The pilot was using his aircraft for agricultural operations on his own land. The aircraft had been performing normally during the day, however on this particular take-off the engine lost power when the aircraft had reached about 55 knots. There was insufficient strip length remaining for the pilot to stop the aircraft, which struck several fences before coming to rest in a ditch 50 metres beyond the end of the strip. Despite an extensive examination of the engine and associated systems, the reason for the power loss could not be determined. However, several months later the engine again failed during a take-off run. The fuel valve was dismantled, and it was found that rivets holding a teflon insert in place had corroded and fallen off. Corrosion products had then jammed the insert in a position where fuel flow was reduced by about 25 percent. A backing plate had also become dislodged and was free to move around the fuel valve. It was probable that this plate had blocked off the fuel supply to the engine during the attempted take-off.

Shortly after touchdown, the gear unsafe warning horn sounded and the red gear unsafe warning light began to flash. The right wing slowly lowered and the aircraft veered to the right of the strip before coming to rest. An inspection revealed that the right maingear had collapsed because of the fatigue failure of the maingear side brace attachment stud. The fatigue cracks on the stud initiated in rough machine tool marks in the radius between the shank and the lug.

Circumstances:

The pilot had held a Private Pilot Licence for several years, for conventional aircraft only. He bought the gyroplane as a kit and assembled it late in 1988. His brother later bought a similar kit, and this was mostly assembled by the pilot. In the period 31 January-2 February the pilot received 3.5 hours of dual instruction in a two-seat version of the type. The flights consisted of take-offs and flights along the strip. No circuits were carried out. The instructor assessed that the pilot was tending to overcontrol the aircraft and recommended additional training. There was no evidence to indicate that the pilot carried out any further flying. On the day of the accident the pilot carried out a series of taxy runs and short hops along the strip. Following these he flew about six separate circuits, climbing to about 100 - 120 feet, landing and taxiing back to the start point on each occasion. The pilot's brother's machine had never been flown and the pilot suggested that he fly it for him. Two take off runs with brief lift off and landings were made. The pilot then flew several circuits and landings. Late on downwind on the final circuit the aircraft started to porpoise, with increasing amplitude. On about the fourth of these the nose went down, and the aircraft subsequently struck the ground in an inverted attitude. Inspection of the wreckage did not reveal any signs of pre-existing defects. For operation of these machines, it is necessary to ensure that they are flown under a positive gravitational loading. If this is not done the aircraft quickly becomes uncontrollable and may turn upside down. The porpoising manoeuvres seen just before the accident are known to lead to a negative gravitational loading situation if not quickly corrected. Advice provided to the investigation was that the appropriate control action was to reduce engine power to idle and hold the control stick central. In his limited training the pilot had not progressed to the stage of having the recovery technique demonstrated to him. It is possible that with his low experience level he may not have appreciated the dangers of the porpoising situation. While the machine in the accident and the one owned by the pilot were similar, there were some differences. The pilot's own machine was fitted with fairings, a windshield and a horizontal stabiliser. Persons experienced in the operation of gyroplanes consider that with a horizontal stabiliser the machines are more stable and less susceptible to porpoising and negative gravity situations.

Significant Factors:

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

1. Pilot did not obtain sufficient training on gyroplane operations.

2. Aircraft had different design and therefore, different flight characteristics to model previously flown.

3. Probable onset of porpoising, precise reasons undetermined.

4. Pilot unable to regain control possibly due to lack of knowledge and/or experience.

The aircraft touched down 385 metres into the 675 metre long paddock. The pilot reported that he applied the brakes but that they were ineffective. He decided that insufficient area remained for a successful go-around to be carried out and attempted to steer the aircraft through a gate. The right wing struck the gate and the aircraft turned through 190 degrees before coming to rest. The brakes were checked and found to be serviceable. The pilot stated that after touchdown he held the nosewheel on the ground and did not retract the flap. This would have had the effect of reducing the weight on the mainwheels and could have contributed to the reported brake ineffectiveness. The landing technique used by the pilot on this occasion was contrary to the technique recommended in the Pilot's/Owner's Handbook.

During the flight the groundspeed of the balloon increased to an estimated 12 knots, and the pilot decided to land in a showground. This area was surrounded by large trees. In the final stages of the landing attempt, the balloon was affected by a windshear and began to sink. The pilot activated the burners but the balloon struck a 15 metre high tree. Fearing that the balloon would overshoot the planned landing area, the pilot activated the rip panel. A heavy landing resulted and the basket rolled over in the direction of flight. One passenger was thrown from the basket and received a broken leg.

Prior to departure the aircraft received an airways clearance requiring it to track on the 151 radial from Cairns Visual Omni Range (VOR) beacon and cruise at flight level 210. The pilot accepted this clearance and taxiied the aircraft for takeoff from runway 15. He further requested approval to takeoff from a position 1065 metres along the runway. From this position 1531 metres of runway remained, sufficient for the operation. Before issuing a takeoff clearance to the aircraft, the Cairns Tower Controller instructed the pilot to maintain the aircraft at 2000 feet after becoming airborne. This instruction was to facilitate separation with an Boeing 737 aircraft, inbound on the reciprocal track, that had been instructed to descend to 3000 feet. To enable VH-AWU to be cleared to a higher level it was necessary for the controller to obtain advice from the pilots of both aircraft that they had passed each other. Following the takeoff of VH-AWU no departure report was received from the aircraft. The pilot of VH-AWU stated that because he was unable to break into transmissions between Cairns Tower and various other aircraft operating on the frequency he called Townsville Control on another frequency to obtain a clearance to climb. Townsville Control was unaware of the traffic situation in the Cairns area and was therefore unable to clear the aircraft to climb. At about the same time the pilot of VH-AWU was calling Townsville Control the Cairns Tower controller was calling the Boeing aircraft to ascertain whether that aircraft had passed the outbound VH-AWU. On being told by the pilot of the Boeing that the aircraft had passed the controller attempted to confirm the passing with the pilot of VH-AWU. However, the controller was not able to contact that aircraft, probably because the pilot was communicating with Townsville. The pilot of VH-AWU then contacted Cairns Tower requesting an immediate climb. The Cairns controller asked the pilot had he passed the Boeing, The pilot replied that he required an immediate climb "before I hit a hill". VH-AWU was cleared to climb to Flight Level 210. At the time VH-AWU was cleared to climb to Flight Level 210, the aircraft was near to the boundary of the Cairns Control Zone and about to enter a valley with hills on either side above the level of the aircraft. The visibility was reported to have been 30 kilometres and there is no reason to believe that the pilot would not have been able to successfully steer the aircraft down the valley visually. Several other options were also available to the pilot to maintain his aircraft clear of terrain. It is a function of Air Traffic Control that where an aircraft has planned for flight in controlled airspace, as was the case with VH-AWU, that the clearance issued to the aircraft should be aimed to keep the aircraft in controlled airspace. If it is not possible to issue such a clearance aircraft can be delayed or the pilot asked if he will accept a clearance which will take the aircraft outside controlled airspace. In this case while the intent of the controller was to keep VH-AWU in controlled airspace, the clearance issued was such that, with the expected performance of the aircraft, there was no guarantee of achieving that aim. It is considered probable that other clearances could have been issued to both VH-AWU and the Boeing which would have achieved the required separation and been less restrictive to the operation of VH-AWU.

The aircraft had been chartered to transport the passengers to Cooranbong for the day. The pilot had not previously operated into the strip and prior to DEPARTURE he enquired of another operator as to the suitability of the strip for his operation. He determined that the strip was suitable. On arrival in the circuit area the pilot assessed that the wind direction was swinging between 170 and 210 degrees and the velocity was gusting between 10 and 20 knots. The pilot elected to land the aircraft on runway 17. The pilot reported that when the aircraft was on short final it was affected by windshear. The aircraft touched down heavily, short of the runway sealed surface, continued along the ground for 7 metres before the mainwheels struck a low earth bank. Both propellers struck the ground momentarily as the aircraft continued onto the runway. The strip is located in hilly, tree covered terrain and at times is adversely affected by windshear. Two local pilots reported that at about the time of the accident adverse wind conditions did exist.

The pilot had been engaged to spray a stubble field for Noogoora burr. After flying to the property to be sprayed and loading the required chemical the aircraft took off, about 30 minutes after sunrise, to commence the first spray run. The pilot had chosen to fly the spray runs into the east, although on the only other occasion he had sprayed the field the runs had been made into the west. About 110 metres after commencing the spray run the aircraft collided with a branch of a dead tree and struck the ground. A small fire started and witnesses reported that the aircraft appeared to explode. The tree was the only obstruction in the field and it is probable that it would have been difficult for the pilot to see because of the rising sun.

The pilot had intended to go fish spotting in his aircraft. At about 1730 hours the aircraft was observed flying at about 100 feet above ground level and heading towards Streaky Bay. No further sightings of the aircraft were reported and when the pilot failed to return home a search was commenced. The wreckage was subsequently located the following morning. The aircraft had impacted in light mulga scrub in a steep nose down attitude. Investigation revealed that the main body tube had suffered an in-flight failure due to metal fatigue. The point of failure was at a junction of the rear engine pylon brace and the body-tube. The fatigue cracking initiated at rivet holes on the upper surface of the body-tube, beneath a doubler in an area which could not be visually inspected. The manufacturer had identified this problem and issued a mandatory inspection directive for this part, but the subject aircraft had not been inspected. Although the pilot was advised of this requirement by a friend, it is unlikely that he received any formal notification of it from the manufacturers local agent.

The first take-off attempt towards the South was abandoned because the pilot was uncertain whether the aircraft would become airborne in the distance available. He noted that the windsock indicated calm conditions, and after completing another engine run, elected to take-off towards the North. However, the windsock was sheltered from the prevailing wind and did not indicate the five to seven knot tailwind existing for the initial part of the takeoff. Full power was applied before the brakes were released, however acceleration appeared to be uneven, reducing as the wheels passed through soft areas on the strip. The aircraft struck a fence shortly after lift-off, and touched down in a nose-high attitude. It then bounced several times, struck a mound of sand and debris, and overturned. The investigation established that with the tailwind and soft wet surface conditions existing at the time there was insufficient runway length available. The pilot recognised the slow acceleration of the aircraft, but delayed his decision to abort the takeoff attempt.