Factual Information

GIA829 was maintaining flight level (FL) 350 on air route G326 and was estimating the flight information region boundary at ONOXA at 0330 UTC.  This information was correctly coordinated by Brisbane sector control to Bali control.

GIA899 was maintaining FL 330 on air route A576 and had passed CURTIN at 0245 with an estimate for the boundary at ATMAP of 0347.  This information was also correctly coordinated with Bali control and included the specific indication of a non-standard flight level.

During the coordination process, Bali control advised that they could not accept GIA899 at the non-standard level (FL 330) and required that aircraft at FL 350.  Brisbane sector accepted this requirement and after checking his flight progress strips, the controller calculated that there would be 13 minutes between the two aircraft at Bali (Den Pasar).  As the required standard is 10 minutes, he then instructed the crew of GIA899 to climb to FL 350.

At 0329 the Brisbane controller was checking his flight strips and realised that the flight plan time interval for GIA899 between ATMAP and Bali was approximately 10 minutes in error and the separation between the two aircraft was in fact only 2-3 minutes at Bali.

When the flight times were corrected, it was realised that GIA899 and GIA829 were already within the zone of conflict and that a breakdown in separation standards had occurred.

The Brisbane controller immediately initiated coordination with Bali control, but it was some minutes before contact was made.  When coordination was completed the Bali controller accepted responsibility for re-establishing separation and commenced distance checks from the two aircraft.

It is not known exactly which separation standard was affected by Bali control.

Analysis

When Bali control made the request for both aircraft to be at FL 350 it was based on the previous reported positions of the aircraft and the flight planned times from those positions to Bali.  In the case of GIA899 this time interval was incorrect and contained an approximate 10 minute error.

As both Brisbane and Bali control were using the same flight plan details, it is likely that both controllers considered that a 10 minute separation standard existed.  It was only when the Brisbane controller checked his time intervals against those being commonly used by other aircraft during the period, that the error was noticed.

The computer aided strip printing system only provided a proportional breakdown of the block times notified on the flight plan.  In this case, the first block times were correct and there was no trend to alert control to any time interval error.

There was also a table of estimated time intervals provided on the control console for controller reference.  This table had several erroneous time intervals included in its data and was commonly not used by controllers.

Findings

1. The flight plan for GIA899 contained an erroneous time interval.
2. The table of estimated time intervals held at the Brisbane control console contained several errors.
3. Bali control was unable to accept GIA899 at a non-standard level (FL 330).
4. Both the Brisbane and Bali controllers had information that indicated that a 10 minute separation standard existed.
5. All coordination between Brisbane and Bali was carried out in accordance with the Letter of Agreement.
6. Brisbane control issued a clearance for GIA899 to climb to FL 350 in accordance with Balis requirements.
7. The actual separation was approximately 2- 3 minutes.
8. A breakdown in separation standards occurred.

Significant Factor

The flight plan details for GIA899 were errant, in that they contained an incorrect time interval between ATMAP and Bali.

Safety Action

As a result of the investigation, Brisbane ATS management have removed the erroneous time interval table from the console.  It has been replaced with a table of average times for each type of aircraft using particular air routes.

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

The aircraft departed Archerfield for Bankstown with 100 L of fuel, measured by dipstick. At Coffs Harbour a further 40 L of fuel was added. The pilot again dipped the tanks and determined there was a total of 100 L (50 L per tank) on board. The aircraft then flew to Scone where the pilot again dipped the tanks and estimated that 60 L (30 L per tank) remained. He assessed this was sufficient for the remaining leg to Bankstown.

After departing Scone, the pilot reported that he had to divert around thunderstorms. Later, he had difficulty communicating with Bankstown at Brooklyn Bridge and carried out three orbits whilst the problem was rectified. By then the fuel contents gauges were indicating very low quantities. The engine subsequently stopped in the Castle Hill area, some 10 km from the planned destination. The pilot contacted Bankstown Tower and reported he had run out of fuel and would carry out a forced landing. Although the aircraft was over a playing field, the pilot assessed it as unsuitable for a landing due to powerlines and elected to land in a residential street, where it collided with a power pole. The right wing was torn off, but both occupants managed to escape without injury.

Emergency rescue staff first at the scene of the accident reported only a small quantity of fuel was lost from the ruptured right-wing tank. Only unusable fuel remained in the undamaged left tank. Both fuel tank caps were locked, and the seals were in good condition. There was no evidence of any pre-existing leaks in the fuel system. Subsequently, the engine performed normally during a ground run, after the aircraft had been removed from the site, and a temporary fuel supply connected.

The pilot reported that the engine was operated for the entire duration of the flight without leaning the mixture. Subsequent fuel consumption calculations were consistent with fuel exhaustion at the time of engine stoppage.

Factual Information

An F27 Mk50 (F50) departed Sydney for Canberra from runway 34L and was being radar vectored by Departures South (DepS) for a left turn to intercept the 207-degree radial from the Sydney VHF omni-range beacon (VOR). The controller had restricted the climb of the F50 so that it was maintaining 5,000 ft.  This restriction was initiated in order to provide vertical separation from an arriving B747 that would be radar vectored from the west to make a left circuit to runway 34L.

The B747 was arriving at Sydney from Kuala Lumpur, Malaysia, and had been assigned 6,000 ft on descent in order to provide vertical separation from the F50. The crew had correctly read back the assigned level to Approach South (AppS) control who subsequently issued instructions for the B747 crew to turn their aircraft onto a downwind leg.

The radar vectors issued by DepS and AppS resulted in the two aircraft following flight paths that would cross each other approximately 10 NM south west of Sydney Airport.  As the aircraft converged, the controllers noticed that the height readouts from the two aircraft became 'garbled' (unreadable) and it was only when the aircraft had passed, and were approximately 2 NM apart, that they became readable again.  The AppS controller then observed that the height readout for the B747 showed 5,500 ft. At the same time the crew of the B747 queried their assigned altitude and were told that it was 6,000 ft.

By the time this conversation was completed, the aircraft were more than 3 NM apart and radar separation standard had been re-established.  The AppS controller then instructed the crew of the B747 to continue descent to 5,000 ft.

The crew of the B747 had been involved in making a public address announcement to the passengers as the aircraft had been passing 7,000 ft.  As a result, the attention of the crew was not totally on the altitude restriction and, as a result of high cockpit workload, the aircraft was allowed to descend below the assigned altitude.

The aircraft passed approximately 700-800 ft vertically apart, with no discernible horizontal displacement.  As the applicable standard is either 1,000 ft vertically or 3 NM horizontally, a breakdown of separation standards occurred.

Analysis

The operator's Standard Operating Procedures specified that the public address system should not normally be used below the transition altitude (10,000 ft in Australia).  The crew had been informed that the film being shown to the passengers was running late and the captain elected to wait until it had finished before making the public address announcements regarding arrival at Sydney.

Findings

1. The crew of the B747 allowed their aircraft to descend below the assigned level.
2. Both air traffic controllers acted in an appropriate manner.
3. The crew of the B747 made a public address announcement at a time that was contrary to company standard procedures.

Safety Action

As a result of the investigation the operating company reinforced its Standard Operating Procedures in respect to public address announcements below the transition altitude.

Upon arrival in the circuit, the pilot found that the windsock was wrapped around the pole. From local knowledge he chose to land on the 525m strip towards the north-west. Following touch down the aircraft did not slow down as rapidly as expected and overran the strip. The aircraft came to rest on a 30 degree slope just past the threshold.

Later the pilot said that the grass was wet, he landed slightly fast at 90 kts, there was a three to five knot tailwind, and he selected reverse thrust too late to avoid the overrun. The Cessna 208 flight manual recommends an approach speed of 78 kts under the prevailing conditions. The chart landing distance required was 397m.

The glider was being test flown after major maintenance had been completed. During lift off the pilot lost control and the aircraft cartwheeled. The pilot received minor injuries, and the glider was substantially damaged.

Investigation found that the ailerons had been connected in the reverse sense. During the maintenance, reassembly, rigging and preflight the glider had passed through four stages of inspection, all of which failed to detect the incorrect rigging of the ailerons.

It was found that 10 types of glider operated in Australia are fitted with common aileron drive gimbals that can be physically fitted to the incorrect side of the aircraft, thereby reversing the sense of the control.

Immediately after the accident the Gliding Federation of Australia issued an Operations Advice Notice advising details of the accident. The notice made the point that crossed controls had occurred before and that an Airworthiness Advice Notice had been issued in 1980 covering the subject. This notice stated, 'this incident emphasises the dangers of complacency; we have come to expect things to operate correctly and therefore assume that if something is working, it is working correctly'.

The Operations Advice Notice made three recommendations relating to the principles of assuring correct sense and the avoidance of external distraction during preflight inspections.

The Gliding Federation also issued an Airworthiness Directive requiring, on the subject gliders, gimbals for the left wing to be painted bright red and for the gimbals for the right wing to be paint bright green. This action is to be performed at the next annual inspection.

The flight was the first leg of a ferry flight from Australia to the United Kingdom. After passing Adelaide the crew were advised of a change in the weather, because of a cyclone, which meant that their planned destination required an alternate. They elected to change their destination to Broome and re-planned the flight to track via overhead Ayres Rock. Navigation for the flight was being conducted by reference to a global navigation system (GNS).

The crew did not attempt to confirm their Ayres Rock position by checking the Alice Springs navigation aids. Instead, they relied solely on the GNS readout. The GNS positions were not checked on the Ayres Rock - Broome leg because of a lack of ground-based navigation aids. Approaching Broome, as indicated by the GNS, the crew attempted to obtain a cross-check from the navigation aids at Curtin but were unable to obtain any useful information. The crew were also unable to obtain any information from the Broome navigation aids.

The pilot-in-command commenced an instrument descent into Broome using GNS information only. He became concerned after the aircraft had descended to 2,400 ft above mean sea level and the crew could not see the ground, the radio altimeter was indicating the aircraft was only 600 ft above ground level and they were unable to contact anyone using the VHF radio. The pilot-in-command declared an emergency, indicating that he was unsure of his position and that he had 30 min fuel remaining, before climbing the aircraft to 6,000 ft. During the next 45 min the crew, with the assistance of air traffic services and another aircraft, attempted to establish the aircraft's position without success. Eventually a passenger, using a portable global position system receiver which was held against a cabin window, was able to establish that the aircraft was 79 NM north of Telfer. Air traffic services activated the lights at Telfer aerodrome and the aircraft landed there with limited fuel remaining 65 min after the aircraft's original estimate for Broome.

An investigation determined that the planning and conduct of the flight was deficient in a number of areas and that these contributed to the occurrence. Some of the more significant areas were crew compliment, approval and use of global navigation systems and the continued operation of a jet aircraft at low level in a critical fuel situation.

The aircraft was certified for two pilot operation with both pilots endorsed on type. The co-pilot was not endorsed on type, he was not familiar with the aircraft's GNS equipment and had not been trained in its use.

It was considered likely that inaccurate information was inadvertently entered into the GNS after the decision to change the route and destination was made. As the pilot-in-command did not have a standard checking procedure for changes to GNS information, and the co-pilot was unfamiliar with the system, the errors went undetected.

The pilot-in-command's acceptance of GNS information only for route tracking and descent, when some ground aids were available to cross check the information, indicated a lack of understanding of the use of defences to improve the level of aviation safety and of Australian requirements for the use of GNS as the sole means of navigation.

The crew's inability to establish contact with a ground-based navigation aids and VHF radio stations after the descent was probably a function of the aircraft's altitude and distance from them. In addition, operations at low level in jet aircraft are inefficient as far as fuel usage is concerned. In remaining at low level for over 45 min the pilot-in-command exhibited a lack of understanding of communication and aircraft operational limitations.

Debris was found on the runway shortly after the aircraft had landed. Maintenance investigation found that the number 1 engine thrust reverser was damaged. The number 5, 7 and 8 blocker doors were broken, and the variable guide vane cover panel was missing. The BASI investigation was not able to determine the cause of the failure.

A solo rated pilot was undertaking a check flight with a highly experienced instructor. Operations were from the 01 strip with a 20 to 25 knot wind gusting from the northwest. While the glider was in flight a decision had been made to cease operations due to the inclement weather conditions. During the landing the sols pilot was unable to maintain directional control and the glider weathercocked.

The instructor was not able to take over and recover the situation before the glider collided with a parked glider severing one metre from its right wing.

Two aircraft, at the same level on air route A585, lost separation standards assurance when the controller did not apply the appropriate standard. The lead aircraft was a RAAF VIP Boeing 707 carrying the Australian Prime Minister. The trailing aircraft was a scheduled Qantas passenger service.

The Brisbane Sector 12 controller applied a 10-minute separation standard instead of a 15-minute Oceanic standard when he allowed the lead aircraft to climb to the same level as the trailing aircraft. Later, the controller assured Perth Sector 1 controller that the 10-minute separation standard would be monitored and a distance standard established if necessary.

The separation was reduced to eight minutes at Port Hedland when the lead aircraft, Aussy 360 arrived one minute later than ETA and QFA10 arrived one minute earlier than ETA. The controller did not establish a distance standard (20 NM on DME or 30 NM RNAV) when the aircraft entered the CTA, 120 NM north-west of Port Hedland.

The controller applied an incorrect separation standard of 10 minutes to the aircraft at DOMOM whereas the oceanic standard was 15 minutes. He also did not establish a distance standard between the two aircraft as agreed with the Perth Sector 1. The controller could not explain the omissions. However, he was on a late-night shift with little traffic under his control. He may have been in a state of low arousal and was unaware of the errors.