The pilot had made only one previous take-off from the Huskisson camp helipad. This was during an area familiarisation flight which he had conducted earlier in the day. Prior to the familiarisation flight he had not flown a Bell 47 series aircraft for several months. The aircraft load on take-off consisted of two passengers and 35 pounds of baggage and freight. The temperature was about 18 degrees centigrade and a light north-easterly breeze gave a tailwind component of 3 to 5 knots in the take-off direction. The flight path after take-off was dictated by the terrain and lay across a heavilytimbered gully towards a saddle slightly higher than the pad. During the lift-off and initial hover the engine operation appeared normal. Because of the tailwind an increase in power became necessary during transition to forward flight. After travelling about 100 yards, during which time he applied full power, the pilot decided that the aircraft would be unable to clear the trees ahead. He turned back towards the take-off point and, when it became apparent that the rotor speed was decaying, continued the turn and allowed the aircraft to settle towards a partly-cleared area at the bottom of the gully. At a height of about 40 feet, the main rotor struck the surrounding trees. The aircraft fell heavily to the ground and burst into flames on impact.

The aircraft had been re-built during April, 1968 and a maintenance release inspection had been carried out on 30th August, 1969. The aircraft had flown 129 hours since the re-building and had done 140 landings. At the time of the accident it had flown some 35 hours since the issue of the maintenance release. The aircraft was engaged in a period of circuits and landings and after touching down on the fourth landing, the pilot-incommand took over the controls in order to demonstrate crosswind technique. He applied full engine power for a go-around and at a speed of about 40 knots the starboard undercarriage leg collapsed, the nose of the aircraft dropped and it slewed to the right. The aircraft came to rest on its nose and starboard wing heading some 90 degrees to the right of the intended take-off path. The undercarriage had collapsed because of the fatigue failure of the lug of the eye bolt supporting the upper end of the starboard radius rod. Examination showed that the pivot bolt and probably the eye bolt itself had been tightened to an extent which prevented the pivotal movement of these components and an abnormal load would therefore have been imposed on the eye bolt lug during ground operation of the aircraft.

The pilot, who was not licenced, did not ensure that the design, construction and maintenance of the aircraft, and the manner in which it was operated, met standards which provided an adequate margin of safety.

The pilot had never received any formal flying training. He did not hold a pilot licence and it is probable that he did not meet the medical standards laid down for the holders of such licences. He had flown gyro craft over a period of 4 years and on the day of the accident he was flying a self built, unregistered, unapproved aircraft of the type within the close environs of the airstrip. His own sets of rotor blades were unserviceable and he had fitted a borrowed set of wooden blades which he had not previously used. The performance characteristics of this set varied from his own blades and were significantly different to a set of borrowed metal blades he had used exclusively for some months before the accident. He flew for 30 minutes on a series of brief flights, adjusting the tracking of the borrowed blades and when he was satisfied that they were tracking accurately, he took off and then made a low run along the airstrip. The aircraft then climbed to a height of about 70 feet, turned to the left through some 250 degrees and straightened when it was headed obliquely towards the centre of the strip. The manoeuvres were controlled, were made at a slow speed and were consistent with the flying habits of the pilot. Soon after the turn was completed there was a noise similar to an engine backfire, a puff of smoke or vapour appeared and the craft entered a steep nose down descent. The descent angle was reduced, but recovery was not effected before the aircraft impacted heavily on an upslope.

On 20 November, 1970 a Cessna 320D "Skyknight" aircraft, registered VH-CPP, disappeared on a flight from Bankstown, New South Wales to Coolangatta, Queensland, and no trace has been found of the aircraft or its two occupants.

Search operations commenced early on the morning of 21 November and continued for 6 days, during which helicopters and fixed wing aircraft flew a combined total of more than 203 hours. Numerous sighting and hearing reports were checked by aircraft and ground parties but no trace has been found of the aircraft or its occupants.

The pilot planned a flight from Bankstown to Wollongong and return with landings at Sydney and Camden en route. The aircraft touched down in an open grassed area 500 feet beyond the airport fence and slightly to the left of the extended centre line of the runway. The nose landing gear was torn off as the aircraft ran across a ditch 30 feet after touching down. The aircraft slewed to the left through 150 degrees, both main landing gears collapsed, and the aircraft came to rest in a level attitude 114 feet from the point of touchdown.

Whlie the aircraft was in flight at some 3000 feet above the Hawkesbury River, the VHF communications radio failed. After a few moments the pilot was aware of a smell of burning and he switched off the radio. Shortly after the radio was switched off, pungent smoke originating from the area of the radio installation under the instrument panel began to enter the cockpit and the pilot was compelled to open the canopy. He decided to land immediately and commenced an approach to a fairway on the nearby golf course. The approach was high and fast and the aircraft overshot the fairway. The pilot lowered full flap at approximately 90 knots and after crossing a line of trees proceeded to land on another fairway. Prior to touchdown he turned off the ignition, fuel and master switch and warned his passenger to leave the aircraft as soon as it stopped. When on short final the pilot noticed some golfers near the far end of the fairway and he applied full brake and full right rudder before touching down. The aircraft made contact with the ground initially on the right wing tip, bouncing on to the main wheels and nose before falling back on to the main undercarriage and tail wheel. The total ground run was 180 feet. Subsequent bench testing of VHF radio equipment revealed that in the circumstances of the filter capacitor breaking down, the overheating of the filter inductor produced smoke from the insulating substance.

The pilot, who was the general manager of the irrigation property on which the accident occurred, and his passenger, who was the farm manager of the same property, were on an inspection flight to observe accumulations of water from recent rain. The aircraft circled and manoeuvred over various sections of the property at a height of about 500 feet for approximately fifteen minutes and was then seen to make a shallow descent towards the homestead buildings. It flew towards a position where two employees were working adjacent to the property workshop and at a height of some 28 feet while still approaching the workshop area, it struck power cables. The forward movement of the aircraft was retarded, it nosed up steeply, then rolled to the left and dived to the ground steeply nose down. Several seconds after impact, the aircraft burst into flames and was completely destroyed by fire.

The pilot had completed three flights, consisting of a boundary survey flight followed by two spreading sorties. The weather was clear and calm and the temperature approximately 40°F. The third spreading sortie was to be flown over a paddock of irregular shape, about 1 mile long and 300 feet wide, oriented north-west south-east. The paddock was bisected by a line of trees beyond which the ground sloped gently upwards towards a low hill located beyond the south eastern boundary. A witness standing near the north western boundary of the paddock watched the aircraft as it began spreading in a south easterly direction and then lost sight of it. Approximately one half minute later the sound of the engine ceased abruptly followed closely by a heavy impact. The aircraft was found to have struck the ground while in a nose down attitude of some 22 degrees with the right wing slightly low and at a location consistent with the aircraft having completed its spreading run and turning to commence its next run. The impact marks indicate that the aircraft was skidding to the right. The hopper doors were in the dump position and portion of the load had been jettisoned immediately before impact. The aircraft came to rest facing in a south westerly direction some 53 feet from the initial impact point. There was no fire.

The pilot completed the refuelling of the aircraft and pushed it back to a position approximately half way across the 100 feet wide apron. He applied the parking brake, carried out a pre-flight check and commenced the starting up procedure. He made two unsuccessful attempts to start the engine and then adopted the flooded start technique by setting the throttle to 3/4 open and the mixture control to "Idle Cut Off". When the engine fired on this attempt the pilot moved the mixture control to "Rich" but then found that he was unable to close the throttle, which had apparently jammed. The aircraft moved forward under high power, overcoming the parking brake, which was weak. Before the pilot was able to move his feet from their position on the floor and place them on the brake pedals, or take any of the other courses of action which were indicated, the aircraft had travelled forward some 60 feet to a position at which it struck a heavy wooden post and a steel stake on the fence line of the apron. Examination of the throttle control assembly did not disclose any defect which would have accounted for the inability of the pilot to control the engine power output, however, misuse of the throttle locking button could have led to a situation in which the throttle control jammed.

The crew of the aircraft comprised an Instructor, who was employed by the operator, acting as pilot-in-command in the right front seat and a private pilot, who was undergoing instruction on the aircraft for type endorsement, in the left front or normal pilot seat. The flight was also for the purpose of the private pilot visiting his father's property near Ardlethan on personal business. The third occupant was a student pilot who had not yet begun his flying training and had been invited on the flight as an observer. After arriving over its destination, where a strong south westerly wind of up to 20 knots was evident, the aircraft circled the airstrip and then flew across the homestead in a north easterly direction at a low height. As it approached a low ridge which crossed the flight path at right angles the aircraft began to climb at a progressively steepening angle until at a height of approximately 250 feet above the ground and at an obviously diminished airspeed it began a steeply banked turn to the left. At this point the aircraft nosed down and, at an angle of descent of about 50 degrees, dived into the trees near the base of the western face of the ridge.