, the fungicide evidently surged in the hopper, and a quantity escaped past the hopper-lid seal. It then splashed over the windscreen, severely restricting the pilot's forward vision. He elected to return to the strip to clean the screen and check the hopper seal. The strip length was about 1000 metres and the pilot did not consider it necessary to dump the remainder of the load. During the landing, which was made in light downwind conditions, the pilot experienced difficulty in seeing the strip. During the latter stages of the ground roll the aircraft began to veer to the right. Corrective action failed to redress the situation and the right wing struck the fence bordering the strip. The aircraft came to rest after sliding sideways into a ditch alongside the fence, some 315 metres from the point of touchdown. Investigation confirmed that the hopper-lid seal was defective, and had apparently been so for some time. Directional control had been lost during the landing roll shortly after the free-castoring tailwheel had settled onto the ground. The combination of restricted forward visibility, a downwind/crosswind component and the relatively heavy all up weight, had prevented the pilot from making a safe landing.

The pilot held the aircraft on the brakes and did his run up checks then commenced take off to the west with a ten knot crosswind from the left. As the tail lifted the aircraft commenced a swing to the left which the pilot was unable to control with full right brake and rudder. He closed the throttle, the aircraft swung sharply left and the right main leg and tail wheel leg collapsed. Inspection of the aircraft showed that the right brake torque plate was attached by welds, one of which failed due to poor quality and low penetration of the weld. This allowed a degree a movement of the torque plate but did not appear to impair the brake operation. One of the three left main wheel through bolts had failed, following 90 per cent progressive fracture in a manner typical of low stress high cycle fatigue cracking. This allowed the wheel halves to be forced slightly apart at this section, causing distortion of the brake disc and drag contact with the brake pads at each wheel rotation. With operation on the ground the effect would have been increased due to the weight of the aircraft and rolling contact with minor strip surface undulations. It was also established that the left brake could be applied normally but that sometimes when the brake was released the brake remained partly applied. The circumstances of the investigation were such that the reason for this was unable to be determined. The uncontrolled swing on take off most likely resulted from the combined effects of the cross wind, the failed wheel through bolt and unidentified defect which caused the left brake not to release fully after it had been applied.

Some time prior to the attempted flight problems had developed with the right wheel assembly. Another pilot had carried out maintenance on the assembly and had subsequently test flown the aircraft. A short time later the pilot concerned boarded the aircraft and prepared for take-off. During the latter stages of the take-off roll, the right wheel slewed sideways, directional control was lost, and the aircraft collided with a fence. The reason why the right wheel slewed sideways was not determined. This accident was not the subject of an on scene investigation.

Upon arrival in the circuit, the pilot assessed the conditions and approached to land into wind on runway 04. When the nosewheel was lowered onto the runway, the aircraft veered to the right and did not respond to the application of left rudder. A go-around was initiated, but soon after becoming airborne, the aircraft rolled to the right until it reached a bank angle of about 60 degrees. The pilot attempted to counter the roll with the application of opposite aileron but the aircraft continued to roll right until the starboard wingtip touched the ground. The auxiliary wingtip tank ruptured and caught fire. The nose of the aircraft dropped and the aircraft struck the ground heavily in a wings level attitude. The aircraft ran along the ground for 18 metres before the nosegear collapsed. It then slid to a halt 250 metres beyond the runway markers with flames now emanating from the engine bay and right wing. The occupants evacuated the aircraft successfully. The pilot reported that after exiting the aircraft he sighted the windsock which indicated a wind direction of approximately 310 degrees and estimated the speed to have been 35 knots. During the early part of the landing roll the wind backed to a 35 knot crosswind from the left. This wind change was unforecast and unexpected by the pilot. It is probable that the wind change caused the left wind to lift and as a result the aircraft turned downwind. During the attempted go-around, in what was now a 35 knot tailwind, the aircraft stalled and the right wing struck the ground.