A Fairchild SA227-AC (Metro) aircraft landed on runway 34R, with an instruction to exit onto taxiway Tango 1 and taxi via taxiway Juliet. The pilot contacted the surface movement controller (SMC) while approaching a mandatory holding point on taxiway Juliet, and was instructed to taxi via taxiway Bravo and hold short of runway 25. The pilot read the instruction back correctly. That instruction required the pilot to continue ahead on taxiway Juliet, passing the entry to taxiway Charlie before turning right into taxiway Bravo.

The tower controllers subsequently observed the Metro taxiing along taxiway Juliet, past the entry to taxiway Bravo, towards runway 34L, which lay a short distance beyond taxiway Bravo. At that time, a Boeing 737 (B737) was touching down on runway 34L. The SMC instructed the pilot of the Metro to stop. As there was no reply, the instruction was immediately repeated, and subsequently acknowledged. The Metro was stopped at the edge of runway 34L, beyond the runway holding point. The pilot of the B737 was also instructed to stop immediately, but the aircraft was too close to the taxiway Juliet intersection to comply. The B737 was steered to the left of the runway centreline to increase separation from the Metro, subsequently passing about 25 m in front of that aircraft, at about 80 kts.

The occurrence happened at night in fine conditions; there were no works taking place in the area; and all relevant taxiway lights, runway holding point lights and movement area guidance signs were reported by the air traffic controllers to have been functioning normally. However, when subsequently interviewed, both pilots asserted that the runway 34L holding point lights on taxiway Juliet were not illuminated. Shortly after the incident an airport safety officer had been requested to conduct an inspection of the ground lighting in the occurrence area. All lighting, including the holding point lights on taxiway Juliet protecting runway 34L, were observed to be functioning normally.

An investigation established that the pilot flying the aircraft was undergoing command training under the supervision of a training captain. A practice Instrument Landing System (ILS) approach had been flown, during which the pilot under training experienced difficulties in maintaining the required flight tolerances. After landing, the pilot correctly obtained and read back the taxi clearance. However, he subsequently failed to notice that the aircraft had passed taxiway Charlie and was approaching the entrance to taxiway Bravo. Believing he was now approaching taxiway Charlie, the pilot continued to taxi along taxiway Juliet, expecting to see the entry to taxiway Bravo.

At about that point, the training captain, noticing that the aircraft had just passed the entry to taxiway Bravo, looked towards the pilot to ask where he was going, but immediately noticed the lights of a landing aircraft on runway 34L. Concerned about the proximity of the other aircraft, he immediately instructed the pilot under training to stop, which coincided with similar instructions from the SMC.

During discussions with the crew of the Metro, it became apparent that, after landing, the pilot under training had been concerned with his performance during the practice ILS approach, and had initiated a brief discussion with the training captain at about the time the aircraft had been taxiing along taxiway Juliet.

Both pilots, who were very familiar with the layout of Sydney Airport, also indicated that the movement area guidance signs (MAGS) were somewhat confusing when indicating the entry to taxiways. However, the pilot under training said that normally he did not refer to the MAGS because of his familiarity with the taxiway layout.

The handling pilot was undergoing a scheduled 6-monthly proficiency check in the Learjet, under the supervision of an experienced instructor who occupied the right control seat. The flight was planned to depart from Essendon and proceed to the Ripley locator, for an entry into the holding pattern, before making a locator approach to Avalon. Three touch-and-go circuits were planned at Avalon, including one 700-ft asymmetric low-level circuit following a simulated engine failure at V1. The aircraft was then to return to Essendon via the Plenty locator for an instrument landing system (ILS) approach.

The instructor briefed the exercise in detail and, because the pilot under check had low experience in the Learjet, it was decided that the instructor would handle all radio communications and conduct the necessary check sequences. The instructor also indicated that it was company policy for the aircraft be landed with less than full flap during an asymmetric landing. The aircraft was to be landed with flap 20 at Vref +10 kts.

The flight proceeded normally up to the point of the simulated engine failure at V1. When the instructor simulated a right engine failure by placing the thrust lever in the IDLE position, the aircraft drifted to the right. Intervention by the instructor enabled the aircraft to return to balanced flight. The handling pilot continued to carry out the 700-ft circuit in the after-take-off configuration of gear UP and flap 8. Flap 20 was selected during the base turn. The aircraft was flared normally with both thrust levers in the IDLE position. As the aircraft settled, a slight vibration was noticed, and both pilots became aware that the landing gear was still selected UP. Go-round power was applied and the aircraft climbed away. The landing gear was cycled normally and the aircraft returned for a full stop landing. A subsequent inspection of the aircraft showed that the only evidence of a runway strike was abrasion of the lower fuselage mounted very high frequency (VHF) blade antenna.

A subsequent investigation revealed that the pilot under check was allocated one hour of Learjet flying every 3 months. The instructor had selected the flight sequences to give the pilot the maximum handling exposure in the limited time available. In doing so, the normal two-crew, challenge and response routines were abandoned and the checks had to be accomplished by the instructor alone. The instructor became distracted by the asymmetric handling issues, and the demands of the low-level circuit, subsequently forgetting the relevant downwind and pre-landing checks. The handling pilot, who had been absorbed with controlling the aircraft, had lost situational awareness and did not notice the lack of check procedures by the instructor, or the lack of a positive gear-down indication.

The approach had been carried out with flap 20 extended, rather than full flap (flap 40), because the operator had previously experienced a partial loss of control during training when attempting an asymmetric go-around at flap 40. However, with flap 20 selected, the landing gear warning system was inhibited, contributing to the late realisation that the landing gear was not extended. The flap 20 asymmetric approach configuration was not in accordance with the manufacturer's flight manual recommendations.

A Boeing 767 (B767) was en route from Auckland to Hong Kong on air route B333. The crew had been cleared to conduct a cruise climb from FL310 to FL330. While FL310 was a standard level for the track being flown, FL330 was not. A Boeing 737 was en route from Sydney to Port Vila on air route B580. The crew of this aircraft had been cleared to, and was maintaining FL330, which was a standard level for their track. The routes cross at LEMIB a waypoint located approximately 490 NM east of Brisbane. The aircrafts' estimates for LEMIB were within three minutes of each other.

Five minutes prior to reaching LEMIB the crew of the B767 received a traffic alert and collision avoidance system traffic advisory warning. The traffic alert and collision avoidance system indicated that an aircraft was passing from left to right 900 ft above the level of, and 12 NM ahead of the B767. The required separation standard was 2,000 ft vertically.

Air traffic controller training was being conducted at the control position responsible for the area at the time of the occurrence. Following a query by the B767 crew regarding the crossing aircraft to air traffic control and a check of the flight progress strip data it was established that a separation standard had not been applied between the aircraft. There was a breakdown of separation.

Organisational aspects

The trainee was a group leader in the Brisbane Centre responsible for the management of the Tops/Ocean/West group. The group was divided into a number of sectors. Tops consisted of sectors 11, 11k and 12. West consisted of sectors 5 and 5D while Ocean had sectors 8, 8O and 10. Sectors 5D and 8O were radar sectors while all the other sectors were procedural control sectors except sector 11K which was a composite radar/procedural sector.

The group leader had previously held ratings and endorsements for all Tops sectors but had let two endorsements lapse due to workload and retained only the sector 11K endorsement.

The Ocean sectors were to be the first of the group to transition to The Australian Advanced Air Traffic Control System. The Ocean sectors had limited experienced staff plus there were other concerns for management that they believed could be suitably handled by the group leader becoming part of the Ocean teams. He also believed that if he obtained Ocean sector ratings he would be able act as a relief controller if required. Consequently, it was agreed that the group leader would transition with the Ocean sectors.

The group leader intended to undergo training to obtain the appropriate endorsements for the Ocean sectors. On completion of training he would function as one of the three Ocean team leaders as well as retaining group leader responsibility for those sectors. The En-route manager was to assume group leader responsibilities for the Tops and West sectors during the transition. To enable the group leader to commit himself totally to the training, an interim group leader was to be appointed to manage the group. The interim leader took over the group in the week immediately prior to the occurrence.

The Ocean sector staff had, and were, undergoing considerable changes due to: the reorganisation of the sectors; developments relating to contingency plans for Papua New Guinea airspace; management of Honiara airspace; and the transfer of the provision of directed traffic information from flight service international to the sectors and changes required for The Australian Advanced Air Traffic Control System transition. There were also a number of staff management issues that limited the options available to the group leader to meet operational demands.

Training plan

The Ocean sectors had a comprehensive training plan with workbooks for trainees and a training guide for the controller supervising the training. However, the supervisors training guide was unapproved and was in draft form only. The training guide and workbook were developed with the intention of providing a basis for ab-initio training. Training normally commenced with the trainee undertaking four weeks familiarisation at the sector operating positions followed by four days of classroom work, approximately one month in the simulator and finally six weeks of on the job training. During the on the job training phase the trainee would be assessed for competency by the supervising controller.

As the group leader already held radar and procedural ratings and an endorsement for sector 11K he elected to rationalise the ab-initio training program to reduce the time spent training. This aspect was in accordance with Airservices Australia's Civil ATS Operations Administration Manual which described "refresher training" for controllers as:

"training which focuses on change in a person's required competence and includes training concentrating on what a person once knew; what a person should (or does) know but hasn't been applying; and what a person hasn't had an opportunity to apply."

The Civil ATS Operations Administration Manual also detailed "local training strategies which recognise refresher training responsibilities include (but are not limited to):

1. personal study of material, including videos, collated and provided by at the direction of team leaders or line mangers;
2. use of simulator sessions, either specific to refresher training topics or included in ongoing training; and
3. use of computer based training (CBT)."

The group leader had reviewed the training material for sector 8 but had not undertaken any classroom or simulator training for the sector. Due to other training commitments the simulator was not immediately available. He planned to join the scheduled Ocean simulator-training program at lesson ten (three weeks after the date of the occurrence) and to complete the lessons through to 23. During the interim period the group leader was to undertake familiarisation training under supervision. He had discussed his training plan with one of the Ocean team leaders responsible for training. There was no process to assist rated controllers intending to train for other ratings/endorsements to develop a suitable training plan.

Supervising controller

A supervising controller had been appointed to oversee the training of the group leader. The group leader's training commenced two days prior to the occurrence. During that time he and the supervising controller had spent approximately three hours together on the first day, none on the second and three hours on the morning of the day of the occurrence. The interruptions to the group leader's training were due to a prior commitment on the first day and the lack of a training position as a result of another controller undergoing familiarisation on the second day.

After spending three hours together on the morning of the occurrence the group leader and the supervising controller conducted a handover of sector 8 to enable them to take a rest period. Subsequently, the supervising controller returned to the console and assumed responsibility for sector 8O, the radar sector.

At 1100 Eastern Standard Time the group leader was waiting at the console expecting the next rostered controller to takeover sector 8O to enable the supervising controller to train the group leader on sector 8. A recently arrived controller offered to supervise group leader on the console instead of taking over sector 8O. Subsequently, this controller and the group leader assumed responsibility for sector 8. The controller had recently completed a stint as a supervising controller for another trainee and had considerable training experience. The nominated supervising controller for training the group leader remained on sector 8O.

The controller was not aware of how much training the group leader had completed and was therefore not aware of the latter's level of knowledge in the position. They did not conduct a pre-training brief to discuss learning aspects to be addressed during the session.

Sector 8 was the only procedural sector that used controller pilot datalink facilities to communicate with flight crews. Between 10% and 20% of all the flights operating through the sector used the controller pilot datalink. As the group leader was unable to operate the controller pilot datalink the controller was required to operate the facility. The controller was also directing and explaining the operation of sector 8 to the group leader while reviewing the flight progress strips for conflictions.

The controller and the group leader were at the position for approximately two hours during which the number of aircraft under their control steadily increased. The group leader noted a number of procedures that were different to what he expected to experience and he found it increasingly difficult to maintain an appreciation of the traffic situation. During this period it became apparent to the controller that the group leader was unfamiliar with the operation of the position.

Just prior to the occurrence the group leader received a request for a clearance from the pilot of an aircraft to enter the oceanic control area on climb to FL250. Because of the proximity of the aircraft to other flight information region boundaries the controller had to coordinate with Nadi and Auckland Centres prior to issuing a clearance. At about the same time, a flight information region boundary position report was received on the controller pilot datalink from a flight. The controller should have transferred this flight to Nadi Centre prior to the position but had not instructed the crew to transfer. Consequently, the position report had to be coordinated by voice intercom.

Flight progress board management

Details of the B737 were annotated on a blue flight progress strip and the sector 8O controller had coordinated the flight at FL330. The B767 flight was on a buff flight progress strip. Blue and buff coloured flight progress strips were used to differentiate between eastbound and westbound flights respectively. Coordination on the B767 was received from Auckland Centre and a clearance for the crew to conduct a cruise climb in the block level FL310 to FL330 was concurred. Requests by crews to conduct a cruise climb were regularly received and approved by the sector 8 controllers.

The recognition and resolution of potential conflicts at positions in the sector where tracks crossed was a regular part of a controller's task. The crossing point of the aircrafts' tracks, LEMIB was not annotated on either flight progress strip. After flight progress strips were activated by a departure report or coordination from another air traffic service unit they were passed to the sector 8 controller for placement on the board. The controller would place flight progress strips under an appropriate designator and then review all flight progress strips for conflictions. Conflicting flight progress strips would then be "cocked" to highlight a problem for subsequent action. Controllers "cocked" a flight progress strip by partially moving a strip out of the display bay.

If the controller identified that there was a potential conflict at a crossing point like LEMIB, a separation standard would be calculated and the respective flight progress strips would be annotated with the position. Once the separation procedure had been applied the flight progress strips would be returned to the bay. In the occurrence the flight progress strips for the aircraft were placed in the bay under the same designator without being cocked. The investigation did not establish why the flight progress strips were placed in the bay without being actioned.

Controller pilot datalink facilities

When the controller pilot datalink had been introduced a simulator had been provided to assist in the training of controllers. The controller pilot datalink simulator had subsequently been removed from the centre following training of the initial group of controllers required to operate the system. There were no facilities to assist controllers to learn how to operate the system prior to conducting the on the job training phase of their training. There was no controller pilot datalink reference material in the training guides. The group leader was not familiar with the operation of the controller pilot datalink.

With the introduction of the controller pilot datalink, two additional positions on sector 8 had been established for a controller to specifically operate the facility during the morning and afternoon shifts. At the beginning of 1998 these positions were disestablished to provide an additional team leader and to enable a controller to undertake operational development tasks. Sector staff had discussed the decision to remove the dedicated controller pilot datalink controller and believed that a controller could adequately manage both the controller pilot datalink and the sector 8 position. There was no workload or safety review conducted prior to amending the roster.

Team management

On the day of the occurrence there were no team leaders rostered for duty to oversee the management of the sector. A full performance controller was fulfilling the team leader functions. This controller had not completed team leader training.

Sector 8

Sector 8 was a procedural sector managing the Class A oceanic controlled airspace east of the coast of Australia, extending to the flight information boundary with New Zealand and Nadi, from just south of Tasmania to a line joining Brisbane and Port Vila. The operation of the sector was considered by controllers to be significantly different from other procedural sectors because of the inclusion of the controller pilot datalink and the different separation standards and procedures used for oceanic control compared to sectors over continental Australia.

Operating position

The sector 8 operating position consisted of a console with a flight progress strip display with the controller pilot datalink keyboard and monitor located on a table on the left side of the console. The sector 8 controller operated the controller pilot datalink and managed the separation of aircraft using flight progress strips placed under location designators on the board. The layout of the facilities required the controller to turn 90 degrees to the right each time the controller pilot datalink was operated.

The sector 8O radar position was located to the left of the procedural console and a map display was fixed to the floor in front of, and midway between both operating positions.

The layout of the operating positions and the additional facilities only enabled a single controller to sit and operate sector 8. Controllers supervising training were required to sit or stand behind the trainee.

The De Havilland Dash 8 was tracking inbound to Tamworth via the 040 radial of the Tamworth VOR (a radio navigation aid) at 3,500 ft in accordance with air traffic control instructions. Meanwhile, a TB10 Tobago was about to depart Tamworth via the 018 VOR radial, a track that would require the Tobago to turn across the inbound track of the Dash 8. Air traffic control had decided to limit the initial climb of the Tobago to 2,500 ft in order to ensure vertical separation with the Dash 8.

The aerodrome control task was being performed by a trainee controller under the supervision of a rated controller. The pilot of the Tobago was instructed to "line-up" and given an altitude restriction of 2,500 ft, which was read back by the pilot. However, the readback was not clear and the aircraft subsequently took off with both the trainee controller and the rated controller uncertain as to the actual altitude read back by the pilot, who was from a non-English speaking background and had an accent that was, on occasions, difficult to understand. It was subsequently determined that the pilot of the Tobago had understood the controller to say 3,500 ft, and that was the altitude he had read back to air traffic control. The crew of the Dash 8 were given traffic information on the position of the Tobago by air traffic control and commenced a look-out for that aircraft.

Because both controllers were unsure that the 2,500 ft restriction had been correctly acknowledged, it was agreed that the trainee controller would request the pilot of the Tobago to confirm that he was maintaining that altitude. Before that could take place, the pilot of the Tobago asked the controller to confirm his assigned altitude. Again, the transmission was not easy to understand. The trainee controller confirmed 2,500 ft and passed traffic information on the Dash 8 at the same time. The only reply from the pilot of the Tobago was the word "affirm" and his callsign.

In fact, the Tobago had been maintaining 3,500 ft, and it was that later transmission from air traffic control that made the pilot realise he should have been maintaining 2,500 ft. He commenced an immediate descent from 3,500 ft, but did not make any radio transmission to that effect.

The crew of the Dash 8 heard the exchange between air traffic control and the pilot of the Tobago. At almost the same time, they saw the Tobago about 400 m ahead, at the same level. They commenced an immediate descent then realised the Tobago was moving to their right. The aircraft passed with a horizontal separation of approximately 200 m, and no discernible vertical separation. The required standard was 1,000 ft vertical separation until the aircraft had passed.

While flying a coupled instrument landing system (ILS) approach to runway 35 at Canberra, the crew received a ground proximity warning system (GPWS) "terrain" warning at 470 ft above ground level. As the aircraft was in visual conditions at the time, the crew elected to continue the approach.

The crew reported that, at the time of the warning, the aircraft was established on the ILS glideslope and descending at 650 ft/min. However, the T-VASIS indicated one dot low. Immediately prior to the warning, the radio altimeter indication rapidly increased, and then decreased, apparently triggering the warning.

On 8 June 1998, at 0855 EST, the pilot of a Boeing 737 air transport aircraft reported receiving an emergency locator transmitter (ELT) signal about 25 NM west of Melbourne. The pilots of several other aircraft also reported hearing the emergency beacon signal on 121.5 MHZ. At 0949 the Australian search and rescue centre received the distress signal via a satellite and had a possible location in the Mount Macedon area. At 1012, VH-SAR, a dedicated search aircraft, departed Moorabbin tasked with locating the beacon using a homing device. The pilot of SAR reported that the cloud tops over Mount Macedon were about 4,500 ft. By about 1245, Cessna 210, UNH, was assessed to be the missing aircraft. UNH had been conducting a no search and rescue (NOSAR), visual flight rules (VFR) flight from Bendigo to Moorabbin. At 1302 a ground party discovered the wreckage of UNH on the north western slope of the Mount Macedon feature at a ground elevation of about 2,840 ft above mean sea level (AMSL). The aircraft had cut a 100 metre swath through tall trees in the direction of 060 degrees magnetic. Both wings and the tail plane were torn off before the fuselage impacted sloping ground.

Melbourne radar recorded only one minute 35 seconds of UNH's flight path. UNH had maintained a steady track of about 160 degrees magnetic at 122 kts groundspeed from Kyneton before turning east in the Woodend area. Shortly thereafter the aircraft turned onto an east north easterly heading before disappearing off radar. Briefly during the recorded easterly turn, the radar recorded a groundspeed of 153 kts. The groundspeed then decreased to 77 kts just before the aircraft disappeared off the radar screen. The forecast wind at the time was 180 deg (true) at 20 kts at 2,000 ft AMSL, and 170/20 kts at 5,000 ft. There was no altitude recorded for UNH on the radar tape.

A few minutes before the accident a qualified pilot, on the ground 6.5 km S of Kyneton, witnessed an aircraft meeting the description of UNH. This aircraft was flying SE at about 500 ft above ground level (AGL) just below the cloud. The weather to the north of Kyneton was clear sunshine. The cloud line was from Kyneton to the northern edge of Woodend. The Mount Macedon feature was obscured by cloud. The aircraft maintained a steady track towards Gisborne. He reported that the aircraft's engine sounded normal. He lost sight of the aircraft as it neared Woodend. At 0829 two other people heard an aircraft flying very low over their house near Woodend but they did not see it. They described the weather conditions as heavy fog to below the tops of tall trees. Another qualified pilot witnessed the weather from the ground in the Woodend area at about the time of the accident. He described the cloud as low stratus in the form of fog. He also said that Mount Macedon was not visible due to cloud coverage.

The ground level at Kyneton was about 1700 ft AMSL and at Woodend about 1900 ft, compared to about 2,840 ft at the accident site.

The Bureau of Meteorology described the weather conditions as: "Rain showers and drizzle accompanied by patchy low cloud, generally widespread on and south of the Great Dividing Range mainly east of 144 deg E, while conditions to the north were quite clear due to the drying out of the airstream". There was no cloud and excellent visibility at Bendigo and visual meteorological conditions (VMC) prevailed at Moorabbin. At Melbourne airport, 30 minutes after the accident, there were three OKTAS of cloud at 300 ft AGL, seven OKTAS at 800 ft, plus drizzle.

The 37-year-old pilot held a private pilot's licence, issued in August 1982. He was qualified to fly the Cessna 210, UNH, which he owned. He held a valid class two medical certificate with a restriction of needing vision correction to meet the near vision standard. No evidence was found that the pilot was suffering from any medical condition which could have contributed to the accident. Vision correction spectacles were found at the accident site and a taxi driver, who drove the pilot to Bendigo airport on the morning of the accident, stated that the pilot was wearing spectacles. The pilot had logged total flight time of 340 hours, comprised of 120 hours dual and 220 hours as pilot-in-command by day. He had never qualified for an instrument rating. He had logged only eight hours of simulated instrument flight time but was reported to have gained more simulated instrument flight rules (IFR) experience by practising with a safety pilot in accordance with the provisions of Civil Aviation Regulation 153. He was reported to have accrued 1.5 hours simulated IFR flight time as recently as 30 May 1998 between Mildura and Leigh Creek. His last biennial flight review was conducted on 28 May 1998. From 29 May 1998 until 8 June 1998, the pilot had logged 17 hours as pilot-in-command of UNH. He had shared the flying with another private pilot from Moorabbin to the Northern Territory to Bendigo. He was on the last leg of the return flight from the Northern Territory to Moorabbin when the accident occurred.

Late on the afternoon of 7 June 1998, the pilot, his companion pilot and two passengers had arrived at Bendigo in UNH. They refuelled the aircraft with 243 litres of AVGAS. Their intention was to continue the flight to Moorabbin that day but as there was some doubt about reaching Moorabbin before last light, the pilot elected to remain overnight at Bendigo and to continue the flight on 8 June 1998, weather permitting. For reasons unrelated to the accident, the companion pilot and one of the passengers elected to be driven by road to Melbourne on the night of 7 August 1998.

At 0644 on the morning of 8 June 1998, the pilot telephoned an Airservices Australia briefing officer and was given weather details for the proposed flight from Bendigo to Moorabbin. He did not submit a flight plan or a search and rescue time (SARTIME) to the briefing office for the flight. A flight log sheet, found in the aircraft after the accident, confirmed that the pilot had planned the flight from Bendigo to Moorabbin via Kyneton, Mount Cottrell and Point Ormond. On the recent flight legs from Victoria to the Northern Territory and return the pilot had nominated SARTIMEs to Airservices Australia.

For the trip to the Northern Territory and return to Victoria, the pilot had used his portable Garmin 195 global positioning system (GPS) to assist with navigation. He was reported to have been quite competent with its use. Another pilot, who had flown UNH in the past, using a similar portable GPS, reported experiencing erratic GPS tracking in the Mount Macedon area. However, on 30 June 1998 Airservices conducted flight test trials in the Mount Macedon area using a Gulfstream Commander 1000 test aircraft fitted with five GPS receivers. One GPS was a handheld Garmin GPS 90 with an external antenna, comparable to the GPS used in UNH. No fault was found with GPS tracking in the Mount Macedon area at the time of the trials.

The aircraft was examined at the accident site before being retrieved to Moorabbin airport where it was subjected to detailed examination. Evidence was found at the accident site that there was fuel on board the aircraft at impact. Damage sustained by the engine crankshaft confirmed that the engine was producing power at impact. No fault was found with the airframe or engine which may have contributed to the accident. Damage sustained by instruments and avionics was consistent with impact forces.

A Piper Archer and a Piper Tomahawk collided at an altitude of about 1,200 ft as the Archer was tracking to enter the crosswind leg for a landing on runway 34 at Hoxton Park aerodrome. The collision occurred in fine and clear conditions, about 0.5 NM east of the upwind end of the runway. Both aircraft were being flown under the visual flight rules (VFR). The pilot of the Archer was able to maintain control of his aircraft and make a successful approach and landing on runway 34, although the nose landing gear had been substantially damaged in the collision. The aircraft was stopped on the runway, resting on the collapsed nose landing gear.

The collision was observed by witnesses who reported that the Tomahawk immediately spiralled down and crashed into an unoccupied house in a suburban housing area. Both occupants were fatally injured. There was no fire and there were no injuries to persons on the ground.

Operations at Hoxton Park are not directed by air traffic control services and rely on pilots seeing and avoiding other aircraft. The aerodrome is located within a common traffic advisory frequency (CTAF) area, extending to a 2 NM radius from the aerodrome and to a height of 1,700 ft. Pilots of radio-equipped aircraft intending to operate within that area are required to make a radio broadcast when approaching the CTAF boundary. That broadcast must include aircraft callsign and type, position, level, and intentions. No other radio report is required prior to landing.

The pilot of the Archer reported that he had made a broadcast on the CTAF when 3 NM inbound to Hoxton Park. He then descended to 1,200 ft and tracked to join the crosswind leg for runway 34, making a "joining crosswind" broadcast while still approaching the upwind end of the runway. He saw another aircraft turning onto crosswind after taking off from runway 34, and a second aircraft on the downwind leg. At about that time, he saw to his left the underside of an aircraft turning to the left, about 50 m away, but skidding towards him at about the same altitude. The pilot of the Archer said he started to turn to the right to avoid a collision, but there was a bang just moments after he first saw the aircraft. He briefly glanced back and saw the aircraft spiralling down to the left. It appeared to him that the outboard end of the right wing of the other aircraft was bent upward at about 45 degrees and that the aircraft appeared to be totally out of control. As he was concerned for the safety of his own aircraft, he concentrated on landing as soon as possible. At no stage prior to the accident was he aware of the presence of the Tomahawk.

Investigation of the wreckage of the Tomahawk indicated that the engine had been torn out during the impact with the house. There was major disruption to the aircraft structure and cockpit area. Small sections from the right wing were scattered about the immediate neighbourhood. The cockpit instruments and controls were too severely damaged to provide any useful information. The very high frequency radio was selected to the CTAF frequency. There was no evidence of any pre-existing defects or abnormalities with either aircraft that may have contributed to the accident.

A metallurgical examination of a section of the right outboard wing from the Tomahawk revealed that a propeller blade of the Archer had first cut through the wing-tip plastic moulding near the trailing edge. The propeller had then cut through the wing at about the mid-chord area before finally striking the leading edge. The action of the propeller blades striking the wing resulted in disruption of the wing structure, with an associated upward bending of the outer section of the wing.

Sydney airport and associated airspace was being operated in accordance with Mode 9 of the Long-Term Operating Plan. A Boeing 737 (B737) departed runway 34R for Melbourne and was cleared initially to 5,000 ft on a MARUB ONE standard instrument departure (SID), with a Wollongong transition. The SID required the crew to intercept and track via the 075 Sydney VOR radial to 15 NM (waypoint MARUB), and to then turn right and track 144 degrees until passing 9,000 ft.

At the same time, another B737 inbound to Sydney on a CHEZA THREE standard arrival route (STAR) for a landing on runway 34R had passed waypoint WHALE, located 20 NM east of Sydney, and was maintaining 7,000 ft in accordance with its clearance.

The Departures South controller cancelled the 5,000 ft altitude restriction for the departing B737 and issued a clearance for the aircraft to climb to Flight Level 280. The 5,000 ft restriction would have assured separation with the inbound B737. When the altitude restriction was removed, the controller relied on monitoring the flight paths of both aircraft and intervening, if necessary, to maintain separation.

When the departing B737 turned right to track 144 degrees in accordance with the SID, there was a breakdown in separation between the two aircraft. Separation was reduced to 2.5 NM horizontally and 500 ft vertically, whereas the required standard was either 3 NM or 1,000 ft. Traffic information was passed to the crew of the departing B737, who sighted the other B737 while passing behind it.

The Departures South controller was relatively inexperienced, having held a control rating in the Sydney Terminal Control Unit for only three weeks. The controller was distracted from the monitoring role by coordination activities with Bankstown control tower, and by radio transmissions to other aircraft. The controller also considered himself to have been fatigued as a result of local rostering practices.