Circumstances:

The pilot hired the aircraft for a short flight to practise aerobatics as he intended to participate in a club aerobatic competition later in the day. The fuel quantity was checked by the pilot with a dipstick. There was a total of approximately 120 litres evenly distributed between the left and right wing tanks. The engine run up revealed no abnormalities prior to take off. The aircraft was climbed to 4000 feet in the training area where the pilot practised aerobatics for about five minutes. He then regained the height lost during the aerobatics before the aircraft was deliberately put into a spin. Recovery was effected at about 3000 feet. From 3000 feet the pilot closed the throttle and descended to circuit altitude. He said he cleared the engine on two occasions during the descent by opening the throttle briefly. The aircraft was positioned on a right downwind leg for runway 23 and normal cruise power set.

During the before landing checks the pilot said the engine commenced to run roughly after the fuel boost pump was switched on. The pilot turned onto a base leg where the engine lost all power. As there was insufficient height for the aircraft to glide to the aerodrome the pilot attempted a forced landing in a confined area about 750 metres from the northern boundary. The aircraft struck the ground with a high rate of sink and low forward speed. The pilot suffered back injuries and required assistance to vacate the cockpit. An examination of the aircraft and an engine test run failed to reveal the reason for the loss of power. Witnesses reported the mixture control knob was approximately 25 millimetres out from the full rich position, but it could not be determined if the mixture control was in this position prior to impact.

There is no provision other than internal friction in the mixture control cable to prevent movement of the mixture control. The atmospheric conditions were not conducive to intake icing in a fuel injected engine.

Significant Factors:

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

1. The engine lost power inflight for reasons which were not positively established.
2. The loss of power occurred when the aircraft was outside gliding distance of the aerodrome.
3. The pilot was forced to land in an unsuitable area.

Before DEPARTURE, the pilot removed the fuel filler caps and checked that both tanks were full. He calculated the fuel endurance as 300 minutes. The flight proceeded normally with fuel selection being alternated between the left and right tanks. After a flight time of about 207 minutes, and with the left tank selected, the engine began to surge in a manner described by the pilot as typical of a tank running dry. The pilot immediately selected the right tank and turned the auxiliary fuel pump to "LO". The surging continued so he reselected the left tank and then the right tank, operating the auxiliary fuel pump on "HI" in short bursts. The engine did not restart. By this time, the aircraft had descended to about 2500 feet above ground level so the pilot ceased trouble-shooting and concentrated on landing the aircraft. The aircraft was landed in a cleared area but sustained damage when it nosed into a ditch late in the landing roll. Calculations indicated that 123 litres of fuel had been used from the left tank and 84 litres from the right tank. This was the first occasion since the pilot had been flying the aircraft that he had used more than 90 litres from the left tank. Inspection of the aircraft revealed that the right tank was about one third full. The left tank, however, was dry and five press studs attached to the upper surface of the fuel cell had become detached from the wing upper skin. This allowed the roof of the cell to sag, thus reducing the cell's capacity. The fuel gauge continued to indicate normally. There was, therefore, no way the pilot could have detected the fault other than to run the tank dry. The auxiliary fuel pump is operated by two switches situated side by side on the instrument panel. The right switch is labelled "LO" and is used for engine starting. It will only operate when the ignition switch is turned to start. The left switch, labelled "HI", is used for engine operation should the engine driven pump fail, and also when switching from an empty tank to one containing fuel. Tests determined that the auxiliary fuel pump in the aircraft was operating correctly on both settings. The pilot was under the impression that to leave the auxiliary pump on "HI" would flood the engine. For this reason, he selected "LO" and operated the "HI" switch in short bursts. These actions, along with changing back to the (empty) left tank, were insufficient to purge the air from the fuel lines in the short time the pilot was able to devote to trouble shooting the problem. A placard on the instrument panel lists the procedures to be followed in the event of a major fuel flow fluctuation/power surge. The first item on the list is "AUXILIARY FUEL PUMP ON" but there is no reference to the "HI" or "LO" switches. Had the placard read "AUXILIARY FUEL PUMP - HI", the uncertainty felt by the pilot concerning use of the "HI" setting may not have arisen.

Circumstances:

The aircraft was operating a scheduled service from Brisbane to Port Macquarie with planned intermediate stops at Coolangatta and Coffs Harbour. Weather conditions over the route were influenced by a widespread unstable airmass. The terminal forecast for Coffs Harbour indicated a surface wind of 360/15, visibility in excess of 10 km, 5 octas stratus at 1000 ft, 5 octas cumulus at 2000 ft. Thunderstorms, associated with visibility reduced to 2000 metres were also forecast for periods of up to 30 minutes. The actual weather conditions at Coffs Harbour were generally consistent with the terminal forecast. Runway 03 was in use throughout the evening. Coffs Harbour airport was equipped with NDB, VOR and domestic DME radio navigation aids. A VOR/DME procedure was published for runway 03 approaches. For aircraft not equipped with DME, a VOR or NDB approach was available using common tracking and minimum altitude criteria. Runway 03 was also equipped with a 6 stage T-VASIS and 3 stage runway lighting. All facilities were reported as functioning normally, with the exception of the VOR which was experiencing intermittent power failures due to the effects of heavy rain. The VOR was able to be reset manually from the Coffs Harbour control tower. Although the tower was scheduled to be unmanned before the arrival of VH HOX, the duty air traffic controller elected to man the tower until the aircraft had landed. The controller also called out a technician to attend to the VOR. The aircraft was equipped with dual ILS/VOR and ADF receivers, plus International DME. Domestic DME equipment was not fitted to the aircraft, although required by ANO 20.8. After descending in the VOR/NDB holding pattern, the aircraft was cleared for an instrument approach. The pilot had been told of the intermittent operation of the VOR and had said he would revert to the NDB. At that time, the weather conditions were fluctuating about the circling minima of 950 feet (QNH) and five km visibility. The controller advised the aircraft of a heavy shower to the south of the field. The aircraft subsequently completed the approach and the pilot reported "visual". The controller said he saw the lights of the aircraft in a position consistent with a right downwind leg for a landing on runway 03. The aircraft was then cleared to land. Shortly after, the controller saw the lights of the aircraft disappear briefly, consistent with the aircraft passing through a localised area of rain/cloud. The lights then reappeared briefly, as though the aircraft was turning onto finals, before disappearing. This was immediately followed by short series of "clicks" on the tower frequency. The aircraft was called immediately but failed to respond to any calls. The accident site was located about 1070 metres short of the landing threshold, and about 750 metres to the right of the extended runway centreline. The aircraft was found to have initially struck a nine metre high tree in a nose low attitude, steeply banked to the right, on a track of 050 degrees. After striking the tree with the outboard section of the right wing, the aircraft struck other trees before hitting the ground and overturning. A fire broke out shortly after the aircraft came to rest. As a result of his remaining on duty, the controller was able to provide immediate notification of the accident to the emergency services. This action facilitated the rescue of survivors. A subsequent examination of the aircraft structure, systems and components, found no evidence of any pre-existing defect or malfunction which could have contributed to the accident. The pilot was properly licenced and qualified to conduct the flight. Evidence was provided to show that the pilot had probably flown a total of 930 hours in the previous 365 days, thereby exceeding the ANO 48 limitation of 900 hours. Other breaches of Flight and Duty Limitations were found to have occurred during the previous 12 months, however, during the three months prior to the accident no significant breaches of ANO 48 were found which could have contributed to the accident. Specialist medical advice considered the 30-hour exceedance of the 900-hour limitation was not significant in this accident. Other specialist advice was obtained concerning the possibility of the aircraft being affected by low level windshear or a microburst during the final stage of the night circling approach. It was considered this was not a factor in the accident. Considerable evidence was presented during a subsequent Coroners' Inquest concerning allegations of irregular operating practices by the operator over a period of several years prior to the accident. Much of this evidence was only provided after the granting to witnesses of immunity from prosecution. Despite this, no new evidence was presented which related to the accident flight. The investigation concluded that, on the evidence available, the aircraft was turning onto a short right base leg when it entered a localised area of rain and low cloud. The pilot was required to look out of the right cockpit window to enable him to maintain visual reference with the approach end of the runway. It is considered probable that the pilot briefly diverted his attention from the flight instruments while attempting to maintain that visual reference as the aircraft passed through an area of reduced visibility. During that period, the aircraft continued to roll to the right, resulting in an inadvertent loss of height. The pilot was unable to effect a recovery before the aircraft struck trees.

Significant Factors:

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

1. Low cloud base, with localised rain squalls and reduced visibility.

2. Low level, right hand, night circling approach.

3. Pilot lost visual reference at a critical stage of the approach.

4. Pilot did not initiate missed approach.

5. Pilot probably diverted attention from the flight instruments.

Recommendations:

1. During the course of the investigation it was recommended that the Civil Aviation Authority review its policies and procedures concerning the surveillance of commercial flying operations in general aviation. The objective of the review would be to facilitate the identification and rectification of improper operating practices within the industry. The Authority subsequently advised that the level or frequency of surveillance of commercial aviation operations was being increased.

The pilot reported that soon after takeoff from Cairns the right engine rapidly lost oil pressure accompanied by a rise in the oil temperature. There was also a noticeable drop in manifold pressure and engine rpm. The pilot feathered the propeller and advised the tower of his intention to returned to Cairns where a single engine landing was carried out. A local Licensed Aircraft Maintenance Engineer (LAME) was then engaged to investigate and rectify the defect. After checking the oil quantity and completing a visual inspection of the engine bay the LAME carried out a ground run to verify the extent of the oil pressure loss. All engine parameters including oil pressure and temperature indicated normal during the prolonged ground run. The LAME then advised the pilot that he considered the aircraft to be serviceable and explained to him that the probable cause of the pressure loss was that a piece of carbon had become temperarily lodged under the seat of the oil pressure relief valve. No further "trouble shooting" was carried out by the LAME. Soon after takeoff on the next flight the pilot noticed that the right alternator was not showing a charge. This defect was entered on the maintenance release on arrival in Townsville. The subsequent inspection of the aircraft discovered that the alternator drive "clutch spring" was badly distorted and had caused extensive scoring damage to the internal crankcase casting. The metal filings produced by this scoring action had contaminated the engine oil system. The extent of this contamination necessitated a bulk strip of the engine and accessories. It was found that the crankshaft all main bearings conrod bearings oil pump and oil pump housing had been substantially damaged.

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.