While enroute to the treatment area the pilot noted a loss of engine power. After the load of superphosphate was dumped, he realised he would be unable to return to the DEPARTURE strip and selected a track as the most suitable landing area. During the landing roll the aircraft ran over a hump which caused it to slew off the track into the surrounding bush. Engine examination revealed that the fuel injector system was out of adjustment, producing a lean mixture at high power settings. The resulting high combustion temperatures produced abnormal engine wear and led to spark plug failure.

Cattle were being mustered from open country with the helicopter operating at 15 to 20 feet agl in wind gusting to 25 kt. At the completion of one downwind run the trainee flared instead of turning into wind. The main rotor blades overpitched and the helicopter struck the ground heavily, tail down, before the instructor could recover control of the situation.

The pilot was making an approach to land at his private strip. Wind conditions were gusty and the aircraft was observed to be making a lower approach than was usual. In the vicinity of the boundary fence a substantial increase in engine noise was noted, and the aircraft was seen to be climbing steeply. After reaching a height of about 100 feet the aircraft rolled, descended steeply and struck the ground in an inverted attitude. The reason for the pilot making a lower than normal approach profile was not established. It was determined that the right wing of the aircraft had become entangled with the boundary fence. In an attempt to regain control the pilot had probably instinctively applied large corrective inputs. The fence wire then broke but the aircraft was in an airspeed and attitude configuration such that the pilot was unable to prevent a stall and consequent total loss of control.

The aircraft had previously suffered from aileron flutter and a new set of wings had been constructed and installed. Although the problem of flutter had been removed the aircraft then flew slightly right wing low. A trim tab was fitted and the subject flight undertaken to check its setting. Initial engine running and flight after take-off were normal until the aircraft was on the downwind leg of the circuit. The engine speed was heard to reduce and the aircraft settled into a glide descent. The left wing struck a tree and the aircraft landed heavily on its left wheel and wing tip. The wing separated at its root and the aircraft bounced, landing again on its left side 25 metres further on. Specialist examination of the aircraft indicated that the fuel primer bulb in the engine fuel line had a valve installed incorrectly. Under certain orientation conditions the valve could prevent an adequate fuel flow for continued engine operation. The fuel system layout was such that the position of the primer bulb could vary after handling between flights. As the engine was either stopped or running at idle power at the time of ground impact, the fuel flow is believed to have been restricted, causing engine fuel starvation. No other engine or airframe defects were found. Calculations showed that flutter would not have occurred in the re-designed ailerons and no evidence of flutter was found in the wreckage. When faced with a forced landing in moderately treed terrain, the pilot had misjudged his distance from a tree and was unable to regain control of the aircraft in the height available.

Approaching the destination, the pilot noticed that rain had recently fallen on the strip. The pilot stated that he overflew the strip but wished to ascertain the amount of rain that had fallen before attempting to land. He reported that an inspection run was conducted, however, a strong tailwind component existed and the resulting groundspeed was too high to enable an adequate inspection to be made. A procedure turn onto a reciprocal heading was carried-out, and the aircraft placed in the approach configuration. This inspection run was intended to be flown at a height of about 200 feet above the ground, and additional engine power was introduced as required to compensate for downdraughts. During the inspection the aircraft struck a power line about 20 feet above a road, and subsequently landed heavily on the sloping roadside. Information available at the accident site indicated that the pilot was either landing or preparing to land on the road.

At the end of a 180 deg turn the pilot attempted to level out but there was no cyclic response. The helicopter continued in the turn and the application of back cyclic could not prevent the nose dropping. The helicopter struck the bank of a creek shearing off the tail boom, main rotor and gearbox and came to rest in the water. The pilot escaped unhurt and unaided from the partially submerged cockpit. Investigation revealed that a bolt which secured a foot of the cyclic control wobble plate pylon to the transmission gearbox had become detached. Subsequent movement of the pylon deprived the pilot of effective cyclic control. The reason for the loss of the bolt could not be established.

Soon after settling in the cruise at 2000 feet, the pilot noticed that the fuel flow was lower than expected. He selected rich mixture but the fuel flow began to fluctuate markedly and the MAP reduced. A short time later the engine began to run roughly, accompanied by a rise in oil pressure and a further reduction in MAP. The pilot elected to return to the departure point. Engine power became inadequate for level flight and the pilot selected an emergency landing area. The aircraft came to rest after running through two barbed wire fences. The engine failed due to long term lack of lubrication to several bearings caused by the rotation of two main bearing shells which covered oil supply galleries. The damage to the main bearing assemblies was such that the cause of bearing shell rotation could not be established.

Circumstances:

During take-off, the pilot inadvertently allowed the engine/rotor rpm to decay. By the time he realised his predicament, the main rotor was overpitched and the helicopter slowly settled back towards the ground. With a loss of tail rotor thrust due to the overpitching, the pilot was unable to avoid the body of the helicopter rotating through 270 degrees. During the rotation, the tail rotor and main rotor struck a small tree. The helicopter landed heavily, spreading the landing gear skids.

On arrival at Macquarie Marshes the pilot flew several circuits of the strip and then attempted a landing in a small holding paddock nearby. During the flare the pilot assessed the paddock had insufficient length to complete a landing so he initiated a go-round. The tailwheel caught the top wire of a boundary fence which caused the aircraft to decelerate and hit the ground. The aircraft then collided with a second fence and came to a halt resting on the left wing. This accident was not the subject of a formal on-site investigation.

Circumstances:

Enroute from Lilydale to Melbourne the pilot was required to hold for a short time. While doing so he noted that the elevator control seemed heavy. He set 30 degrees of flap for landing and said he began to move the control column back to flare at about 65 knots. He said that the aircraft did not respond but that the nose dropped and the aircraft hit the runway nose wheel first and bounced several times. Later inspection of the aircraft did not reveal any evidence of pre-existing defects. The prevailing wind at the time of landing was from the south at about 12 knots. At around the time of landing the wind direction changed to 120 degrees at about the same strength. This wind shear effect may have contributed to the handling difficulties reported by the pilot during landing. This accident was not the subject of an on-scene investigation.