The helicopter was involved in bushfire control when the pilot reported that the engine suddenly lost power at a height of about 150 ft above trees. Attempts to restart the engine were unsuccessful and a forced landing was carried out amongst small trees. Substantial damage was incurred during the forced landing and the pilot sustained minor injuries. The helicopter was subsequently destroyed by the bushfire.

The pilot later reported he had refuelled the helicopter with 300 lbs of fuel about 15 minutes before the accident. Fuel checks at the time indicated that the fuel was not contaminated. The remainder of the fuel, the fuel filter and refuelling equipment at the base, were subsequently checked after the accident and were reported to be clean. As the engine was extensively damaged by the bushfire, the reason for the failure was not determined.

The right main landing gear collapsed as the aircraft touched down on the grass strip at Lake Keepit, after retrieving a glider from a paddock.

Inspection revealed that one of the landing gear attachment bolts had failed. Further investigation revealed that the failed bolt was not of the correct type. It was not determined when or why an incorrect bolt had been fitted.

The crew of a Saab 340 aircraft reported downwind at Ballina NSW for runway 24, in marginal VMC with passing showers. A Mitsubishi MU2 aircraft was also operating within the MBZ and the two aircraft had established two-way communications.

The Saab crew reported that they were established on final approach for runway 24 when the MU2 turned for a tight base leg in front of them. The crew of the Saab broadcast their position on short final for runway 24. Although they state the pilot of the MU2 did not respond to this call, he flew through the centre line of the runway and continued north with his landing gear extended.

The pilot of the MU-2 stated to the owner of the aircraft, that he had broadcast his position joining downwind. As he received no reply to this call, he assumed that the Saab had already landed and continued the approach. He also made a broadcast turning base, and received a reply from the Saab that they were established on final. Due to other traffic in the area he completed a holding pattern before attempting another approach.

The crew of an international Boeing 747 departing runway 16 had been cleared for a KEPPA 1 Standard Instrument Departure. Departure instructions had been issued by Departures North for the aircraft to initially maintain 3,000 ft due to overflying traffic. The B747 was rolling when the tower controller called Departures North to obtain departure instructions for a Boeing 767, that had been cleared for a DOSEL 6 Standard Instrument Departure from runway 27. The Departures North controller indicated he would call back shortly with departure instructions in respect of the B767.

The departures controller observed the B747 airborne and cleared the aircraft to continue its climb, having established that separation existed with the overflying traffic. At this stage the departures controller called the tower controller and issued departure instructions for the B767 to maintain 3,000 ft. This would allow the B767 to pass under the path of the departing B747.

The departures controller subsequently observed the B767 to be airborne, with the B747 still south-west of the aerodrome, in a left turn climbing slowly through 2,800 ft. As the controller considered the B747's rate of climb insufficient to preserve vertical separation between the two aircraft, the departures controller turned the B747 onto a westerly heading and passed traffic information to the crew in respect of the B767.

Horizontal separation between the two aircraft reduced below the 3 NM standard before vertical separation standards were established. The two aircraft were further processed without incident.

The pilot of a Rockwell Commander 114 aircraft had completed a short local flight and was operating in the circuit pattern at Maitland.

The pilot reported having difficulty sighting some slower traffic ahead. The aircraft subsequently landed with its landing gear retracted, sliding for approximately 130 metres. The pilot and passenger were able to exit the aircraft without assistance. After establishing that it was safe to re-enter the aircraft the pilot & passenger checked that the power and fuel were switched off. At this stage they noted the gear selector was in the down position.

Post accident activation of the landing gear alternate extension system successfully lowered the gear. No defect was found with the operating system that would have prevented the landing gear from operating normally. Damage to the underside of the aircraft was consistent with the landing gear being retracted at the time of impact.

The pilot reported that she inadvertently selected the landing gear up, instead of the flap, during the landing roll. Aircraft speed was about 70 kt when the mainwheels began to retract. The landing gear warning horn sounded as the gear retracted. The right wing settled onto the ground and the aircraft slewed to a stop. Both propellers suffered ground strikes. The pilot indicated that she was not distracted by anything in particular during the selection process.

The pilot reported that during the turn around at Brewarrina, he had not stopped the engines and the freight was placed in the aircraft through the rear cabin door. The cockpit door was not opened during the turn around. The pilot said he carried out the pre-takeoff checks and backtracked on runway 21 to use the full length of the runway for takeoff. After becoming airborne and establishing a positive climb rate he selected the gear up. Seconds later the pilot heard an explosion-like sound and noticed the cockpit door had opened. The pilot said his initial reaction was to grab the door and attempt to close it, but due to the aircraft being in a critical stage of flight he concentrated on flying the aircraft. Judging that he had sufficient runway ahead of him to land the aircraft he closed the throttles. The pilot said that after losing considerable height he realised the gear was not down, so he immediately applied full power. The pilot flew the aircraft away from the runway surface and carried out a 500 ft circuit. He subsequently carried out a normal landing, and taxied clear of the runway.

An inspection of the aircraft revealed that both propellers had contacted the runway, the step behind the right-wing root had been bent up, and the ADF sensor antenna had also been bent. The pilot said that he was certain that the cockpit door had been positively locked before the previous departure from Bourke, and that the locking handle had not been moved since that time.

The aircraft was being used to muster cattle at Tallering Station. The pilot reported that the aircraft's fuel tanks had been filled the night before the accident. On the morning of the accident, the pilot again checked that the fuel tanks were full.

Having been airborne for approximately 4.75 hours, the pilot flew the aircraft towards the station homestead to refuel. The pilot estimated that there was sufficient fuel to remain airborne for at least a further 45 minutes. However, almost immediately, the aircraft's engine began surging and misfiring. The pilot reported that he completed the appropriate checks and when he pumped the throttle, the engine gave some response for approximately 5 to 10 seconds before it finally stopped.

The pilot reported that he attempted to find a suitable forced landing area but the aircraft impacted trees at approximately 40 kts late on final approach. The pilot was uninjured. Later, approximately 22 L of fuel was drained from the aircraft's left fuel tank but none was found in the right tank.

The aircraft's left and right fuel tanks were vented through a vent line connected to the left fuel tank. The vent line is fitted with a vent valve. However, the right fuel tank also had a vented cap. The subsequent engineering inspection found that the vent line valve had deteriorated and was sticking closed. It is likely that the vent valve had stuck closed at some point during the flight. The right tank probably fed quicker than the left tank due to it venting correctly through the vented cap. When the right tank contents had been exhausted, the low air pressure in the left tank probably created an insufficient head of fuel to feed the engine.

A defect report has been submitted to CASA by the operator's engineering organisation, recommending that both fuel tanks be fitted with vented fuel caps.

Report not released due to no IP comment from the Indonesian agency on this joint investigation report. ASOR hard copy held on occurrence file. Report not to be released without the approval of the Director or a DD Signed Alan L Stray Deputy Director Investigations 6 July 1998

A Cessna Conquest, VH-LBY was flying at FL240 from Plutonic to Perth via the Meekatharra and Mount Magnet radio navigation aids. A BAE 146, VH-NJZ was flying at FL250 from Perth to Paraburdoo via the Rusty reporting point and the Meekatharra aid. A second Conquest, VH-NFD was tracking to Mount Magnet, also via Rusty and the Meekatharra aid at FL250. At 0931, the pilot of LBY requested a climb to FL260 but the sector air traffic controller advised that the level was unavailable due to opposite direction traffic, (a second BAe 146, VH-NJN). VH-NJN was behind NJZ at the non-standard level of FL260. The Sector controller then cleared NJN to climb to the standard FL270. At 0935, the controller cleared LBY to climb to FL260 with a requirement for the aircraft to achieve the level by 0940. Approximately 1 minute later, the controller apparently recognised that a breakdown in separation may be possible between LBY and NJZ. He requested a level check from the pilot of LBY that indicated that the aircraft were vertically separated by 300 ft. He did not issue traffic information to either aircraft. Soon after, the pilot of NJZ requested the position of LBY and the aircraft were 17 NM apart and closing. The controller then instructed LBY to expedite the climb. Three seconds later, the pilot of LBY reported maintaining FL260.

The pilot of NJZ subsequently reported that he had calculated a time of passing with LBY of 0940 and when he heard LBY was cleared to climb, he began an immediate visual scan of the area ahead and turned the aircraft's landing lights on. The pilot of NJZ reported that approximately 1 minute after the pilot of LBY reported maintaining FL260, he sighted LBY. The pilot of LBY reported that approximately 2 minutes after establishing FL260, he sighted NJZ passing below. A breakdown of separation had occurred because the required 10 minutes separation, based on the time the aircraft expected to pass each other, had not been achieved. The aircraft had not been issued with the required traffic information when the controller became aware that the aircraft were in unsafe proximity to each other.

Whilst the controller had 3 sectors combined at the time of the incident, the workload was reported as being light to moderate and not considered excessive. Personnel were available to provide assistance if requested and evidence indicated that the controller was not under pressure at the time of the incident. The controller had not calculated a time of passing between LBY and NJZ because the aircraft were to be separated by 1,000 ft and were not in conflict. The controller's requirement for LBY to reach FL260 by 0940 was 10 minutes before the calculated time of LBY passing NFD, therefore, it is likely that the calculated separation requirement was based on LBY's passing of NFD, not NJZ.

The controller appears to have been preoccupied with ensuring separation between LBY and NFD. Therefore, he overlooked separation requirements with NJZ. This oversight subsequently led to a breakdown in separation between NJZ and LBY.