During the landing roll the aircraft started to veer right. The pilot under check applied sufficient rudder to correct the swing but then applied excessive left rudder and considerable power and the aircraft swung sharply left. The left wing and elevator tips contacted the ground whilst the instructor was regaining control. The pilot under check had not flown a tail wheel aircraft for five months.

Circumstances:

The pilot was conducting mustering operations and had the aircraft configured with 10 degrees of flap. While manoeuvring in a tight left turn at about 100 feet above ground level, the aircraft suddenly flicked inverted and had rolled through almost 360 degrees when it struck the ground. The pilot had about 40 hours mustering experience. This accident was not the subject of an on-scene investigation.

Circumstances:

The pilot had previously experienced difficulty with directional control on landing. He had been given additional training in crosswind landing techniques on the day prior to the accident and had performed to a satisfactory standard. On the subject flight, the pilot carried out a normal approach and touchdown with a slight crosswind from the right. During the ground roll while still travelling at about 25 knots, the pilot lost directional control and the aircraft ground looped to the right. During the ground loop the left wheel broke off and hit the left wing strut.

Circumstances:

The pilot had been operating in support of mustering operations and had landed a number of times to liaise with the mustering party. The pilot advised that he refuelled to full tanks from a drum that morning, but he was confused as to the fuel capacity of the aircraft as the figure " 98 litres " was written near each tank cap. During the return to the mustering yard the engine failed, and power could only be restored momentarily before a forced landing was necessary. The aircraft touched down in scrubland, collided with a stump and subsequently overturned. Discussions with the pilot revealed that he had not kept an accurate check on his fuel usage and had overestimated the endurance.

Circumstances:

The owner pilot carried out a pre-flight check of the aircraft, which included a check of the fuel for contamination. The aircraft had last been refuelled at Maitland, prior to the flight to "Roeta". The weather was reported as fine and clear, with a temperature of about 35 degrees Celsius. The wind was from the southwest at about 5 knots. The gravel strip was level and estimated to be about 3000 feet in length. The pilot said he used the strip on numerous occasions over the past 10 years in this, and other aircraft. Take-off was conducted into wind, using the full length of the strip. Although engine power indications and acceleration appeared normal, the pilot said he was aware that the aircraft appeared to require a greater distance to reach take-off speed. He attributed this to the outside air temperature. At an indicated airspeed of 60 knots, with inadequate strip length remaining to safely abort the take-off, the aircraft was flown off the ground. This was followed by an immediate and complete loss of engine power. Maximum flap was extended and the aircraft landed on the strip remaining. The aircraft continued beyond the strip end, across a road and associated table drain, before coming to rest. Although the reason for the loss of power was not established, water contamination of the fuel is considered by the pilot to be a strong possibility. The aircraft is fitted with bladder type fuel cells which can harbour water not easily detectable. The aircraft had had little use over the previous three months, during which time it had been parked in the open on level surfaces. On the two days prior to the accident the aircraft had been parked on a slope. It is considered by the pilot that water could have migrated from low points in the fuel cells to a position where it may have been ingested by the engine, resulting in a sudden loss of power.

During the pre-take off checks the student found the carburettor heat control could be pulled out further than usual and that there was no rpm drop associated with the application of hot air. On take-off the aircraft was slow to accelerate. It became airborne and was observed to enter a gentle right turn. A wing dropped and the aircraft impacted the ground. Investigation revealed that due to excessive wear, the carburettor heat control cable had failed at the attach point with the actuating bellcrank. The air hose between the muffler and the carburettor hot air box had collapsed internally. The combination of the carburettor heat control failure in the "hot" position and the obstruction of the alternate air source led to the loss of engine power during take-off. Shortly afterwards the aircraft stalled over flat open country.

In the pre-take-off briefing the instructor advised the student that during the flight they would conduct an inspection of the power lines crossing the Herbert River. The student subsequently flew the aircraft, in accordance with the instructor's directions, at about 100 feet above the river. The instructor was aware of four power line crossings. After passing the first, and when en-route to the second, the pilots heard a scraping sound and the aircraft slowed. Despite the attempts of the pilots the aircraft nosed down and subsequently struck the surface of the water at a shallow angle. Investigation revealed that the aircraft had collided with a power line, the presence of which was unknown to the instructor and had not been seen by either pilot. One of the supporting poles was obscured by trees, while the other pole was located approximately 350 metres across the river in a sugar cane plantations. All the wires were estimated to be 100 feet above water level.

Circumstances:

The pilot had previously undertaken a dual instructional flight during which he received instruction in, and practised, approaches simulating a jammed tail rotor pedal control. The pilot was then authorised for a solo flight which was to include practice of "jammed pedal" approaches. During one such approach, the skids contacted the ground while the helicopter was not in straight, balanced flight. The helicopter rolled onto its side in an uncontrolled dynamic rollover. Following the accident, the flying school amended its operations manual to preclude solo students practising "jammed pedal" approaches and landings.

Significant Factors:

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

1. The student pilot misjudged the height of the skids above the ground.

2. The helicopter was not in straight, balanced flight.

After touchdown, the pilot applied gentle braking but believed the aircraft was not decelerating. To avoid running off the end of the strip he attempted a ground loop, however, the aircraft ran off the side of the strip and struck a derelict vehicle. An inspection of the aircraft did not reveal any pre-existing defect that could have contributed to the occurrence. It is probable that the pilot misjudged the speed of the aircraft and the distance to the end of the strip when applying the brakes during the landing roll. He was not wearing the sash component of the seat belt and received facial injuries when he struck the control column during the collision with the vehicle.

Circumstances:

During the final approach over a station dam, the helicopter lost height suddenly in a strong down draft. The right skid hooked under a power line which resulted in the loss of control of the helicopter which crashed upside down at the water's edge. A strong South-Westerly wind pattern was established over the area. The approach path was downwind from a stand of large trees.