The pilot had limited experience on Cessna 182 aircraft. He planned to carry out some practice circuits at the local airfield. All of the pilot's recent flying had been completed at a licenced aerodrome with a sealed runway. The local airfield consisted of a grassed area with a narrow gravel band running through the middle, and it was on this gravel area where takeoffs and landings were to take place. On the first approach to land, full flap had been selected for a normal landing. As the pilot raised the nose for landing, he over-rotated and allowed the aircraft to climb slightly. When he realised his mistake, he immediately lowered the nose. However, the nosewheel touched down heavily before the resulting descent was detected and arrested. The aircraft bounced a number of times before stopping on the gravel section of the strip. The pilot's restricted experience had not prepared him adequately for operations onto a "bush strip". The narrow gravel band in the centre of the strip was on undulating ground. There were trees close to the approach end of the strip and the surrounding area consisted of scrub. This presented the pilot with a set of visual cues on approach which were different to those to which he had become accustomed during his previous experience. The pilot had been used to closing the throttle over the end of the runway at the aerodrome where he had undertaken his training, and not well beforehand. As a result, the pilot's visual judgement of his approach profile became uncertain and he believed it would be necessary to fly a steeper approach and close the throttle prior to reaching the strip, a deviation from his normal procedure. After descending over the trees and once sure of reaching the strip he closed the throttle, and did not subsequently notice the airspeed. The aircraft was over-rotated at flare point, resulting in a balloon. This was followed by an over-correction downwards which in turn was followed by a hard touchdown and several bounces. A go-around was not attempted from the initial balloon, because the pilot felt that the nose attitude was too high and a go-around might have resulted in a stall. Although he did recognise that the approach was becoming unsafe, he elected to continue because he thought that if he took any different course of action he may have aggravated the situation.

The pilot was making a landing approach in moderate crosswind conditions. He commenced the flare at about 15 feet above the runway, with the intention of touching down in a three-point attitude. The aircraft sank rapidly, touched down and bounced to about 10 feet. The pilot maintained rearward pressure on the control column, but did not apply power. The nose of the aircraft dropped sharply and the propeller struck the runway. The aircraft subsequently overturned, coming to rest on the runway centreline. The pilot had completed a check flight on the aircraft the previous day. Conditions during the check flight were more demanding than those at the time of the accident. It was likely that the pilot relaxed his concentration as he flared the aircraft for landing, and was unprepared when the aircraft bounced and subsequently stalled.

The pilot was engaged in mustering operations at 100 feet above ground level and at 60 knots airspeed, when he heard a noise from the rear of the aircraft. He observed the rpm indicators split, with the engine rpm showing an overspeed, and he assumed a clutch cable failure. The aircraft was placed in an autorotational descent. As there was no clear landing area immediately available the pilot turned the aircraft into wind and attempted to find a clear area amongst the trees. The aircraft hit a tree, however, fell to the ground and rolled onto its side. The drive to the main rotors had become disconnected because the cable to the belt drive clutch control tension spring assembly had failed inside the assembly. The cable had been inspected for defects, and none were detected, at the last periodic inspection which occurred 59 hours prior to the accident. The cause of the cable failure could not be determined. The cable had been in service for 2210 hours. It is an "on condition" item, which does not have a specified life. The maintenance system for the aircraft requires that the cable be removed and inspected each 400 hours time in service. Removal is required to inspect the area on the cable that failed. The cable is inspected in situ each 50 hours time in service. The altitude and speed selected by the pilot gave sufficient performance potential for a safe autorotational landing, but the low cruise height significantly reduced the time available to locate and establish an approach into any suitable landing area.

Shortly after the pilot applied full power and commenced the take-off roll there was a loud bang and the aircraft yawed violently. The pilot closed the throttle and stopped the aircraft. An inspection disclosed that one complete propeller blade was missing. A detailed inspection of the propeller blade indicated that the blade had failed in the area of the threads at the root of the blade. The fracture surfaces indicated that a fatigue crack had started approximately 500 hours prior to the final flight and that the blade had failed because the remaining unaffected metal could no longer carry the loads involved. The inspection was unable to find any reason for the origin of the fatigue crack. The cracking occurred in an area of the blade which is not visible when the blade is fitted to an aircraft, consequently the cracking could not be disclosed during either preflight or periodic maintenance inspections carried out in accordance with the maintenance system in force at the time of the failure. The blades are normally inspected for cracks at each overhaul. An overhaul is carried out after the blades have been in service for 1500 hours. The blade that failed had been in service for 1052 hours.

While flying at approximately 150 feet agl on an instructional power line inspection, the instructor closed the throttle to simulate engine failure. The student turned towards a suitable paddock and commenced a practice forced landing. When it was assessed that the forced landing would have been successful the student was instructed to go-around. There was a minor delay in applying power during which time the aircraft continued to descend. The instructor then took control of the aircraft. The aircraft started to slowly gain altitude but due to the up sloping terrain and trees at the end of the paddock, the aircraft's rear fuselage collided with the trees. The instructor then closed the throttle and the aircraft settled into the trees. The student was a CPL holder and he had completed several low level forced landing practices. During these practices the student had always completed the go-around without difficulty. This fact influenced the instructor into allowing the practice forced landing to proceed to a lower level than would have been the case if the student had demonstrated some difficulty with the go-around. This expectancy that the student would perform the go-around without difficulty probably led to the instructor being slow to take over control of the aircraft in the very short time available to prevent the accident. The student was taken by surprise by the initiation of the practice engine failure. When a practice forced landing is started from 150 feet the whole exercise is compressed into a short time frame. This short time frame plus the additional work load from the practice emergency would have increased the workload on the student to a high level. The student believed that he heard the first command to go-around and started to increase the power, albeit slowly, but this is not supported by either the instructor or the passenger. The student was concentrating on successfully completing the forced landing practice and it is likely that a combination of channelised attention and high workload was responsible for the pilot not hearing the first command to go-around.

A descent from 3500 feet had just been commenced when the pilot heard a loud explosion. This was followed by a reported yaw to the right and the activation of several warning lights including the visual and aural engine fail warning. An autorotation was commenced and a Mayday call transmitted to Alice Springs Flight Service. The autorotational landing was accomplished between two sand dunes and on soft sand. During the landing the main rotor blades struck and severed the tail boom. The engine failure was initiated by failure of the first stage turbine wheel. The wheel fragmented when a fatigue crack in the wheel rim propagated to a depth of 4.85 mm (0.191 in.). There was no material deficiency or evidence of overheating in the blade root area. When the turbine wheel was fitted to the engine, cracks were noted in the wheel rim. It was estimated from a plot of fatigue striation spacings that these cracks were within acceptable limits as specified in Allison 250 DIL-190, which allows wheels with cracks in the rim less than 1.65 mm ( 0.065 in.). However, an inspection is specified after 500 hours or 500 cycles in service. Additionally, the manufacturer had calculated that the critical depth of this type of crack, beyond which failure may be imminent, was 15.4 mm (0.606 in.). The Operator's record keeping was deficient and the above inspection was not made before the wheel failed at 538 hours and 604 cycles. Had the turbine wheel been inspected at the appropriate time it is probable that the accident would have been avoided since the crack depth in the wheel rim must have been greater than that allowed in Allison 250 DIL-190. However, the turbine wheel failed after the fatigue crack had propagated only 4.85 mm which is well below the manufacturer's calculated critical depth of 15.4 mm. It is not known if the failure resulted from unusual circumstances or whether the calculated critical crack depth is in error. However, it is apparent that the critical crack depth for first stage turbine wheels should be re-assessed. The pilot executed an autorotational descent in accordance with the recommendations contained in the Bell 206 Flight Manual. The landing was normal for an autorotation but during the ground slide the pilot moved the cyclic control back as the helicopter approached some trees. The main rotor blades then severed the tail boom. The rearward movement of the cyclic control was a reflex type action rather than a deliberate control input.

The pilot was approaching the rear of a herd of cattle when he attempted to climb the aircraft. As he raised the collective control the engine RPM started to decrease. There was no suitable landing site below the helicopter so the pilot was forced to manoeuvre the aircraft around several trees to get to a suitable landing area. As he flared the aircraft for a landing the tail rotor contacted the ground and the main rotor severed the trunks of a tree and two saplings. The helicopter yawed to the left and slid sideways collapsing the left landing skid. The throttle control shaft output assembly, within the throttle control cambox had become dislodged, depriving the pilot of throttle control. The resultant freeplay within the throttle control system allowed the throttle butterfly to return to the idle position. The bearings and sleeves within the cambox are secured at manufacture by roll staking, which is considered to be the superior method for securing these components. However, the manufacturers maintenance instructions makes no mention of the method of securing the bearings and sleeves in the cambox. These components in the subject aircraft had been overhauled and were retained by the use of adhesive, which subsequently failed.

At about 500 feet above ground level after takeoff, just after the pilot commenced a left turn, the engine lost power. The pilot was unable to rectify the problem and chose a cleared area in which to land. During the approach it became obvious to the pilot that the aircraft would not make the selected area and he decided to land on a bush track. The aircraft touched down on the nosewheel and bounced, then touched down again before running through thick grass, coming to rest 74 metres beyond the second point of touchdown. A fire then broke out in the engine compartment, which subsequently destroyed the aircraft. The inspection of the wreckage was hampered by fire damage. However, a strip of the engine did not reveal any defects that may have contributed to the reported engine failure.

The pilot was manoeuvring the aircraft on the apron to park adjacent to another parked aircraft. Whilst making a right turn he was observing the other aircraft which was to his right, when the left wingtip struck a corner post of the airport boundary fence. The pilot had observed the fence post prior to commencing the turn and had assessed that there would be adequate clearance for the manoeuvre. However, he failed to continue monitoring the clearance with the post during the turn.

The pilot intended to position a beacon on the roof of the Perth Control Tower. The task was to be accomplished by sling loading the beacon, which weighed 199 kilograms, below the helicopter. The aircraft was positioned about 40 metres to the north and about 25 feet above the tower. The pilot carried out an approach to the roof and hurriedly deposited the load. The load was then released from the sling, which was left attached to the helicopter. The aircraft was then manoeuvred across the roof with the sling being dragged over the surface. The hook on the sling became snagged on the tower guard rail and halted the helicopter's progress away from the tower and causing it to pitch nose down and roll to the right. With the cable being tensioned by the pull of the helicopter the hook freed itself from the railing and the sudden relaxation of the load on the cable caused it to spring towards the helicopter. The cable flew up around the tail boom and became entangled in one of the main rotor blades. The other main rotor blade severed the tail boom which fell free of the helicopter striking the side of the tower on its way to the ground. The major section of the helicopter then fell to the ground at the base of the tower, caught fire and was burnt out. The tower roof was 90 metres above the ground and the baseplate, onto which the beacon was to be positioned, was triangular in shape with sides of about 60 centimetres long. Specialist opinion was that such a task would be difficult even under ideal conditions but there is evidence that a wind shear was present at about 300 feet at the time of the accident. The pilot's licence was not endorsed for sling loading operations and he was not sufficiently current on the aircraft type, considering its handling characteristics and suitability for sling operations, to undertake such a job. The ground crew were inadequately briefed about the job and their duties, and an inappropriate communication system between the ground crew and the pilot was used. The electric quick release for the lifting hook fitted to the helicopter was unserviceable although the alternate manual system was checked and found to be working. The pilot had recently been retrenched from his permanent employment and had not found other work. It is likely therefore, that he was excessively motivated to complete the task even though he was experiencing difficulty in accurately controlling the helicopter.