The aircraft departed Bankstown on a flight to Waikerie at a cruising altitude of 8,000 ft. About 90 mins after take-off the pilot selected the left and right auxiliary tanks to supply fuel to their respective engines. Some 68 mins later, when the auxiliary fuel tank contents had both reduced to about 20-25 lbs, the pilot turned the left engine fuel selector to the left main tank. One minute later, he turned the right engine fuel selector to the right main tank. Approximately two minutes later the pilot noticed a change in the tone of the left engine and felt a slight shudder through the airframe. The left engine began to run rough, which worsened until it lost all power and stopped, despite attempts by the pilot to restore engine power through the use of the auxiliary fuel pump and changes in mixture. Attempts to restart the left engine were also unsuccessful.

The pilot transmitted a PAN report and commenced the left engine shutdown checks. However, the right engine commenced to run rough before it also suffered a complete loss of power, which could not be restored. The pilot transmitted a Mayday report and carried out a forced landing onto a field in the Malee National Park, approximately 25 NM east of Mildura. During the landing the aircraft suffered substantial damage, including a small fire in the right main tank, which the pilot was able to extinguish using a portable extinguisher. He then activated an emergency locator transmitter (ELT). By 1640 search aircraft had located the accident site with the assistance of ELT signals.

Local police services attended the scene. The pilot subsequently discovered a substantial amount of white powder, later identified as sugar, in the auxiliary fuel tanks. As it appeared there had been some form of deliberate contamination of the fuel system, the police assumed responsibility for any further investigation.

The Boeing 727 VH-ANA was operating on a scheduled flight from Brisbane to Cairns. The aircraft was third in the arrival sequence and had been positioned on left downwind for runway 15 by the Approach One (APP1) controller. The other two aircraft, a Britten Norman Islander VH-INO, and a Boeing 737 VH-TJU, had been sighted by the crew of ANA who were then instructed to make a visual approach and to follow TJU. The co-pilots of ANA and TJU were the pilots flying, and the pilots-in-command were carrying out the non-flying pilot support duties in each aircraft.

The crew of ANA, having been instructed to sight and follow TJU, extended downwind for about 2 NM to ensure adequate separation from TJU. As ANA was turning onto the base leg of the circuit, the Aerodrome controller (ADC) instructed the crew of ANA to continue the approach.

Meanwhile, the pilot of a Cessna 182, VH-DAL, who had been conducting parachuting operations 3 NM west of the aerodrome, was returning for a landing. DAL was being controlled by the Approach Two (APP2) controller. The APP2 controller noted the position of the other arriving aircraft on the radar display. He judged that there would be sufficient time to land DAL between TJU and ANA if the pilot was assigned runway 12, the non-duty runway.

The ADC was the arbiter for the use of the non-duty runway for 'one-off' landings and the APP2 controller co-ordinated the use of runway 12 with the ADC. The ADC concurred with DAL being processed for landing on runway 12, between the landings of TJU and ANA on runway 15.

As TJU was landing, the ADC requested the pilot of that aircraft to hold short of the Bravo 4 taxiway or roll through to Bravo 5 taxiway and to advise his preference. This was to allow an aircraft stopped on Bravo 4 to cross runway 15. The crew of TJU were unable to acknowledge the request immediately, as the aircraft was still decelerating with reverse thrust, and their priority was to complete the landing roll safely. The pilot in command of TJU had not completely understood the instruction and told the co-pilot to disregard it until they had slowed to a safe speed. The aircraft was stopped short of Bravo 4 taxiway, and the crew then advised the ADC that they would hold in their present position. The ADC's intention was to taxi an aircraft across the runway in front of TJU. The ADC advised the crew that he would 'get the jet away' in front of them and, that once it had passed, they were clear to taxi via Bravo 4.

The pilot of DAL had been instructed by the APP2 controller to make a straight-in visual approach for runway 12. The APP2 controller then confirmed with the APP1 controller that he was aware that DAL was being sequenced for runway 12. The APP1 controller acknowledged the advice of the use of runway 12 for DAL. The APP2 controller observed on the radar display that separation between DAL and ANA was reducing. He then contacted the ADC and offered to take DAL out of the arrival sequence and to re-establish the aircraft behind ANA. The ADC declined the offer and stated that if there was insufficient separation with ANA he would instruct the pilot of DAL to go around. The APP2 controller then instructed the pilot of DAL to contact the ADC. The pilot of DAL acknowledged and changed to the aerodrome control frequency.

When the pilot of DAL contacted the ADC and reported on final he did not state which runway he was making the approach for, nor was he required to do so. Also, the ADC did not provide traffic information to either the pilot of DAL or the crew of ANA about the other aircraft, or that both runway 15 and 12 were in use. The ADC instructed the pilot of DAL to continue approach and to expect a go around due to traffic on runway 15. The ADC then requested the crew of TJU to expedite vacating runway 15. ANA was now established on final approach and the ADC instructed the crew to continue approach and to expect a late landing clearance. The crew of ANA were watching TJU closely and the pilot in command assessed that he would have to go around if TJU remained on the runway for much longer. The crew of ANA then reviewed the missed approach procedure. After ANA had passed through 300 ft, the pilot in command decided to go around and was about to instruct the co-pilot to do so when the ADC cleared ANA to land.

As the co-pilot began the landing flare, the crew were surprised to see DAL passing from right to left in front of them. DAL crossed the runway in front of ANA and was cleared to land when at or near the threshold of runway 12. The crew of ANA were of the opinion that a mid-air collision may have occurred had the go-around been executed.

The incident was a result of inadequate management of the arrival sequence, and inappropriate decisions made by the aerodrome controller.

The investigation revealed that there was a need to evaluate the application of separation standards for all controlled aerodromes with intersecting approach and departure paths and runways. In response to the BASI recommendation R970067, Airservices Australia and the Civil Aviation Safety Authority conducted a review of the applicable standards and procedures.

Shortly after take-off from runway 17, at about 200 to 300 feet above the ground, the left engine lost power. The pilot shut the engine down and feathered the propeller and returned for a safe landing on runway 28.

An engineering inspection revealed that the head had completely separated from number three cylinder of the left engine. The separation occurred in such a way that the induction pipe separated from its flange which resulted in there being no power available from the other cylinders. The cylinder that failed was only 200 hours old since new. The engine had been fitted with six new cylinders, all from the same batch from the same manufacturer.

Because of this the operator decided to check the five remaining cylinders. Initial compression checks revealed no abnormalities. However, a wet compression check revealed that all five cylinder heads were porous due to faulty manufacture.

Details of the operator's findings were passed to CASA and as a result an airworthiness directive (CAO Part 106 AD/LYC/101) was issued requiring some other cylinders from the same manufacturer to be inspected within specified time frames.

The pilot reported that while conducting an aerial inspection of cattle, he flew the helicopter through a descending right turn into wind. As he commenced to flare the helicopter at about 100 ft AGL, the engine RPM dropped rapidly. He lowered the collective control and wound on more throttle. There was no response from the engine.

The helicopter rapidly developed a high sink rate which the pilot was not able to arrest completely before impact with the ground. The helicopter bounced twice and rolled onto its left side. Neither of the two occupants were injured. They escaped from the wreckage through the right cabin exit.

The licenced aircraft maintenance engineer who recovered the helicopter from the accident site reported that he could not find a mechanical reason for the power loss. He said that the helicopter was being operated on mogas which is a more volatile fuel than avgas and in the higher temperatures, it tends to vaporize in the fuel line, causing an interruption of fuel to the engine.

The helicopter was fitted with an approved emergency locator transmitter which operated, alerting the Search and Rescue Centre in Brisbane.

The aircraft planned to track from Karratha to Perth via Morawa. This track used the Karratha navigation aids and the Morawa non directional beacon (NDB) as the only aids for more that 500 NM. The Morawa NDB has a rated coverage of 50 NM. As the aircraft was not fitted with area navigation systems, it relied solely on off-set fixes from navigation aids not on track to supplement the information from the two on-track aids. The aircraft had previously experienced tracking difficulties on the route, and these were exacerbated by the known interference between the Morawa NDB and Laverton NDB. The Laverton NDB has the same frequency as the Morawa NDB. A computational error by the crew, associated with an unexpected wind shift, combined with the deficient tracking aids to cause the aircraft to deviate from the required track.

Since the incident, the operating company has directed that any of its aircraft without area navigation systems are to track on routes that pass over navigation aids which provide accurate enroute tracking information.

FACTUAL INFORMATION

A Royal Australian Air Force (RAAF) F111 had been flight planned to conduct a flight from Amberley to Evans

Head weapons range (designated Restricted Area 620 [R620]) and returning via overhead Coolangatta at flight level (FL) 160. R620 was activated for the flight and the highest useable level for aircraft on the range was 7,000 ft. The flight plan indicated that the intention was for the F111 to operate in R620 for 20 minutes below 7,000 ft. The aircraft departed Amberley and entered R620. A Metroliner had been flight planned to operate a flight from Ballina to Coffs Harbour at FL120. The pilot of the Metroliner notified the Brisbane Sector 2R controller when the aircraft taxied at Ballina for departure. Sector 2R provided a radar advisory service (RAS) and a search and rescue alerting service for aircraft operating outside controlled airspace below 7,500 ft to the south of Coolangatta. The airspace above 7,500 ft is controlled airspace which is the responsibility of Sector 2G. The Sector 2R position was under the control of a trainee being supervised by a rated controller.

The crew of the Metroliner notified the Sector 2R controller when the aircraft taxied for departure at Ballina. The Sector 2R controller advised the Sector 2G controller that the Metroliner was taxiing at Ballina. The Sector 2R controller issued a secondary surveillance radar (SSR) squawk code to the crew of the Metroliner and also advised that a clearance, on climb, through R620 was not available. The crew advised that they would climb to 8,000 ft overhead Ballina and then track to Coffs Harbour. The Sector 2R controller issued traffic information on the F111, which was expected to depart R620 approximately 10 minutes later, and instructed the crew to remain outside controlled airspace and to standby for a clearance.

The Sector 2R controller advised the 2G controller of the Metroliner's departure time from Ballina and the crew's intentions. The Sector 2G controller advised that he had no restrictions for the Metroliner to climb to 8,000 ft and to track to Coffs Harbour as requested. The Sector 2G controller was busy with other aircraft in the northern part of his sector which were diverting around weather. The supervising controller on Sector 2R coordinated with the Sector 2G controller for the Metroliner to remain on the Sector 2R frequency as that aircraft would leave controlled airspace approximately 12 NM south of Ballina. The Sector 2R controller issued a clearance to the crew of the Metroliner to climb to 8,000 ft overhead Ballina and then to track to Coffs Harbour. The crew readback the clearance.

The Sector 2R controller identified the Metroliner overhead Ballina and verified the SSR altitude label on the radar display. She instructed the crew of the Metroliner that on reaching 8,000 ft they could track direct to Coffs Harbour. This was acknowledged by the crew.

The crew of the F111 contacted the Sector 2G controller for a clearance to climb to FL160 on track to Ballina as the aircraft departed R620. The departure from R620 was approximately 10 minutes earlier than expected based on flight planned time intervals and the aircraft's departure time from Amberley. The Aeronautical Information Publication (AIP) requires flight crews to notify air traffic services as soon as possible when the route segment time interval or estimate at the next reporting point varies by more than two minutes. The Sector 2G controller did not observe a radar return and issued a SSR code to the crew and instructed them to operate the aircraft's special position identification (SPI) function. The SPI function was used to enable the controller to radar identify the aircraft on the radar display. The controller did not instruct the crew that a clearance was not available or to remain outside controlled airspace, in accordance with air traffic control procedures.

The crews of F111 aircraft departing R620 normally contacted Sector 2G in preference to Sector 2R due to better communications with the former. Also, F111s departing R620 are only in Sector 2R's area of responsibility for a short period before entering Sector 2G. When the crew of the F111 did not have a clearance as the aircraft passed 7,000 ft the crew halted the aircraft's climb and maintained 8,000 ft. At that level, the F111 was within controlled airspace. The crew was unsure of the status of the airspace above R620 and commenced a slow descent. The Sector 2G controller conducted coordination with a number of other air traffic control positions and communicated with a number of aircraft before returning his attention to the F111.

The Sector 2R controller observed the F111 departing R620 on a heading that would conflict with the Metroliner. The controller advised the crew of the Metroliner that the F111 was 10 NM away and heading in the opposite direction. Due to the high rate of closure between the two aircraft the Sector 2R supervising controller instructed the crew of the Metroliner to turn right immediately and also advised that the F111 was maintaining 8,000 ft and was not on the sector frequency. Analysis of the radar data indicated that just prior to the Metroliner turning right, the two aircraft were 7.5 NM apart, on reciprocal headings, with a vertical separation of 100 ft and a groundspeed rate of closure of 750 kts.

The Sector 2R supervising controller advised the Sector 2G controller to issue traffic information to the F111 crew on the Metroliner. The Sector 2G controller transmitted the information and instructed the crew to turn right to avoid the Metroliner. This was acknowledged by the F111 crew. The Sector 2G controller did not observe the radar symbol for the F111 until it was pointed out to him by the Sector 2R supervising controller. The Sector 2R and Sector 2G radar displays receive radar data from different radar sensors and generally Sector 2R displayed aircraft at lower levels over R620 than Sector 2G.

The Sector 2R supervising controller updated the traffic information to the crew of the Metroliner when the aircraft were approximately 4 NM apart and the two aircraft passed shortly after. The radar data showed that the horizontal separation was 4.4 NM, and the vertical separation was 600 ft. The required separation was 5 NM horizontally or 1,000 ft vertically. The Sector 2G controller identified the F111 and issued a clearance for the aircraft to enter controlled airspace on a heading of 360 degrees on climb to FL160. There was a breakdown in separation.

ANALYSIS

The Sector 2G controller normally instructed crews of aircraft requesting clearances to enter controlled airspace that a clearance was not available and to remain outside controlled airspace. However, due to the problems with aircraft diversions as a result of weather, he did not use the standard phrase to the crew of the F111. He may have thought that this would save some time or may have forgotten to use it because of his workload.

The reason for the crew of the F111 departing R620 earlier than planned could not be ascertained. The crew should have remained within the confines of R620 or outside controlled airspace until a clearance was issued by ATC. If they had remained outside controlled airspace the crew would have had to change frequency to the Sector 2R RAS frequency. A change to the RAS frequency would have provided an opportunity for the crew of the F111 to receive traffic information on aircraft outside controlled airspace.

Advice from the crew of the F111 to ATS of the amended departure time from R620 would have provided an increased level of safety. Notification of the earlier departure time would have assisted the sector controllers to plan the safe and expeditious entry of the F111 into controlled airspace.

The Sector 2R controllers were aware that the F111 may conflict with the departing Metroliner and consequently passed traffic information to the crew of the Metroliner at the earliest opportunity. The controllers were able to provide avoidance instructions to the crew of the Metroliner when it appeared that they may conflict with the F111.

SIGNIFICANT FACTORS

1. The crew of the F111 departed R620 approximately ten minutes earlier than that indicated by the flight plan.
2. The crew of the F111 did not advise ATS of the revised flight estimates.
3. The Sector 2G controller did not instruct the crew of the F111 that a clearance was not available and to remain outside controlled airspace.
4. The crew of the F111 entered controlled airspace without a clearance.
5. The Sector 2R supervising controller provided directions to the crew of the Metroliner to avoid the F111.

The pilot was tasked with spraying crop with fungicide in a paddock situated in an undulating timbered area. The wind was from the east at 10 - 15 kt, and the pilot elected to commence the first spray run in a downwind direction. This required a steep descent from over the treetops to pass beneath a swer power line located across his flight path.

The pilot reported that he encountered severe turbulence and windshear in the lee of the trees, and was unable to prevent the aircraft, which had a full hopper, from descending into the top of a tree. This caused an immediate deterioration in airspeed, damage to the wing leading edges and removal of the spray pump. The aircraft flew out of the tree in a semi-stalled condition, and being unable to maintain height to fly over the swer power line the pilot dived the aircraft to pass beneath it.

The aircraft wheels became entangled in the crop, slowing the aircraft further, and caused it to impact the ground heavily. The impact damaged the landing gear and removed the hopper door allowing the fungicide load to dump.

Due to the impact force, and the load being dumped, the aircraft became airborne again and was yawed to the right by the crop dragging on the landing gear. It then collided with a fence which turned it through 180 degrees as it came to a stop.

The aircraft was on approach for landing with a 10 - 15 kt crosswind from the left. The pilot stated that he was holding the left wing down to counteract the crosswind, but as he commenced to flare prior to touchdown a stronger gust of wind moved the aircraft to the right.

The aircraft touched down at the side of the airstrip on its left main wheel, possibly in soft sand, while still moving sideways. This imposed a side load to the landing gear leg which sheared the attachment bolts allowing the leg to separate from the wing.

It was reported that the aircraft was being used to spread powered fertiliser. There had been light rain prior to the accident flight and the wing surfaces were wet. During loading the wind momentarily lifted the sock, used to fill the hopper, clear of the aircraft and some powder was blown onto the upper surface of the right wing. The rain was not heavy enough to wash the powder off. The aircraft's weight was reported to be at its maximum for take-off. The average wind was a westerly at 8 kts with significant shifts reported as occasional squalls passed through.

The pilot commenced a take-off, with 10 degrees of flap set, towards the west and into wind. The strip slopped down and then up. As the aircraft accelerated the pilot flew the tail off the ground. Shortly afterwards the left wing also lifted, pivoting the aircraft over the right wheel. The pilot introduced left aileron to keep the wings level until he reached take-off speed. The aileron control reached the left stop at the same time as the aircraft became airborne. It continued to roll to the right and began to yaw right. The pilot introduced rudder and then brake in an attempt to stop the roll and yaw. The rudder made little difference, and the brakes were completely ineffective as the wheels were off the ground.

The pilot closed the throttle and, as the aircraft settled back onto the ground in a left-wing-high attitude, it collided with a fence. The aircraft ripped 76 m of fence from the ground before it cartwheeled and overturned.

The aircraft's flight manual contains a caution which indicates that aileron effectiveness is reduced when flaps are used for take-off. The pilot reported that he used flaps as the aircraft was at maximum weight and the strip length was restricted. The aerofoil section of the wings on the AT502 is designed for maximum efficiency. The aircraft manual indicates that any ice must be removed from the wing prior to take-off because of its effect on wing-produced lift. It is probable that the powder-contamination on the right-wing surface adversely affected its aerodynamic characteristics resulting in the roll experienced by the pilot. The pilot's ability to control the roll with aileron was reduced by his use of flap for take-off. The result was a roll and yaw which the pilot was unable to correct before the aircraft collided with the fence. It is possible that a squall-induced wind shift also contributed to the loss of control.

The pilot reported that the radio microphone failed as he approached Sandstone. Then the landing gear motor stopped working and the gear only extended about halfway when he lowered it on downwind. There was no response from the gear when the selector was subsequently moved to either the up or the down position. The pilot attempted to extend the gear using the alternate system however, the system pressure fell to zero after two or three cycles of the hand pump. He operated the pump for several more minutes without any appreciable result. At no stage did the gear lights indicate the gear was down.

As the radio was inoperative, the pilot decided to land at Sandstone rather then return to Kalgoorlie. He observed that, although the main landing gear was down, it was not as far forward as it usually was when locked. On touchdown, the main wheels were dragged backwards and the aircraft slid to a stop on its lower fuselage.

No gear faults were identified during the post-accident inspection or at the time of the repair. The system has worked normally since the accident.