Loss of control

Towards the end of the landing roll the aircraft began to diverge to the right. The pilot unsuccessfully attempted to correct the situation and the aircraft ground looped. The left main gear leg was broken off and the left wing, tailplane and the propeller struck the ground. The pilot was inexperienced on tailwheel aircraft and the landing was conducted in light quartering tailwind conditions.

When the gear was selected down it did not fully extend and the gear circuit breaker tripped. Initially the circuit breaker could not be reset nor could the gear be lowered using the emergency system. The circuit breaker was subsequently reset and a gear down indication obtained. Shortly after touchdown the aircraft yawed until it was travelling backwards. The tailskid struck the runway and the aircraft came to rest after turning through a further 90 degrees. The right main wheel was found to have turned through 90 degrees because the scissor linkage arms had become disconnected. A castellated nut and its retaining split pin was found to be missing from the bolt which joins the scissor linkage arms. The reason for the loss of these items could not be positively established.

The pilot reported that, after commencing the take-off with flaps up, he selected 10 degrees of flap and rotated at 60 knots. Although the aircraft became airborne it did not climb normally. The aircraft struck a telephone line near the end of the strip and then landed in a paddock before passing under a power line. With full power still applied, the pilot attempted to clear a fence but the wing leading edges struck fenceposts. The aircraft landed heavily and came to rest 478 metres from the strip end. The take-off performance had been degraded by a loss of engine power resulting from unserviceable piston rings in two cylinders. The aircraft was being operated at some 120 Kilograms in excess of the weight extracted from the performance charts as being the maximum allowable for the strip length.

Circumstances:

There was a thunderstorm in the vicinity of Koolan Island when the aircraft arrived, and the pilot held until the storm had cleared the area. The pilot made a normal full flap approach touching down approximately 300 metres into the 661 metre strip. After approximately 100 metres of ground roll on the wet gravel/coral strip, all braking effectiveness ceased. The pilot attempted to steer the aircraft to the left to avoid overrunning the end of the strip, however, the aircraft skidded, turned through 180 degrees, and came to a stop partially off the strip, resting on the cargo pod and the right wing tip. After the aircraft stopped the pilot observed the surface was hard, there were oil-soaked areas on the surface and water was still running off the strip.

On the morning of the accident a periodic inspection had been completed on the aircraft. Following this inspection, the pilot, accompanied by an engineer, carried out a satisfactory test flight in the helicopter. The pilot then lunched with the engineers and after farewelling them at the airport was driven to the helicopter to prepare for the flight back to the mustering camp. The helicopter was later observed by a stockman who was travelling in a vehicle towards the mustering camp. When the helicopter was first seen it was flying at a height of about 200 feet above the tops of the trees in the direction of the camp. It then appeared to stop, turn abruptly through 90 degrees to the left, roll to the left and spin through 360 degrees before impacting the ground inverted. At about the same time as the helicopter turned to the left an object was seen to fly horizontally away from the aircraft to the right. After ground impact a fire broke out and engulfed the wreckage. An extensive search of the area failed to locate the object that had fallen from the helicopter. However it is believed that the object may have been one of several cans of oil or grease the pilot was known to have carried in the aircraft. The examination of wreckage did not reveal any defect in the helicopter which was likely to have contributed to the occurrence. The reason for the loss of control by the pilot could not be determined.

The aircraft had been parked in the open overnight. When the pilot arrived at the strip he noted that shallow fog had settled over the area. The temperature was below freezing point and frost covered the aircraft, except for the windscreen which had been protected by a cloth sheet. A pre-flight inspection was carried out, but did not include the removal of the frost from the aircraft. Because the fog had reduced visibility to about 50 metres, the pilot taxied the aircraft along the strip to check for obstructions. During this time the moisture froze on the windscreen, however by reaching from the cockpit the pilot was able to clear the left side of the screen. Shortly afterwards the take-off was commenced and the lightly loaded aircraft became airborne after a ground run of about 250 metres. At this point all forward visibility was lost because of frost re-forming on the windscreen. The pilot noticed that the aircraft appeared to be banking to the left and he elected to land immediately. The left wingtip contacted the ground, followed by the main wheels. The aircraft ran off the side of the strip and collided with a fence, before coming to rest about 100 metres from the strip. The pilot had had no disciplined instrument flying experience and had been unable to maintain effective control of the aircraft during the take-off with severely restricted visibility. The degradation in aircraft performance as a result of the frost covering the wings and tail surfaces could not be established.

Circumstances:

The student pilot had completed a period of instruction and a follow-up solo sortie on the morning of the accident. He was landing following a further period of solo circuits when the accident occurred. The aircraft appeared to touch down normally but then veered to the right without any apparent attempts at correction. The aircraft left the runway and crossed a small embankment before going through a fence into the adjoining paddock. It is possible that the pilot had reached task saturation after the third hour of flying involving stalling, incipient spins, and circuit work. The pilot was also tending to land flat and fast. It is probable that the aircraft started to "wheelbarrow" as a result of the approach technique used and the pilot did not react in time to avoid the DEPARTURE from the runway.

The pilot had completed one circuit involving a touch and go landing. As power was applied for the take off phase of the second touch and go, the aircraft swerved to the left with the left main landing gear clear of the ground. The pilot was able to arrest the left swing but the aircraft continued to track beyond the confines of the flight strip. After impacting a fence post and two drains, the nose and left main gears were dislodged and the left wing impacted the ground. The investigation revealed that the pilot had used an incorrect crosswind control technique and failed to maintain directional control of the aircraft during the ground roll. The pilot delayed abandoning the take off phase of the touch and go sequence. The position at which the power was reduced and the take off abandoned could not be determined. There were no pre-existing defects with the aircraft which could have contributed to the accident. This accident was not the subject of an on-site investigation.

At the conclusion of a parachute dropping sortie, the pilot landed the aircraft at the strip in a strong crosswind. During the landing roll the aircraft began to swing to the left and the right gear leg collapsed. The right wing, tailplane and elevator were bent after contacting the ground. The aircraft was one of four operating from the strip, when the wind backed and increased in strength, during the passage of a weak front. The pilot had been aware of the change in wind velocity before attempting the landing.

The pilot stated that just after the aircraft became airborne it encountered a strong gust of wind. The left wing tip and nosewheel struck the ground and the aircraft overturned. During the take-off run the pilot held back pressure on the control column and at 50 knots selected 10 degrees of flap, the aircraft becoming airborne after a ground roll of only 170 metres. The take-off distance required was 650 metres, however, the take-off was attempted on an unprepared salt pan with an available take-off distance of 300 metres. The pilot had operated from this area previously but on this occasion the aircraft was at a higher all up weight. The wind gust reported by the pilot was probably associated with a willy willy, encountered when the aircraft was at a low airspeed.