Circumstances

Panther Cougar Section [4 X Macchi 32] were completing operations in Restricted Area R527. Williamtown air traffic control [ATC] commenced co-ordination procedures with Sydney Sector 2 for clearance to transit civil airspace in order to recover the section to Williamtown.

Due to Sydney ATC internal co-ordination requirements, Sydney Sector 2 were unable to issue a clearance immediately and themselves commenced co-ordination with Sector 1 and arrivals South. At the same time Sector 2 advised Williamtown ATC to contact Sector 1 direct for further instructions.

Williamtown ATC then contacted Sector 1 only to be told to contact Arrivals South. After establishing contact with Arrivals South, Williamtown were then told to contact Sector 2.

As a result of this uncertainty the 4 X MC32 aircraft were diverted clear of civil airspace by Williamtown ATC and the extra flight time resulted in the aircraft landing with eight minutes endurance remaining.

Significant Factors

1. The internal co-ordination requirements for Sydney ATC were cumbersome and unnecessarily complex.

2. The Sydney Sector 1 controller did not obey the principles of point to point co-ordination as specified in the Manual of Air Traffic Services [MATS].

Circumstances

RAAF Williamtown were operating FA18 aircraft in Restricted Areas R457 and R527. In order to return these aircraft to Williamtown at the completion of their task, it was necessary to transit civil controlled airspace under the control of Sydney Sectors 1, 2 and Arrivals.

Williamtown air traffic control [ATC] co-ordinated with Sydney Sector 1 for the recovery of two FA18 aircraft and Sector 1 issued approval and advised of civil aircraft with which Williamtown ATC needed to provide radar separation with their aircraft. Sector 1 also agreed to perform the co-ordination tasks with Sector 2 and Sydney Arrivals, which was correctly carried out.

Williamtown ATC then proceeded to recover their aircraft in accordance with the clearance issued by Sector 1, but as the FA18s were approaching civil airspace, Sector 1 advised of additional traffic VH-TAH whose track and altitude placed the aircraft in potential conflict with Shogun 1/2 [FA18].

Sydney Sector 1 believed that he had only co-ordinated an expectancy of approval with Williamtown ATC but Williamtown believed that they had received a clearance to transit the airspace.

As a result Williamtown ATC radar vectored its aircraft clear of VH-TAH and no breakdown in separation occurred.

Significant Factors

1. The co-ordination procedures for this section of airspace were complex and time consuming which led to confusion as to if an actual clearance was issued.

ASOR 9200127

Circumstances

VH-KLS departed Williamtown for Canberra at 1032 hours on a charter flight using IFR procedures. At 1040 hours the pilot contacted Sydney Flight Service and reported that he was on the 015 radial of the Sydney VOR and maintaining 6,000 ft.

The Flight Service Officer [FSO] held a flight strip on the aircraft but had received no co-ordination from Williamtown ATC. The FSO then contacted Williamtown ATC to ascertain the co-ordination required and was informed that VH-KLS had departed at 1032 hours.

There was no known conflicting traffic and therefore no breakdown in separation.

Significant Factors

1. Williamtown ATC did not co-ordinate the departure time of VH-KLS as required by the Manual of Air Traffic Services [MATS].

VH-STO [PA31] taxied at Port Macquarie for Williamtown at 0241 hours (UTC) and made his departure call on area frequency at 0246 hours.

VH-TQQ [DHC8] was enroute Sydney for Port Macquarie and passed overhead Williamtown at 0242 hours with an estimate for Port Macquarie of 0254 hours.

TQQ was under the control of Williamtown military ATC, and the controller did not pass this position and estimate to Sydney FS in the required time. As a result, the first the Sydney FS officer and the pilot of STO knew of TQQ was when the pilot of TQQ made his passing 10,000ft call on area frequency at 0247.30 hours.

The FSO immediately passed the two aircraft traffic on each other [at 0248 hours] and the Williamtown controller passed the coordination at 0249 hours, with an apology.

The two captains immediately initiated vertical separation until positive passing was established. TQQ maintained 5000ft on descent and STO maintained 4000ft on climb. This separation was established at 0249 hours, and the two crews attained a mutual sighting at 0250 hours. The pilots state that the two aircraft were on track and over the same location at the time of passing.

Weather was cloudy with some breaks and both pilots report being in and out of cloud. TQQ did remain visual throughout the lower part of its descent, but STO was in IMC most of the time.

Significant Factors

1. Williamtown ATC did not coordinate the Williamtown position report for TQQ to Sydney FS in the required manner.

2. Only appropriate and timely action by the Flight Service Officer and both crews avoided a separation incident.

The Brisbane terminal area was busy, and both aircraft were required to enter a holding pattern at Maroochydore. VH-EWG was to be the first of the two aircraft to land at Brisbane, but because the pilot had slowed the aircraft enroute, VH-TAY had already entered the holding pattern at a lower level than VH-EWG.

When a preceding aircraft left the holding pattern on descent for landing at Brisbane, the air traffic controller responsible for the holding aircraft descended VH-EWG through the level of VH-TAY without the required lateral separation. At the time both aircraft were heading in the same direction with VH-TAY travelling at a faster speed. The controller realised his mistake and instructed VH-EWG to climb. Separation was reduced to 2.5NM instead of the required 5NM. The controller was relatively inexperienced at the control position he was working and the workload at the time was high.

VH-RMH departed runway 25 and was instructed to maintain runway heading and 3,000 ft before being given a right turn. The aircraft was under the control of Sydney Departures. VH-JRY was being vectored to Bankstown by Sydney Approach South where one controller was undergoing familiarisation while being supervised by a rated officer. Approach was given a 4,000ft altitude restriction by Departures due to runway 25 being used for departing aircraft.

As VH-JRY came into the overhead Bankstown position, the Approach controller descended the aircraft without co-ordinating with Departures. When the Departures controller realised the situation, he gave VH-RMH a further right turn for separation.

Separation standards available to the controller were three nautical miles lateral or 1,000 ft vertical. Analysis of recorded radar data indicated that the closest point between the two aircraft occurred at 1422.48 hours when the vertical distance was zero and the lateral distance was 1.7nm.

The controller undergoing familiarisation qualified as an Approach/Departures controller in 1978, although he had not exercised his rating on a regular basis for nearly four years. He had recently been selected for Check Control duties on Approach/Departures.

It was the controller's first familiarisation shift where runway 25 was in use for departures and runways 25 or 34 for arrivals. He remembers being given the 4,000ft restriction by Departures and writing it on the strip, but he did not underline it (indicating the restriction). When co-ordination was received identifying the position of VH-JRY relative to radio station 2RN, he became momentarily confused as the radio mast referred to had undergone a name change since he had last actively been an Approach/Departures controller. This confusion occupied his mind until he suddenly realised that VH-JRY was in need of descent.

The controller misidentified the VH-JRY radar return as being on the western side of Bankstown, when in fact it was on the eastern side. He then forgot to co-ordinate with departures and descended VH-JRY.

The Departures controller reacted as soon as the situation was realised but not before a breakdown in separation occurred.

Significant Factors

1. The approach controller undergoing familiarisation did not co-ordinate descent for VH-JRY below the previously advised altitude limitation.

2. The rated approach controller did not exercise an adequate level of supervision.

VH-TQR [DHC8] was maintaining Flight Level [FL] 200 on the CRAVEN - Port Macquarie track on a flight from Sydney to Port Macquarie. A clearance was obtained by Sydney Sector 2 from Williamtown Air Traffic Control [ATC] for VH-TQR to transit Restricted Area R594A at and on descent from FL200. The aircraft was authorised to leave control area on descent.

RAAF Air Defence personnel were controlling MAPLE 32 [FA 18] and were instructed by Williamtown ATC to ensure that the aircraft would remain east of the CRAVEN - Port Macquarie track. During vectoring procedures, the Air Defence Controller allowed MAPLE 32 to cross this track and come into conflict with VH-TQR. The Senior Controller observed this situation and initiated appropriate co-ordination to rectify the confliction.

There was approximately two minutes delay before the exact information reached the Air Defence Controller responsible for MAPLE 32 and by the time separation was guaranteed, the aircraft had passed the point of nearest contact.

On observing the potential conflict, Sydney Sector 2 instructed VH-TQR to maintain FL190 in an attempt to provide separation. The controller had observed the altitude read out of MAPLE 32 to be FL186 and knew that VH-TQR had left FL200 on descent. VH-TQR reached FL187 prior to maintaining FL190.

The aircraft came within 6.3nm and 100ft of each other. As the radar separation standard is 5nm, no breakdown in separation occurred.

Significant Factors

1. The Air Defence Controller did not comply with the Air Traffic Control instruction received.

2. The time taken for the Senior Controller to co-ordinate with the Air Defence Controller placed the separation standard in jeopardy.

1. FACTUAL INFORMATION

At the time of the incident, both aircraft were operating in visual meteorological conditions under instrument flight rules (IFR) and proceeding on tracks that crossed near Mendooran. Both aircraft were operating at a correct hemispherical level of 9,000 ft in non-controlled airspace managed by the Sydney flight service centre (FSC). The Beech B58 pilot had not reported maintaining his cruising altitude. Prior to the occurrence each pilot had been unaware of the presence of the other aircraft. The pilot of the Cessna C402 sighted the Beech B58 just prior to the crossing of their respective flight paths. The Cessna pilot estimated that there was approximately 500 m horizontal separation as he passed behind the Beech B58. The required traffic information service had not been provided by the responsible flight information sector (FIS), which was FIS 1.

The Sydney FSC is managed by a senior area manager who has two teams, northern and southern, working the various domestic FIS sectors, identified as FIS 1 to 6, and the international sectors, identified as FIS INT 1 and 2. Each team has a team leader responsible for the operation of their respective teams during the shift.

All face-to-face pilot briefing facilities were terminated at midnight on the previous evening, 30 June 1992.

Briefings were then required to be obtained via manual or automated systems consolidated to Brisbane or

Melbourne regional briefing offices (RBOs). Aircrew could obtain operational information and submit flight plans through the relevant RBO.

One important element of the consolidated RBO program, the automated meteorological and Notice to Airmen (NOTAM) facsimile briefing (AVFAX) system, operates only from Brisbane and provides the service for the whole of Australia. On the morning of the incident, two unforeseen technical problems arose that resulted in a disruption to the system. Firstly, a software problem in the AVFAX system resulted in it not being able to cope with the extra demand on its services. Its failure left many pilots without the required pre-flight briefing information. These pilots then resorted to the only apparent avenue left to them, they telephoned the RBOs.

Secondly, contracts had been negotiated to provide an Australia-wide 008 telephone switching network. The switching was intended to divide expected calls between the two RBOs in a predetermined manner. However, the switching network was not completed until approximately midday on the day of the incident. This resulted in the Brisbane RBO having to accept more calls than the system had been designed to accept.

Subsequently, many pilots used the FIS flightwatch service to obtain briefing material that they would normally have obtained via the automated briefing systems. This placed an abnormal demand on the flightwatch service and directly contributed to increased workload for FIS operators.

The published frequency for the FIS flightwatch service in Sydney terminates at the FIS 2 workstation, adjacent to FIS 1. Both operators have shared access to a terminal of the flight information service on request (FISOR) computer system. FISOR is reported to be slow to respond to operator's commands and only one FIS operator can access information at one time. This leads to delays in providing the information to FIS operators and pilots. This incident occurred during such an occasion.

Prior to and at the time of the incident, the northern team leader was actively assisting the FIS 2 operator to process the exceptionally high level of demand on flightwatch. All other sectors were staffed in the normal manner. One FIS-rated officer was having a short break in the adjoining amenities room.

The FIS 1 officer was also under a heavier than normal air traffic workload. This was caused by a combination of factors including numerous aircraft using the FIS 1 frequency for the flightwatch service to obtain and update operational information such as meteorological forecasts and NOTAMs. One particular aircraft had made repeated requests for weather information whilst en route to Lord Howe and Norfolk Islands. The required information was not readily available to the FIS 1 operator and required special handling at a time when FIS 1's traffic and workload were increasing.

Previous pilot complaints had been received regarding slow responses to FIS flightwatch requests. Sydney FSC management had therefore issued a staff memo urging FIS operators to respond to flightwatch requests in a more timely manner. Consequently, on the morning of this incident, the workload was very high, and supervisors were fully occupied assisting all FIS sectors to cope with the operational demands.

The FIS officer concerned was performing only his second shift on the newly consolidated sector and his responsibilities involved airspace with which he was not totally familiar. In addition, he was using communication facilities with unfamiliar coverages and code groups for flight progress strip (FPS) notations. The map to which he needed to frequently refer was cluttered and locations were not easily readable. Because of this he was unable to find the actual geographic locations of many of the position reporting waypoints in the limited scan time available.

Additionally, the Sydney FSC had previously moved from the conventional single stacked FPS display to a new multiple stack, geographic, FPS display.

Standard operating procedures for the geographic FPS display required that the FIS operator check for traffic conflictions before moving any FPSs into a new bay. However, the geographic display was considerably more demanding than the former single-stack display. The stack display presented all active FPSs under one bay designator while the geographic display presented numerous bays of FPSs. The geographic display was laid out with the required bay designators so as to provide a representation of the sectors airspace, with the top of the display representing north and the left-hand side representing west.

The geographic display, while basically sound, requires the FIS operator to visually scan a larger display area than the stacked display. Additional FIS operator estimates for en-route abeam positions, associated FPS entries, as well as inter- and intra-FPS bay movements, were also required. Not all of the operational information which determines the FPS placements within the FPS bays is notated in the same prominent positions on the FPS.

The FIS 1 operator indicated that the FPS notations also served as a memory jogger to assess traffic conflicts, frequency transfers and next actions due. In this incident, the FIS 1 operator should have estimated an abeam Dubbo time for notation of the Cessna C402s FPS. That FPS should then have been placed into the same bay as the Beech B58 i.e. Mendooran. The FIS 1 operator believed that, as he had not calculated and notated the abeam Dubbo information on the Cessna C402 FPS, he must have moved that FPS across two bays and placed it directly into the bay above Mendooran. He had also overlooked the calculation, FPS notation and execution of a frequency transfer for the Cessna C402. These actions may have prompted him to believe that the Cessna C402 FPS was in fact in the wrong bay.

A further prompt that the aircraft were operating at the same altitudes could have been provided had the pilot of the Beech B58 reported maintaining 9,000 ft. This would have occurred prior to the Mendooran waypoint and required the FIS 1 operator to notate that FPS. The FIS 1 operator would probably have then rescanned the geographic display and perhaps detected that the Cessna C402 and Beech B58 were in conflict.

On 25 June 1992, a few days prior to this incident, Sydney FSC had completed a stage of consolidation and resectorisation which incorporated the Dubbo airspace responsibilities into the FIS 1 sector. Additional radio-communication facilities and frequency coverage were terminated at FIS 1.

The FIS 1 operator stated that this was his second shift on the consolidated FIS 1 sector and that he was not totally familiar with the site-specific communications coverage or geography for the new airspace. He also reported that he had found the workstations overhead map display did not readily assist in locating aircraft flight-planned tracks and waypoints during high workload situations.

Prior to Sydney FSC absorbing the Dubbo airspace, training staff from Sydney were sent to Dubbo flight service unit (FSU) to become familiar with the operation of that airspace and construct a training package. However, the training package failed to indicate to FIS operators those locations and/or routes where Dubbo FIS officers had found recurring potential conflictions.

2. ANALYSIS

This occurrence stemmed from a series of events under high workload conditions where the FIS 1 officer commenced load shedding by truncating standard operating procedures. This overload environment led to his failure to detect a basic traffic confliction between two IFR aircraft.

The closing of face-to-face briefing facilities meant that many pilots had not used the new remote briefing facilities for the first time on the morning of 1 July 1992. They then overloaded the RBO facilities either by not fully understanding the method of use or by not organising the extent of information required i.e. they asked the system facilities to provide them with more information than they may have actually needed.

The failure of the automated briefing systems left pilots waiting to depart without sufficient operational information. Many of them departed without briefing and used the FIS flightwatch service to obtain their requirements when airborne.

Flightwatch is primarily designed to provide updates to briefings already received. It was not intended to provide the volume of information that was being requested on the morning of 1 July 1992. Consequently, the Sydney FIS operators were very busy with non-routine requests.

The high workload and diverse spread of next action due information on the relevant FPSs, combined with an unfamiliar geographic display, actively contributed to the loss of situation awareness and the failure to detect the traffic confliction.

The situation was probably further exacerbated by this officer's long experience (approximately 19 years) with the single stack display system before conversion to the new multi-stack geographic display. He had used the multi-stack geographic display for a few months previously, but only for Sydney FIS airspace with which he was more familiar.

On the day of the incident, he was using the geographic display in a totally new airspace environment. He had received approximately 8 hours of simulator training for the consolidated FIS 1 sector. While this may have been appropriate for normal traffic levels and demands, the simulator training could not possibly have anticipated the exposure to the high workload situation encountered on the morning of the incident.

The effects of the FPS geographic display, high workload, cluttered overhead map displays and the responsibility for additional airspace, had to be assimilated by the officer in a short time. This resulted in not being able to maintain the level of traffic and situation awareness needed to perform all the functions required at that time.

Unfamiliarity with the peculiarities of the Dubbo airspace and geography and the new FPS display presentation in such high workload situations, probably contributed to the operator reverting to a previously learnt behaviour and procedures applicable to a stack display. As a result of attempting to 'keep the picture', the relevant FPSs for the Cessna C402 were placed into the incorrect FPS bay without appropriate notations and recognition of the crossing of aircraft flight paths.

3. CONCLUSIONS

3.1 Findings

1. Numerous aircraft operators were not conversant with the remote briefing arrangements following the closure of face-to-face briefing facilities.
2. AVFAX failed to handle the increased demand for services imposed on the first operational day following the cessation of face-to-face briefing facilities.
3. The national 008 phone number automatic switching program had not been completed.
4. Many pilots departed without being able to obtain adequate briefing information.
5. Many pilots used the FIS flightwatch service for in-flight briefings because they had been unable to obtain them from the RBOs.
6. The interrogation and response processes of the FISOR terminal was slow.
7. The FISOR terminal was shared by two FIS sectors.
8. Management had issued a memo urging FIS officers to expedite processing of pilot requests for FIS flightwatch service.
9. The Beech B58 pilot did not report reaching his cruising level.
10. The FIS 1 operator experienced a substantial increase in workload.
11. A new FPS geographic display system was in use.
12. The FIS 1 operator was not totally familiar with working the former Dubbo FIS airspace.
13. The FIS 1 workstation overhead map display was cluttered and unsuitable for use under the circumstances current at the time of the incident.
14. The transfer of local operational knowledge from Dubbo FSU to Sydney FSC did not incorporate known areas of potential traffic conflict or potential frequent confliction.
15. The FIS 1 operator omitted some documented FPS procedures and practices which removed a number of safety net indicators.

3.2 Significant Factors

1. The FIS flightwatch service was used as a briefing service when AVFAX was unable to handle the load placed upon it.
2. The FIS 1 operator was exposed to a substantial increase in workload at a time when his experience with the geographic display and his knowledge of the airspace were insufficient to manage that increase.
3. Some operationally pertinent flight progress strip notations were omitted while others were recorded in less conspicuous and non-sequential areas of the relevant flight progress strips.
4. The training program for FIS 1 operators did not adequately address known points of frequent confliction.

SAFETY ACTIONS

4.1 As a result of this investigation, the following safety actions were suggested to the local management of the Civil Aviation Authority at the Sydney Flight Service Centre:

1. whilst being conscious of the industry perceptions of service, remind its local flight service officers of the necessity to give priority to traffic conflicts first and FIS flightwatch second;
2. provide a standardised and simplified overhead map display at the FIS 1 workstation. The overhead map display should be similar to that provided at the other operational workstations and simulator;
3. amend the local operating instructions for FIS 1 to include the peculiarities of the Dubbo airspace, geography and known traffic confliction locations; and
4. amend the manual of Air Traffic Services to ensure that FIS operators estimates of abeam positions and frequency change requirements are recorded in a more prominent and sequential area of the flight progress strip where FIS geographic display systems are in use.

The pilot reported that prior to landing all landing gear system indications were normal, with all legs of the gear indicated down. After touchdown the left wing slowly lowered, and the pilot was unable to prevent the wingtip and propeller from contacting the ground. The aircraft then veered to the left off the runway with the left landing gear collapsed.

Subsequent examination found a torsional overload failure of the left maingear leg torque tube originating from cracks near the fork bolt boss. The torque tube cracking is thought to be caused by repeated overloading of the torque tube assembly due to inadequate lubrication, during routine maintenance, of the retraction linkages. This is a known problem and is addressed in Airworthiness Advisory Circular (AAC) 160-4 of February 1985.

The subject torque tube was of an old design without the later modification introducing the reinforcing gusset.

Section 21 (2) of the Transport Safety Investigation Act 2003 (TSI Act) empowers the Australian Transport Safety Bureau (ATSB) to discontinue an investigation into a transport safety matter at any time. Section 21 (3) of the TSI Act requires the ATSB to publish a statement setting out the reasons for discontinuing an investigation.

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On 6 July, 2015 the ATSB commenced an investigation into a reported near collision involving an Aeroprakt 22LS, registered VH-EVQ and a Piper PA28, registered VH-NRZ at Bankstown Airport, New South Wales on 28 June 2015.

As per procedure, the pilot of the PA28 called Bankstown Tower when at Prospect Reservoir, for a clearance to enter the control zone. ATC  issued a clearance for the PA28 to join downwind for runway 29 R and maintain 1,500 ft. Shortly after, ATC issued a traffic alert to the pilot of PA28. As the PA28 was tracking in a southerly direction from Prospect, making it in potential conflict with an airborne Aeroprakt 22LS. The Aeroprakt 22LS was climbing after the pilot had been cleared for a departure from runway 29R. The pilot of the Aeroprakt 22LS manoeuvred to the left to increase separation with the PA28.

The ATSB reviewed the recorded air traffic control data. The data indicated that the separation distance between the two aircraft was not as close as first reported, meaning that a near collision did not occur. The ATSB did not identify any systemic issues that contributed to the incident and assessed that no safety issues would be identified by continuing the investigation. On that basis, the ATSB has decided to discontinue the investigation.