Loss of control

The pilot landed the helicopter to allow his passenger to alight. The engine was left running, the cyclic frictioned and collective held fully down. The pilot then felt a low frequency vibration begin and almost immediately the left side of the helicopter lifted and the tail swung to the right. Control imputs by the pilot had no effect and the helicopter rolled onto its side. One of the four belts providing drive to the transmission had jumped off the sheave, for reasons which could not be established. The belt had become wrapped around the clutch shaft and had caused a sudden braking action to the main rotor blades. This braking force was of such a magnitude that the fuselage yawed in an inertia reaction. The right skid dug into the soft ground and a dynamic roll-over resulted.

The pilot was carrying out a cattle-spotting operation prior to the commencement of the muster. He descended the aircraft to 500 feet above the ground to get a better view of some animals amongst the trees. The pilot reported that as the aircraft was being returned to level flight it was affected by severe turbulence and the pilot's door became unlatched. While attempting to close the door he noticed that the indicated airspeed had reduced and that the aircraft was continuing to sink. A turn to the right, to clear the area of turbulence, was commenced but during the turn the aircraft stalled and entered a spin. Attempts to recover from the spin were unsuccessful and the aircraft struck the ground in a nose down attitude while turning to the right.

The pilot had intended carrying out a flight around the property. When he had not returned by nightfall his parents rang neighbours before commencing a search. The wreckage of the aircraft was found two kilometres north-east of the homestead. It had struck the ground while in a steep nose-down attitude, in a paddock with no obstructions in the immediate vicinity. Investigation revealed that the engine throttle cable was broken, however it was not established whether this had occurred before or after the impact. The wreckage distribution was typical of that which follows a stall with insufficient height remaining in which to effect recovery. However, the reason the aircraft apparently stalled could not be determined.

The pilot was conducting a series of circuits and touch-and-go landings. Both three-point and wheel landings were carried out without problem. On the final landing, touchdown was made in a three-point attitude at a speed of about 45 knots. After the aircraft had rolled for about 100 metres, the pilot applied even braking to both mainwheels. The aircraft immediately veered to the left, and the pilot was unable to stop the swing before the right maingear collapsed. No fault was subsequently found with the braking system of the aircraft, and there was no sudden wind gust or other meteorological condition which might have contributed to the accident. Although the pilot had a reasonable amount of tailwheel aircraft experience, he lacked currency in the Cessna 180. It was likely that on the final landing of the exercise he had unconsciously relaxed his level of concentration.

On arrival at his destination, the aircraft overflew the homestead. This was the pilot's normal practice, to indicate to persons on the ground that transport from the nearby strip was required. The aircraft was then seen apparently following a gully containing a sunflower crop in which the pilot and passenger were partners. Shortly afterwards the sounds of an impact were heard. The aircraft was found to have struck the side of the gully while in a steep nosedown attitude and probably rotating to the right. No pre-impact defect or malfunction of the aircraft was found which might have contributed to the development of the accident. However, about 12 months previously, the pilot had applied tape over the stall warning vane, thus depriving him of aural warning of an impending stall. The wreckage distribution was consistent with that which follows a stall at low level where control of the aircraft is not regained before impact. It was likely that the aircraft stalled while the pilot was manoeuvring above the crop, but the precise reason for the stall and subsequent loss of control was not established.

After arriving at the property that morning, the pilot commenced mustering operations. The operations were conducted between 50 feet and 300 feet above ground level throughout the day and all manoeuvres performed appeared normal to ground observers. Later in the afternoon a witness reported that he observed the aircraft perform a steeper than normal climb before diving towards the ground. The aircraft subsequently impacted the ground in a steep nose down, wings level attitude, bounced, then slid forward for 13 metres before the left wing struck a tree. Examination of the wreckage did not reveal any defect with the aircraft that could have contributed to the accident. It is probable that the pilot was fatigued after a long day and that he inadvertently allowed the aircraft to stall at the top of the climb. Insufficient height was then available to allow a recovery to be effected.

During the pre-landing checks, the pilot noted that no pressure was available from the left brake pedal. The strip has a slight slope, and the pilot elected to land up the slope in light quartering tailwind conditions. The aircraft bounced twice after touchdown and the pilot commenced a go around. The aircraft veered off the strip and collided with several trees before coming to rest 50 metres from the centre of the strip. The left brake had lost pressure because a worn seal had allowed air into the brake line. The pilot advised that the brake problem did not affect the selection of landing direction. It was considered that directional control was lost during the attempted go around, when the aircraft was affected by a wind gust at a critical stage of the flight.

Circumstances:

The pilot reported that during a landing on a road, and an attempted go-around, he was unable to prevent the aircraft veering to the left and colliding with a tree and a fence. The flare for landing had been commenced early resulting in a low forward speed and high nose attitude on touchdown. The pilot was only able to see the road through his side window, and it is believed that the slope of the road was a major factor in the loss of directional control.

Circumstances:

Shortly after DEPARTURE the pilot received an unfavourable weather report and decided to return to the DEPARTURE strip. The wind at the strip was estimated at 280/15 and the landing direction was 300 degrees. As the aircraft was about to touch down a sudden wind gust lifted the nose and left wing. The pilot recovered to a wings level attitude but the aircraft was then heading 30 degrees to the right of the landing direction. The aircraft collided with two low hawthorn bushes, coming to a stop a short distance further on facing opposite the landing direction.

The aircraft was stolen by a person with the intention of travelling to Western Australia. The ignition lock was activated using the frame of a pair of sunglasses, and after starting the engine the pilot taxied the aircraft onto the strip, where he commenced to take off downwind. Shortly after the aircraft became airborne the tail struck the ground, and the pilot reduced engine power. The nosewheel then contacted the ground and the aircraft commenced to "wheelbarrow". It ran off the side of the strip and subsequently overturned. There is no record of the pilot ever having held a flying licence, or of having received any formal flying training.