The aircraft was observed approaching to land on Runway 21. It bounced on landing and then rocked from one mainwheel to the other before veering off the left side of the strip and running through a fence. The pilot reported that the wind was straight down the strip and that on touchdown the aircraft swung left suddenly. He was unable to control the swing. A witness on the ground reported that the wind at the time was from the south-east at 15-20 knots but favouring Runway 21. He saw the aircraft bounce a few feet before touching down again on one mainwheel and then the other and then veer off the strip. No fault was found with the wheel brakes which might have caused the swing. This accident was not the subject of an on-site investigation.

Circumstances:

The pilot was involved with a group of Venturer Scouts on camp in Tasmania. At the time of the accident, about 20 members of the group were involved in water skiing activities at Meadowbank Lake. The pilot had earlier arranged to make two scenic flights to Cox Bight in the State's south-west for members of the group. He had also told one of the scouts that he would fly past them at the lake. The lake was on the planned track to the south-west and the flight on which the accident occurred was the first of the two planned flights. The lake is approximately 13 kilometres long and lies generally in a north-west/south-east direction. The aircraft was seen approaching from the north-west over the lake at low level. It flew past the group which was located on the south-west bank of the lake. The occupants could be seen waving to those on the shore. Shortly after passing the group, the aircraft hit the top wire of a three wire powerline that was suspended across the lake at a height of about 12 metres above the water. The wire first impacted the left main wheel and then slid up the wheel leg. The wire broke at the poles from which it was suspended either side of the lake. It was then dragged some distance by the aircraft. The two poles were approximately 300 metres apart. The aircraft continued for about 500 metres before diving into the water. The powerline would have been very difficult to see from the aircraft. There were no hazard markers of any description on the powerline, and it would have blended into the background of cliffs on the edge of the lake.

Significant Factors:

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

1. The aircraft was flown on a low altitude across the lake surface.

2. The powerline would have been difficult to see from the aircraft.

The aircraft was engaged to spray pasture with insecticide. After a ground inspection of the treatment area, the aircraft was loaded, prior to its first take-off from the strip. Another company aircraft was also operating from the 800 metre long strip. Take-off direction was to the west, with a 2 uphill slope, and a 2 to 3 knot tailwind component. The first aircraft departed without problem. The pilot of VH-KNL, departing some three minutes later, reported that the aircraft's tail was slow to lift off the ground. Some 700 metres from the start of the take-off run, the aircraft encountered soft ground. The pilot selected 20 degrees of flap but this had little effect. The aircraft became airborne and he commenced to dump his load. The aircraft struck a ridge 30 metres from the end of the airstrip, bounced and came to rest on a second ridge 200 metres further on. The pilot reported that the engine had been operating normally, but that he had been late dumping his load, when the aircraft failed to perform. There had been insufficient strip remaining to abandon the take-off. This accident was not the subject of a formal on-site investigation.

On arrival overhead at the destination aerodrome, the pilot elected to land into a strong headwind on the grass strip. The nose landing gear failed when the nose wheel dug into the grass surface during the application of heavy braking, and the aircraft overturned. Investigation revealed that the approach speed had been higher than optimum for the weight, and skid marks on the strip indicated that a series of heavy brake applications had been made during the landing roll. The nose landing gear was inspected, and it was found to have fractured in torsional overload. It is considered that the combined effects of the aircraft not being flown at the optimum approach speed, the heavy application of brakes on a grass strip and the failure of the pilot to adequately compensate for the resultant pitch down of the nose contributed to the accident.

The aircraft was engaged on a coastal sightseeing flight in marginal VMC. The area was affected by a humid airflow. The pilot said the engine appeared to be affected by carburettor icing and, although he was able to restore power with carburettor heat, he was apprehensive about returning over the metropolitan area. He said he decided to make a precautionary landing on a nearby clearing. After a landing roll of about 100 metres, the landing gear struck a shallow ditch and collapsed. The aircraft slid to a halt a few metres beyond the point of impact.

The flight was a check for the pilot-under-instruction who had not flown since gaining a restricted private licence more than three months previously. This was also her first flight in a high-winged aeroplane. After some general handling practice, the instructor initiated a practice forced landing which was to conclude with a full stop landing on an authorised landing area (ALA). The pilot-under-instruction flew the aircraft with the instructor commenting as necessary. On late final, with full flap selected, the aircraft developed a higher than normal sink rate and subsequently contacted the ground in a right skid. This subjected the nosewheel leg to substantial sideloads, forcing it to the rear left and buckling the firewall. Late in the landing roll, the propeller and right wingtip contacted the ground. The instructor reported that he was aware of the high sink rate and placed his hands on the controls but felt that no control input was necessary as he had experienced landings from similar rates of descent many times. Had the aircraft been in balanced flight at touchdown, it is possible that no damage would have been sustained. Neither crew member reported hearing the stall warning operate. Conditions were such that the higher sink rate could have been induced by windshear.

For the ferry flight, the pilot placed an overnight bag on the passenger seat, leaned a swag and fuel pump against the seat and secured the lot with the seat belt. His pre-flight control checks revealed that full control travel was available for the collective and cyclic controls. During the climb the swag slipped and came to rest against the cylic control. At this stage it was not causing any control interference. The pilot intended to fly past the lee side of a mountain and found that the swag was now restricting movement of the cyclic pitch control. The seat belt was unfastened to reposition the swag. At the same time, the helicopter encountered some turbulence. The swag fell onto the collective pitch control lever, pushing it nearly all the way down. The helicopter descended out of control with both the cyclic and collective controls fouled. The pilot managed to regain partial control just before impact and, following the heavy landing, rolled the helicopter into a steeply sloping rock face. The pilot commented later that the critical point in the scenario was reached when he unlatched the seatbelt to fix an annoying, but not serious problem at an inappropriate time. This accident was not the subject of a formal on scene investigation.

The student conducted a normal take off and was climbing in a right turn at 50 knots and 200 feet above the ground when the engine rpm suddenly reduced by about 60 percent. The instructor immediately took over the controls lowered the nose adopted a glide attitude and began a left turn into wind by which time the airspeed had reduced to 40 knots. He then became concerned about a powerline in the area which he could not see. In an attempt to avoid this powerline he turned the aircraft to the right which was downwind but towards a suitable forced landing area. During the turn the airspeed reduced to about 35 knots and the rate of descent increased. At about 10 feet above the ground and with a tail wind of about 10 knots the aircraft was flared in an unsuccessful attempt to arrest the rate of descent. The aircraft struck the ground heavily bounced and then overturned. A subsequent examination of the engine revealed a damaged low tension ignition lead. This had the potential to short-out on the housing of the engine fuel pump thereby causing one of the spark plugs to become inoperative with an associated reduction in engine rpm. The damaged wire was probably the result of an earlier heavy landing.

The aircraft had been operating for two hours without any apparent problems. Shortly after lift off, following a refuelling stop, the pilot was unable to maintain directional control and the aircraft began yawing rapidly to the right. The pilot attempted to land the aircraft in a clear area, however, one skid dug in and the aircraft rolled over. A fractured tail rotor drive shaft intermediate flexplate was the only mechanical defect found during the investigation. The specialist engineering investigation established that the flexplate failure was caused by the main rotor blades contacting an external object. The only main rotor strike evident at the accident site occurred when the aircraft rolled over following the landing. Damage to the tail rotor control rods indicated that full left peddle had been applied at the time of the flexplate failure. Aircraft weight, power requirements, wind conditions and take-off and DEPARTURE techniques were not conducive to loss of tail rotor effectiveness, however, loss of tail rotor effectiveness will cause the aircraft to yaw to the right. The reason for the initial yaw was not determined. The aircraft rolled over when the pilot was forced to make an emergency landing on unsuitable terrain whilst he was attempting to recover from a difficult control situation.

The pilot reported that, while mustering an animal which had broken from the mob, one of the skids came into contact with the animal. This caused the helicopter to roll and strike the ground causing the tail boom to be severed and destroying the main rotor blades. The muster was being conducted in open country, with no trees in the area. The pilot had evidently allowed the aircraft to descend to an unsafe height during his attempts to return the particular animal to the mob. This accident was not the subject of an on-site investigation.