The pilot of a Saab Aircraft AB SF-340B (Saab), on final to runway 16R at Sydney airport, was instructed by the aerodrome controller (ADC) to turn right heading 240 degrees M due to an unidentified aircraft in the control zone. The unidentified aircraft was observed to turn north and pass the Saab with 2 NM lateral and 400 ft vertical displacement. The required separation standard was either 3 NM laterally or 1,000 ft vertically. The unknown aircraft was subsequently identified as a Piper Aircraft Corporation PA-23-250 (Aztec). The Aztec pilot had entered the Sydney control zone without a clearance, resulting in an infringement of separation standards.

The Aztec pilot had intended to conduct a visual flight rules (VFR) flight from Bankstown, located 9.5 NM west of Sydney, to Grafton. He had recently purchased the Aztec and this was the first significant trip in that aircraft. The pilot had previously flown a Beech Baron and had completed a flight check on the Aztec.

Flights under the VFR conducted below 10,000 ft required a pilot to operate in the following meteorological conditions:

• flight visibility greater than 5,000 m;
• clear of cloud when in a general aviation control zone; and
• 1,500 m horizontally and 1,000 ft vertically from cloud while en route.

The Bankstown terminal area forecast, issued at 0433, covering the period from 0600 to 1900 Eastern Summer Time forecast a flight visibility of 5,000 m in smoke and a few (1 to 2 OKTAS) clouds at 3,000 ft. The forecast indicated that visibility was expected to increase to greater than 10 km by mid afternoon. The actual meteorological conditions reported at Bankstown during the morning of the occurrence were:

• 0900: westerly wind at 9 kts with visibility of 8,000 m, no cloud below 12,500 ft and temperature of 18 degrees C;
• 0900 report was amended at 0919: westerly wind at 9 kts with visibility of 3,000 m in smoke, no cloud below 12,500 ft with the sky obscured and temperature of 18 degrees C;
• 0930: south-westerly wind at 6 kts with visibility of 6,000 m, no cloud below 12,500 ft and temperature of 18 degrees C;
• 1000: wind was calm with visibility of 7,000 m no cloud below 12,500 ft and temperature of 19 degrees C; and
• 1030: north-westerly wind of 4 kts with visibility of 7,000 m, no cloud below 12,500 ft and temperature of 20 degrees C.

The actual reported weather conditions at Sydney during the morning were:

• 0900: southerly wind at 7 kts with visibility of 4,000 m in smoke and scattered (3 to 4 OKTAS) clouds at 1,600 ft and temperature of 18 degrees C;
• 0920: southerly wind at 7 kts with visibility of 6,000 m in smoke with a few (1 to 2 OKTAS) clouds at 4,500 ft and temperature of 18 degrees C;
• 0930: southerly wind at 7 kts with visibility of 6,000 m in smoke with a few (1 to 2 OKTAS) clouds at 4,500 ft and temperature of 18 degrees C; and
• 0955: south-easterly wind at 7 kts with visibility of 7,000 m in smoke with a few (1 to 2 OKTAS) clouds at 4,500 ft and temperature of 19 degrees C.

Weather conditions at the time were visual meteorological conditions that had been affected by bushfires in the Sydney basin.

The pilot had delayed departing from Bankstown in anticipation of the weather conditions improving and subsequently departed at about 0945. Immediately after take-off, while the pilot was still monitoring the Bankstown ADC frequency, the right engine commenced to `run rough'. The pilot reduced power on that engine and attempted to identify the cause of the problem. The pilot decided to return to Bankstown as the situation could not be rectified and the aircraft was vibrating. As he manoeuvred to return, the flight visibility was such that the pilot could not see Bankstown airport. He was aware of the aircraft's proximity to the Sydney control zone and reported that he was about to call Sydney air traffic control for a clearance when he was advised by the departure south controller that the Aztec had infringed the control zone.

The Aztec pilot had selected code 1200, the nominated code for a VFR flight operating in non-controlled airspace (and not participating in a radar information service) and was operating the aircraft's transponder.

The Sydney Aerodrome and Director West controllers saw, on the air traffic control radar, that the Aztec was in the control zone, northwest of Canterbury racecourse, and likely to conflict with aircraft on final to runway 16R. The ADC instructed the pilot of the Saab to turn right to avoid the Aztec. The pilot of another aircraft was similarly instructed.

Before the pilot could return to Bankstown, the right engine on the Aztec started to operate normally. The pilot decided to continue the flight and tracked to the north to vacate the control zone and to join the VFR lane. The flight continued uneventfully to Coffs Harbour where the pilot refuelled the aircraft. Subsequently, after take-off from Coffs Harbour, at approximately 300 ft, the right engine surged and the pilot landed the aircraft on the remaining runway. The pilot taxied the aircraft to a hangar for maintenance action and on reaching the hangar the left engine stopped. Inspection by a licensed aircraft maintenance engineer (LAME) found that the cooling flaps on both engines were inoperative and had caused the engines to overheat. The LAME re-rigged the cowl flaps for maximum cooling and a subsequent engine ground run confirmed normal operation.

A Boeing 767-338ER (B767) was maintaining flight level (FL) 370 and had been assigned FL330 to maintain separation with a Cessna Citation 500 (C500), maintaining FL310, that was crossing the track of the B767. The controller entered FL330 into The Australian Advanced Air Traffic System (TAAATS). He subsequently, and unintentionally, assigned the crew of the B767 descent to FL300. The controller received a cleared level adherence monitor alarm (CLAM) when the B767 descended through FL326. Vertical separation between the B767 and the C500 reduced to 700 ft, and horizontal separation reduced to 3.4 NM. The required separation standard was 2,000 ft or 5 NM. There was an infringement of separation standards.

The controller had initially cleared the crew of the B767 to descend from FL370 to FL330. The descent was to be commenced at the discretion of the crew. He then entered FL330 into TAAATS as the new cleared flight level (CFL). The controller reported that he had made the necessary TAAATS entries on receipt of the correct level read back from the crew of the B767. There were no subsequent TAAATS entries required in relation to FL330 being assigned to the crew of the B767.

The B767 crew reported leaving FL370 approximately five minutes after they had been assigned FL330. The controller reported that he had intended to confirm FL330 as the cleared flight level with the B767 crew at that time, but he unintentionally assigned FL300. The crew of the B767 read-back FL300 and continued descent through FL330. The controller did not detect from the read back that he had assigned an incorrect flight level. There were no subsequent opportunities for the controller to realise the error until the CLAM alarm from TAAATS.

The controller indicated that he considered his workload at the time of the occurrence to be light. He was responsible for two sectors of airspace but he did not believe that the increase in workload caused by the combination of the two sectors contributed to the error. The replay of the voice recording indicated that the controller had up to ten aircraft under his control at the time of the occurrence. Three of those aircraft had requested a shorter route. The controller accommodated the requests because some of those aircraft were involved in bush fire fighting operations. When the routes for those aircraft were amended, the associated flight data record in TAAATS also needed to be amended and the changes needed to be coordinated with adjacent sectors. The controller did not believe the extra workload generated by those tasks contributed to the occurrence.

The controller was also the team leader on the shift. He reported that there were no distracting team leader issues at the time of the occurrence. The controller did not believe he was fatigued.

There were five persons on board the Cessna 185 floatplane when the pilot taxied for a charter flight from the wharf at Strahan, Tas. The pilot steered the aircraft out of the cove into more open water to position the aircraft for take-off into the prevailing northerly wind.

The pilot reported that the aircraft had travelled approximately 1 km, and was at the start of the planned take-off run, when he assessed the water state as being marginal for the aircraft. He then began steering the floatplane back towards the wharf when a catamaran cruise boat, travelling in the opposite direction, passed on the left. Waves generated by the accelerating catamaran prompted the pilot to steer the floatplane left to cross the bow-wave head on. After negotiating the wake, the pilot resumed course to the wharf. The pilot then became concerned about the buoyancy of the right float and broadcast his concerns. He increased power and applied left aileron and aft elevator to counter the increasing list to the right but the aircraft nosed over and came to rest inverted.

The pilot and two passengers were able to evacuate quickly from the submerged cabin and were followed a short time later by another passenger. At that time, the pilot was diving to assist the remaining passenger, who eventually surfaced unaided. Three life jackets floating in the water nearby were retrieved by the pilot and were donned by passengers. The pilot and passengers were rescued a short time later by a nearby boat and another floatplane.

The pilot had been tasked to use a floatplane that was positioned in a hangar near the water. While the preflight inspection in the hangar had revealed only a small amount of water in the two float lockers, the pilot intended to pump out the other six float compartments on each float when the floatplane was tied up at the wharf. He was aware that the floats had been prone to taking on water and that pumping out the floats prior to his previous flights in the aircraft had removed substantial amounts of water. It was also standard operating procedure for the operator's pilots to pump out the float compartments as part of their daily preflight inspection. However, the floats were not pumped out, and the aircraft departed the wharf with an unknown amount of water in the floats.

While the pilot could recall being subject to time pressure after the aircraft was positioned at the wharf, he was not able to clearly remember the specific circumstances that contributed to the situation. The pilot reported that he had arrived at work at 0815 Eastern Standard Summer Time and started his duty period at 0830 for a planned 0900 departure.

The pilot stated that, soon after departure from the wharf, the aircraft `felt odd'. He then radioed a colleague located in the wharf office, who indicated that the right wing was slightly low. At the time the pilot attributed the aircraft attitude to fuel imbalance, passenger loading and the wind effect. Before entering the more open water, the pilot had momentarily turned the aircraft into wind and was satisfied with the level of the wings and water handling. While the pilot attempted to observe the performance of the right float a number of times, he found it difficult to see the float from the left side of the aircraft. During the outbound taxi, the front passenger had advised the pilot that the right float was low in the water and had water breaking over it. The pilot reported that he only became concerned about the ability of the floatplane to stay afloat after the encounter with the wake of the cruise boat. At that stage he considered that beaching the floatplane was impractical due to the unsuitability of the adjacent coastline.

The front passenger later stated that the right float was basically submerged by the time the wake from the catamaran had been negotiated. He also stated that there were two round holes of approximately 30 mm diameter on the top of the right float that allowed water to enter the float. This was likely to have been the access holes for the smaller diameter bilge tubes. The access holes are normally sealed with a removable bung. The pilot stated that one or two bilge tubes were missing from their holes in the right float. Following discussions with the pilot and other company personnel, the investigation was unable to determine the point in time when the right float bungs became separated from the floats.

The passengers stated that the operator's personnel had briefed them on life jacket use when they were checked in for the flight. The pilot had also given the passengers a pre-departure briefing that included the location of the life jackets. A life jacket was stowed under each of the seats.

Civil Aviation Order (CAO) Section 20.11, Parts 5.1.4 and 5.1.5 describe the requirements for the equipping of floatplanes with life jackets. Part 5.1.8 describes the requirements for the wearing of those life jackets and states, in part: `However, occupants need not wear life jackets when the aircraft is taking-off or landing at a aerodrome in accordance with a normal navigational procedure for departing from or arriving at that aerodrome, and occupants of aeroplanes need not wear life jackets during flight above 2000 feet above the water.' Aerodrome is defined in Aeronautical Information Publication Australia, Amendment 33, as `A defined area of land or water (including any buildings, installations and equipment) intended to be used either wholly or in part for the arrival, departure and movement of aircraft.'

A fuel spill of approximately 100 litres occurred during refuelling of the South African registered Boeing 747-312 aircraft on the international terminal apron at Perth airport. Eighty minutes later, the Aviation Rescue Fire Fighting Services (RFFS) observed fuel venting from the right wing of the aircraft as it commenced a take-off roll on runway 21, for a flight to Johannesburg, South Africa.

The fuel spill at the terminal was due to the refuel valve in the number 4 reserve tank failing to shut off. The tank became overfilled because of a faulty quantity indicator at the refuelling station panel. Fuel overflowed from the reserve tank into the fuel tank vent system and then spilt onto the apron from a ram air scoop located near the wingtip. The tank vent system vented the fuel tanks to atmosphere by a series of tubes from the fuel tanks, to a surge tank located in the outboard section of each wing. The surge tank vented to atmosphere through a flame arrester and the ram air scoop.

The aircraft refuelling system included an overfill protection system whereby if 75 mm of fuel overflowed into the surge tank, a float switch operated, which closed all refuel valves. The overfill protection system could be disabled by pulling the appropriate circuit breaker in the main equipment centre within the lower forward fuselage.

During the period from 7 December to 30 December 2001, the Perth RFFS attended six other fuel spills ranging from 20 to 100 litres from aircraft used by the same operator. Those spills involved five B747 aircraft (including ZS-SAJ) and were due to the failure of the refuel valves to shut off during refuelling operations.

In 1998, the United States Federal Aviation Administration (FAA) issued an airworthiness directive, AD 98-20-40, that required the replacement of fuel quantity indication system (FQIS) electrical wiring outside of the fuel tanks and surge tank on older versions of the B747 aircraft. The modification was intended to prevent arcing of the FQIS wiring or probes due to electrical transients induced by electromagnetic interference or electrical short circuit conditions.

The five aircraft involved in the fuel spills at Perth airport had been fitted with a transient suppression device that was approved as an alternate means of compliance with the airworthiness directive. The device had caused problems with the FQIS, including incorrect calibration of the refuelling system that resulted in the aircraft being loaded with an incorrect amount of fuel or the fuel tanks being overfilled.

The spillage of fuel from the tank vent system during the eight occurrences indicated that the overfill protection system circuit breaker was pulled during the refuelling operation to work around the calibration problem. The work around enabled refuelling operations to continue and prevent any delay to the departure of the aircraft. If some fuel remained in the surge tank after completion of refuelling operations, it could vent to atmosphere from the ram air scoop during the take-off roll, as was observed on 17 December 2001.

Following the fuel spills, the operator carried out rectification work on the five aircraft, including the checking and changing of fuel system components, the replacement of FQIS wiring harnesses, and the re-calibration of the system. The operator also implemented the local safety actions listed below and no further fuel spills were reported.

The pilot of the Cessna 185 Floatplane, with five passengers on board, was making a water departure for a charter flight. The pilot positioned the floatplane for a take-off into a north easterly wind of 15 kts that was gusting to over 20 kts. The take-off path was over a sand spit, approximately 50 ft above the water level. To the north, and left of the take-off path, was a steep, rocky headland that rose to a height of approximately 300 ft above mean sea level.

The pilot reported that he had selected 20 degrees of flap and applied maximum power for take-off. The aircraft became airborne after a short run and the pilot climbed it at an indicated airspeed (IAS) of 70 kts. At about 200 ft the pilot reduced engine power to 25 inches of manifold pressure and 2,500 RPM. The pilot reported that just after he reduced power, the aircraft encountered turbulence and started to descend rapidly. He turned the aircraft left, away from the spit, with the intention of regaining altitude over the water before he attempted to cross the spit. However, the aircraft continued to descend, and the pilot decided to land straight ahead. The aircraft contacted the water and bounced, then ran aground on the beach and overturned.

The pilot reported that he exited through a window and instructed the passengers to evacuate quickly, as there was a possibility of fire. The passengers reported that they were entangled in their seat belts and had difficulty releasing the buckles. A small child was being held by a passenger and another passenger was temporarily restrained by clothing that became caught on the right control yoke.

The load chart for the flight showed that the aircraft was 31 kg below its maximum take-off weight. The pilot commenced the take-off with a take-off distance of approximately 1,100 m, which exceeded the minimum take-off distance of 1,000 m stipulated by the aircraft's flight manual. However, this take-off distance was less than the 1,300 m pilots were directed to use by the operator's Authorised Landing Area (ALA) register. The pilot reported that he had not used the full length available as previous take-offs that day, from the same point in lighter winds, had been uneventful. He considered that the increased headwind component would have improved the take-off performance and climb gradient of the aircraft.

The ALA register also stated that a north-easterly wind required a climb over the spit to avoid turbulence in the lee of the adjacent headland. Another warning in the operator's ALA survey report cautioned "Dumping will be encountered on the lee side of the headland especially in the north easterly winds".

A fact sheet on mountain wave turbulence that accompanied a recent ATSB report (Occurrence 200104092) involving mechanical turbulence stated, in part:

"Flowing air near the ground is forced up the windward side of any elevated barrier and then sinks down the leeward side. Air flowing at speeds greater than 20 kts produces seriously turbulent air and significant downdrafts on the leeward side."

That situation was referred to as "dumping" in the operator's ALA survey sheet. The pilot reported that he hadn't encountered severe "dumping" during any previous take-offs.

The fact sheet also stated, in part:

"In addition to generating turbulence that has demonstrated sufficient ferocity to significantly damage aircraft or lead to loss of aircraft control, the more prevailing danger to aircraft in the lower levels in Australia seems to be the effect on a aircraft's climb rate. General aviation aircraft rarely have performance capability sufficient to enable the pilot to overcome the effects of a severe downdraft generated by a mountain wave, or the turbulence or windshear generated by a rotor."

The Cessna 185 Pilot's Operating Handbook (POH) procedures for both normal take-off and short field take-off recommend that once clear of any obstacles, the pilot retract the wing flaps and select full throttle and 2,700 RPM. Operations manual data produced by the operator listed the climb power setting as 25 inches manifold pressure and 2,700 RPM, with a footnote that the information be used as a guide only and that the user refer to the POH and Flight Manual. The aircraft's flight manual did not provide guidance on take-off procedure or associated power settings. The climb power setting of 25 inches manifold pressure and 2,500 RPM, selected by the pilot when the aircraft reached approximately 200 ft, delivered only 81 per cent of the available power.

The pilot reported that he had been encouraged by the operator to reduce power as soon as possible after take-off as a noise reduction technique. The Chief Pilot stated that a power reduction early in the climb was demonstrated during training to reduce the noise impact and to reduce engine wear. The Chief Pilot also stated that, during training it was emphasised that power reductions should only be made when clear of obstacles and when terrain had been cleared. It was also stressed that when required, full power should be used, at the pilot's discretion.