Circumstances:

After becoming airborne the aircraft was climbed steeply in order to clear a 15 metre high powerline. As the aircraft cleared the powerline the passenger indicated that he wanted to proceed towards the left. The pilot turned the aircraft sharply and, as he did so, he noted a decrease in main rotor rpm. The pilot continued the left turn, until he was pointing towards a clear area, opened the throttle, lowered the collective control and dived towards the ground in an attempt to regain the lost rpm. The attempt was unsuccessful and the pilot elected to land. He raised the nose and increased collective pitch in an attempt to cushion the touchdown. The pilot's actions caused the main rotor blades to enter an overpitched condition and the aircraft touched down heavily.

One skid collapsed and the main rotor struck the fuselage and the ground. No evidence was found that would indicate that the aircraft systems or components contributed to the accident. The steep climb out, to clear the powerline, required the pilot to use most of the excess power available. When the pilot entered a sharp left turn the additional aerodynamic load caused the main rotor rpm to reduce. There was no known reason why the pilot elected to turn abruptly under the particular circumstances. It is probable that the pilot, who had considerable experience on helicopters with low inertia rotor systems, expected the rpm to recover without difficulty. As a result, he misjudged the height and performance change required and was forced to make a rushed decision to convert his attempt at rpm recovery to a landing.

Significant Factors:

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

1. The pilot carried out an abrupt manoeuvre, which resulted in a decrease in rotor rpm.
2. The pilot misjudged the performance change required to recover from the low rpm situation.
3. The excess rotor performance available was insufficient to cushion the landing.

The pilot was carrying out a spray run near the edge of a cotton crop. He was aware of a powerline crossing his intended flight path and had originally intended to fly over the powerline. At the commencement of the spray run he sighted the pole from which the wires were suspended. The pole was close to the edge of the crop, and assessing that there would be adequate clearance, the pilot decided to fly beneath the wires. However, as he neared the wires he lost sight of them due to poor background. The pilot descended the aircraft as close to the crop as possible in an attempt to sight the wires, and to gain maximum possible clearance. The wheels entered the crop and caused the aircraft to decelerate. The pilot was unable to prevent the aircraft from settling into the crop. The aircraft came to rest after tipping onto its nose and ground looping.

Circumstances:

During the day the pilot, who was at Boulia, had arranged to conduct a charter flight from Bedourie to Boulia. He had earlier been seen drinking beer with a friend in a hotel, but he then conducted the outward leg of the flight, arriving at Bedourie at about 1830 hours. The passengers had expected to make the flight to Boulia the next day, but the pilot was insistent that the flight would take place that evening. The reason for the pilot's decision was not known, however, Civil Aviation Regulations prohibit charter passenger operations at night in single engine aircraft. The aircraft departed at last light. At about 2045 hours an aircraft was heard overhead Cravens Peak Station, which is 115 kilometres west of the track between Bedourie and Boulia. Station lighting was turned on, and the strip was illuminated with vehicle headlights. The aircraft did not have any navigation lights illuminated and was seen to make several low passes before it then disappeared. At about 2130 hours the aircraft reappeared at Cravens Peak, and was seen flying very low, parallel to the strip. The strip was again illuminated with vehicle headlights, but the aircraft disappeared from view in a southerly direction and did not reappear. At the time, a line of active thunderstorms was visible to the north of Cravens Peak, and there was a 25 to 30 knot easterly wind at ground level. Early the next morning, the aircraft wreckage was discovered 730 metres south-south-west of the homestead. It had struck the ground during a shallow descending turn to the right. The sounds of the impact were not heard by station residents, probably due the noise of wind. The reason for the gross navigational error could not be established, but the pilot was subsequently found to have a high blood alcohol reading, which could have significantly impaired his ability to conduct the flight safely. There were no aircraft defects found which may have contributed to the development of the accident.

Significant Factors:

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

1. The pilot attempted an operation which was in contravention of published regulations.

2. The pilot became lost during the flight.

3. The pilot had consumed alcohol before the flight, which could have impaired his ability to conduct the flight safely.

During the approach, the aircraft gear struck a set of three power lines. The pilot said that he misjudged the clearance over the second set of power lines located at the north-western end of the strip.

The aircraft was operating a freight carrying flight from Alpha to Barcaldine. Weather conditions at the destination were such that it was necessary for the pilot to conduct an instrument approach. He reported that he elected to leave the extension of the landing gear until after the completion of the approach. He further stated that he completed the prelanding checks but does not recall observing the gear position indicator lights. The aircraft was subsequently landed on runway 01 with the landing gear retracted. An inspection of the aircraft did not reveal any fault with the landing gear system that could have contributed to the occurrence. The pilot believes that he was distracted during the approach and landing sequence by the operation of the radio and the need, because of a 20 knot crosswind on runway 01, to decide on which runway to land. This accident was not the subject of an on-site investigation.

Circumstances:

The pilot stated that while in the cruise at 3500 feet, approximately ten minutes after take-off, the engine began to lose power and run roughly. Remembering that he had flown over a cleared area a short time before, the pilot elected to attempt to return to this clearing. During the descent he noticed that even with the throttle closed a rough vibration was being transmitted through the airframe. A decision was then taken to make a power-off landing. Approximately ten metres into the landing roll the right main wheel assembly separated from the strut when it impacted a small gully. The aircraft then came to halt without further incident. The investigation revealed that the piston assembly in the number five cylinder had failed due to prolonged and severe detonation. The exact cause of the detonation was not determined.

Significant Factors:

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

1. The number five piston assembly failed due to severe and prolonged detonation.

2. The aircraft was forced to land in unsuitable terrain.

The pilot reported that he was returning to a newly graded hard black soil strip at a muster camp. As the aircraft was turned at the end of the landing roll the nosewheel entered a pothole, causing the nosewheel yoke to break. The nose of the aircraft dropped and the tips of the propeller were bent on contact with the strip surface. This accident was not the subject of an on-site investigation.

The pilot was carrying out circuits and landings. Following a touch-and-go landing, the pilot had just reduced power at about 200 feet above ground level when the engine failed completely. The pilot turned the aircraft back towards the runway. After completing the turn, he realised he was too high and fast, with a 15 knot tailwind, to land on the runway. Sighting a paddock to his left, he made another turn back into wind toward it. The aircraft sank heavily onto the ground inside the aerodrome boundary, ran through a fence, and bounced back into the air. It then passed underneath a set of power lines, floated across the New England Highway and a second fence, and landed in the paddock, coming to rest some 365 metres from the initial touchdown marks. No fault was found with the aircraft engine or systems. The aircraft had carried sufficient but minimum fuel for the flight and it was considered that during manouevring a tank outlet may have become uncovered, resulting in fuel starvation to the engine.

On the first approach to land the aircraft was caught by a wind gust and the pilot carried out a go around. On the second approach the aircraft touched down and bounced. On the subsequent touchdown the aircraft was struck by another gust the left wing lifted and the aircraft tipped onto its nose and right wingtip. It then fell back onto its wheels veered to the left and ran off the runway. The wind strength at the time was reported as being 15 to 20 knots with gusts. The crosswind on the runway in use averaged 18 knots with a maximum of 25 knots. Local terrain features also caused variable wind problems. The into-wind runway was not available as it was being used for aircraft parking for visitors to an air show. The maximum crosswind component for the aircraft type was listed as 15 knots. The pilot was relatively inexperienced and had not previously landed in similar wind conditions.

During the takeoff roll, witness evidence suggested that the right mainwheel tyre had blown. The pilot requested a low pass for an inspection of the gear and it was determined that the complete right mainwheel was missing. After reducing fuel weight to a minimum by burnoff, the pilot carried out a wheels-up landing on the runway which had been foamed in advance. Subsequent on-site inspection by the Civil Aviation Authority airworthiness staff determined that four adjacent mainwheel tie bolts had failed due to under-torquing. The resulting play in the wheel halves then caused the mainwheel bearing to fail followed by the stripping of the remaining tie bolt nuts and the complete separation of the outer half of the mainwheel and the tyre. The last periodic inspection of the aircraft was completed just prior to the accident flight.