At about 400 feet above ground level, on climb out after takeoff, the engine suddenly lost power. The pilot was faced with landing on unsuitable terrain and as a result the aircraft was substantially damaged. The cause of the power loss was determined to have been spark plug carbon fouling due to an excessively rich fuel mixture. During previous maintenance by the aircraft owner, the mixture slide needle had been refitted incorrectly to the piston slide assembly. This positioned the needle about three millimetres higher than it should have been, resulting in the mixture being over-rich throughout the throttle range. This occurrence was not the subject of an on-site investigation.

Circumstances:

During a period of low operational activity, the pilot was contracted to spray a crop in open, flat terrain. Having almost completed the irregular shaped area, the pilot positioned his aircraft to make a run over a very small corner of the crop, towards a clump of trees, some of which were up to 25 metres high. The pilot mis-judged his turn onto the run alignment, necessitating a steep approach. Once settled at spray height, he was faced with a very steep climb-out to clear a large tree. During the pull-up, the aircraft stalled and collided with the tree. The nose pitched down, and the aircraft impacted the ground in a near vertical attitude, before rolling inverted. The pilot extinguished a small fire.

Significant Factors:

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

1. The pilot attempted to spray an area which was only marginally suitable for aerial treatment.

2. The pilot mis-judged his approach to the area.

3. The aircraft stalled during the pull-up.

Recommendations:

The Civil Aviation Authority reassess recency requirements for agricultural pilots to place emphasis on hours flown during the preceding 90 days. This assessment should take into consideration the type of operation the pilot is to return to following an extended break, or period of very low operational intensity.

The aircraft was being used for circuit training. During the third touch-and-go landing the left main gear separated from the aircraft. The left wing struck the runway and the aircraft slewed to a halt. Specialist investigation confirmed that one of the main gear retaining bolts was fatigued. Widespread surface corrosion was prsent on the shank of the bolt. The specialist considered that the initial fatigue fractures are corrosion related. Investigation revealed that this type variant is fitted with large wheels and that failure of the gear retaining bolts occurs more frequently with this variant than that fitted with small wheels. The occurrence was not the subject of an on-site examination.

The pilot had operated from the 750 metre strip many times, usually in a Britten-Norman Islander BN-2 aircraft. On this occasion, however, the BN-2 was not available so a PA23 aircraft was used. The strip was firm and covered with grass 10-15 cm long. There had been intermittent showers on the strip for some hours. Although the pilot had operated PA23 aircraft from the strip previously, he had not done so in wet conditions. The pilot held the aircraft on the brakes and set full power before beginning the takeoff roll with 10` flap selected. He reported being concerned part way along the strip at what appeared a slow rate of acceleration but put this down to the different characteristics of the PA23 aircraft compared to the BN-2. Further down the strip the pilot considered aborting the takeoff but decided to continue after concluding that there was insufficient strip remaining for the aircraft to be stopped. The aircraft became airborne about 20 metres from the upwind end of the strip and the left wing contacted vegetation a short distance further on. This slewed the aircraft left, resulting in the fuselage being broken just aft of the cockpit as the aircraft slowed and came to rest in mangroves. The takeoff performance chart for the aircraft indicated that the strip was of sufficient length for take-off under dry conditions. However, there was no information available to the pilot as to what allowance should be made for long wet grass conditions. In the event, the aircraft became airborne near the end of the strip, probably before the correct speed had been reached. This accident was not the subject of an on-site investigation and this report is based on information provided by the pilot.

The pilot was to spray weeds in four areas marked 1-4 on the plan of the property he had been given. He conducted an airborne inspection during which he noted a single power line, running east west, along the northern side of area 1. Adjacent to the power line was an area of seed lucerne which the property owner emphasised was not to be sprayed. Area 1 was immediately south of area 2 while areas 3 and 4 were some distance away and well clear of the power line. There was sufficient daylight remaining for the pilot to spray areas 3 and 4 and to partially complete area 2 flying runs parallel to the wire. That evening, there was some disagreement between the pilot and the property owner as to whether the correct ratio of chemical had been used, and the property owner again emphasised that he did not want any spray to fall on the seed lucerne. The following morning, without conducting a further aerial inspection, the pilot sprayed the remainder of area 2 and, while waiting for the markers to position themselves in area 1, he decided to do a clean-up run from north to south along the western edge of area 2. He recalled that, as he flew the run, foremost in his mind was the need to avoid spraying the seed lucerne. The aircraft struck the power line at the completion of this run. The wires became caught in the engine upper cowl and rolled the aircraft so that it impacted the ground right wing first. The right wing was torn from the fuselage as the aircraft cartwheeled. The pilot, who was wearing a helmet, received serious facial injuries in the accident. It was found that the left hand lap toggle in the safety harness buckle had failed on impact, allowing the pilot to be thrown forward and to the right into the instrument panel/coaming. Metallurgical examination showed that the toggle failed due to insufficient strength caused by inadequate heat treatment during manufacture.

During the preflight inspection, the pilot dipped the fuel tanks and noted that the left tank contained 25 litres and the right tank just on 30 litres. The airrcaft was taxied out to the run-up area using fuel from the left tank. Before the run-up, the pilot switched the fuel selector lever to the right tank and left it there for the take-off and remainder of the flight. The pilot decided to finish the flight with a touch and go landing followed by a final circuit. Following the normal application of full power for takeoff, the aircraft climbed to 100-250 feet above the ground when the engine surged and lost all power. The pilot chose a football field straight ahead and made a successful touchdown. Unfortunately, he was so engrossed with missing objects and steering the aircraft that he forgot to use the brakes effectively. The aircraft ran on and struck two goal posts and a tree before coming to rest against a security fence. The two occupants exited without injury. The engine had failed due to fuel starvation when all the useable fuel from the right tank had been consumed.

The flight proceeded normally after departure until about 1114 hours when the pilot noticed a decrease in engine RPM from 2500 to 2300. He opened the throttle but the RPM continued to decrease. As he was unable to restore power to the engine he turned the aircraft towards an open area, that had been overflown a couple of minutes earlier, and set the aircraft up in a glide. The area chosen was the only suitable area available for a landing. The pilot positioned the aircraft to join the downwind leg of the circuit and transmitted a "Mayday" call. As the aircraft was turned onto final approach the pilot spotted a six metre high tree near the intended touchdown point and manoeuvred the aircraft to avoid the tree. At this stage the flaps were selected fully down and the indicated airspeed was 75 knots. The aircraft subsequently floated for a considerable distance before touching down 453 metres after the first available touchdown point. The distance remaining to a fence at the end of the landing area was 309 metres. During the landing roll the right wingtip struck a small tree, as the pilot was attempting to manoeuvre the aircraft clear of an obstruction, and the aircraft was turned to the right. The right wing then struck a second tree which resulted in it being torn from the aircraft and the travel of the aircraft was halted. An inspection of the wreckage found that there had been an internal failure of one muffler which resulted in two of the four engine exhaust outlets being completely blocked.

Circumstances:

The student made a normal landing but as the aircraft slowed, the instructor noted the right wing was sinking and he assumed control of the aircraft. He held the wing up as long as he could and kept the aircraft straight without braking. The aircraft slowly veered to the right and came to rest off the sealed runway surface. The right hand landing gear wheel assembly had separated from the aircraft about thirteen metres after touchdown, with the result that the right hand flap, torque tube, aileron and stub of the landing gear cylinder were damaged by abrasion with the runway surface. The right hand landing gear strut had separated from the cylinder due to one of the two torque link securing lugs failing from fatigue, and the torque link retaining bolt failed due to overload. The main landing gear cylinder torque link lugs are subject to a visual inspection every 100 hours by aircraft maintenance engineers, but there is no existing requirement to inspect the strut torque link lugs.

Significant Factors:

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

1. The torque link lugs failed because of fatigue.

Recommendations:

It is recommended that the Civil Aviation Authority amend AD/PA-28/50 to incorporate dye penetrant inspection of the main landing gear torque link upper and lower mounting lugs.

Circumstances:

The aircraft was being winch launched on the pilot's second solo flight. Experienced observers on the ground reported that the take-off appeared normal, but soon after liftoff the aircraft adopted a steeper than normal nose up attitude. The pilot appeared to correct this to some degree but the aircraft continued to climb slightly steeper than normal. A video tape recording of the flight showed that, at a height of between four and five hundred feet above ground level, the tow cable broke. The nose attitude of the aircraft was quickly lowered to what appeared to be a near level flight attitude. A short time later, however, the glider rolled to the left and the nose dropped. The aircraft then spiralled through one and a half turns before impacting the ground. It would appear that, following the cable break, the pilot did not lower the nose sufficiently to maintain flying speed. As a result, the aircraft stalled and then entered a spin. The pilot had not experienced a tow cable break prior to this accident but had been instructed on the procedure to be adopted in the event of such an occurrence. The cable failure would probably have taken the pilot by surprise and this, coupled with his low experience level, could have contributed to the loss of control of the aircraft. These aspects could also have affected the pilot's ability to regain control of the aircraft.

Significant Factors:

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

1. The pilot's experience level was low.

2. The abnormally steep climb during the launch probably caused the tow cable to break.

3. The cable failure probably took the pilot by surprise.

4. The pilot lost control of the aircraft.

5. Control of the aircraft was not regained in the height available.

Recommendations:

During the investigation, it became apparent that cable failure training methods and standards varied across various gliding clubs. For example, the pilot involved in this accident had apparently received one simulated cable failure during launch. All his other training in this aspect was conducted in free flight at height under simulated launch conditions. At other clubs, students were exposed to simulated cable break situations at varying heights during the launch process including at least two separations below 400 feet for a landing straight ahead. Two exercises were also conducted above 400 feet which required a modified circuit to be flown. The considered advantage in these exercises is that the students were assisted in overcoming any reluctance in lowering the nose of the aircraft at realistic cable break heights. The Gliding Federation of Australia (GFA) Instructor's Handbook page 7-21 states that "simulated launch failures should be carried out at various stages of the launch until the pupil has demonstrated failure (competence?) at any stage of the launch". This statement is somewhat vague and perhaps leaves too much to individual instructor preference in what is a critical area of pre-solo training. The recommendation is made that the GFA revise the GFA Instructor's Handbook to define more clearly the type and number of cable failure simulations which should be conducted and the minimum standard that should be attained.

The aircraft departed Rockhampton at 2205 hours for Mackay and was cleared to fly at Flight Level 240. At 2223 hours the pilot called Mackay Tower and reported on descent to 9000 feet. The tower controller instructed the pilot to make a DME (Distance Measuring Equipment) arrival and to report at 10 DME. He advised the pilot that there was a rain shower at the field, moderate rain, and that the visibility was about 6000 metres. At 2227 hours the controller advised the pilot that the weather was improving and the rain showers were mostly to the south-west of the field. He then gave the pilot a choice of left or right circuit and advised that there were a few low patches of cloud. At 2229 hours, the pilot advised that he would be making a left hand circuit for runway 14, (runway 14 is aligned on a magnetic heading of 147 degrees) and the tower controller instructed the pilot to report on final approach. Approximately one and a half minutes later the controller asked the pilot to confirm that the aircraft was making a missed approach. The response from the pilot was "negative". Following this response the controller advised the pilot that the aircraft was very low to the west of the aerodrome and suggested that the aircraft climb. The pilot later reported that he now had the runway in sight and would make another approach. A left circuit was carried out for runway 14 and the aircraft landed without further incident at 2236 hours. Examination of Flight Data Recorder information has shown that at approximately 2231 hours the aircraft was in a landing configuration and aligned with Broadsound Road (part of the Bruce Highway). It subsequently descended to an altitude of 168 feet on the radio altimeter (radio altimeters indicate altitude above ground level). During the latter part of the descent the aircraft was heading 180 degrees magnetic, the same magnetic heading as Broadsound Road, and the computed airspeed reduced to about 137 knots. Witness reports confirm that the aircraft was flown over the highway in a southerly direction, and at very low altitude. An inspection of the area surrounding Mackay Airport and Broadsound Road was carried out in an attempt to ascertain if there were similarities between the runway and the road. Runway 14 is 1981 metres in length and is lit by side variable intensity white lights 65 metres apart. The runway is also equipped with T-vasis approach lights which are used by pilots to determine if the aircraft is above or below the specified three degree glidepath. Broadsound Road is lit by post mounted street lights on either side of the road (approximately 30 metres apart) these run for a distance of about 1200 metres before becoming a single row of lights. The northern end of Broadsound Road is flanked either side by two 24 hour service stations. These provide a intense pool of light either side of the road. There was no similar lighting at the threshold of runway 14. Also, there was no lighting in the area of Broadsound Road that resembles a T-vasis system. It is apparent that the pilot flying the aircraft at the time (the Captain) misidentified Broadsound Road as Mackay runway 14. The flight crew declined to make themselves available to the investigators for interview, apparently under direction from their industrial association. This action by the crew hampered the investigation and resulted in the reasons for the misidentification of the runway not being determined.