VH-FCE departed Coffs Harbour for Williamtown at 1237 ESuT and was maintaining 10,000 ft with an estimate for Taree of 1307.

VH-TQQ departed Sydney for Port Macquarie at 1231 and passed over Williamtown at 1252 while cruising at FL170 with estimates for Taree of 1307 and Port Macquarie 1314. Air traffic control (ATC) cleared VH-TQQ to leave the control area on descent and at 1305 VH-TQQ reported leaving FL170 and was instructed to contact Sydney on the area frequency.

At 1306 VH-TQQ made an all stations call on area frequency and reported having left FL170 on descent to Port Macquarie. The flight service officer (FSO) notified VH-TQQ of the Area QNH and advised that there was no IFR traffic. At 1308 the FSO advised VH-TQQ that there was traffic at 10,000 ft and the crew replied they had just sighted VH-FCE while passing through that aircraft's level.

During the subsequent investigation, the crew of VH-TQQ stated that they were descending at 1700 ft/min and were approximately 1 NM east of track. While conducting a normal lookout scan, they sighted VH-FCE approximately 1 to 2 NM to their left and an estimated 2,000 ft to 3,000 ft below.  As they could maintain visual contact, they decided that no evasive action was needed. The captain stated that had he received traffic information on VH-FCE he would have levelled off above 10,000 ft until positive passing had been established.

The crew of VH-FCE stated that they were on track and over Taree when they sighted VH-TQQ descending from approximately 1,000 ft above and 2 NM left of their aircraft. They confirmed that they heard VH-TQQ make the area transmission and were looking out for the aircraft but decided it was not necessary to respond to this transmission. They also decided that as they could see the aircraft no evasive action was necessary.

The FSO's evaluation of the situation was influenced by the phraseology used by the Sector 2 controller who indicated to the FSO that VH-TQQ would call requesting traffic information on area frequency at top of descent. The FSO had sufficient information on hand to alert both aircraft. However, when VH-TQQ called at 1306 she calculated that the time of passing would occur at 1307 and that in this time period VH-TQQ would not have descended 7,000 ft. Based on this assessment the FSO chose not to pass traffic information to the two aircraft.

CONCLUSION

Significant Factors

The following factors were considered relevant to the development of the incident.

1. The FSO incorrectly assessed a traffic conflict situation and did not pass traffic information to the crews of VH-TQQ and VH-FCE.
2. The co-ordination procedures used between ATC and FS contributed to the FSO's incorrect assessment.
3. The crew of VH-FCE had prior knowledge of the presence of VH-TQQ but decided not to respond toVH-TQQ's descent call.

SAFETY ACTION

As a result of the Bureau's investigation the Civil Aviation Authority, inter alia, reviewed the phraseologies used between Air Traffic Control and Flight Service in relation to aircraft proceeding into or out of controlled airspace.

During the take-off roll all engine indications were normal. However, shortly after liftoff the pilot noted that engine RPM was decreasing. Efforts to restore power were not successful, and the pilot was committed to a forced landing on rough terrain beyond the end of the flight strip. During the landing roll the left main landing gear was dislodged, and a fuel tank was ruptured. Fire broke out and destroyed the aircraft.

The subsequent examination of the wreckage was hampered because of the extensive fire damage. The only abnormality discovered was that those spark plugs which could be removed from the engine showed signs of being exposed to an over-rich fuel/air mixture. The fire damage to the relevant engine systems prevented the reason for this condition from being positively determined.

Shogun and Pirate sections [2 X FA 18] were operating at Flight Level 310 in the Mudgee/Cowra area when VHF communications became poor and, at times, impossible. As a result, Sydney air traffic control were unable to pass traffic alerting information for the descent phase of the operation.

Subsequent communications were established during the descent and there was no breakdown in separation.

VH-HYB, on track between Mildura and Griffith, en route to Sydney, was maintaining non-standard Flight Level 380. The non-standard level was approved by air traffic control to help the aircraft avoid turbulence. UTA 147, flying on the same track in the opposite direction was maintaining Flight Level 350 but requested a climb to Flight Level 370. This request was immediately approved by air traffic control Sector 4. An adjacent controller noticed the altitude readout on UTA 147 as Flight Level 363 when both aircraft were about 10 nautical miles apart nose to nose.

He immediately called out to the Sector 4 controller who was engaged in coordination. Before the UTA 147's altitude clearance could be amended to Flight Level 360, to achieve the required 2000 feet vertical separation, the pilot of UTA 147 read back "maintaining Flight Level 370". The controller immediately attempted to pass traffic information to UTA 147 but because of language difficulties, the information was not understood before both aircraft had passed with the reduced separation of 1000 feet.

VH-NID [DHC8] had departed Sydney for Port Macquarie and was maintaining Flight Level [FL]170 and passed Williamtown at 2139 estimating Port Macquarie at 2202 hours [All times are UTC].

VH-RUI [PA31] taxied at Port Macquarie for Williamtown at 2149 hours and was passed traffic on VH-NID by Sydney Flight Service [FS]. At 2150 hours VH-NID called on area frequency and reported leaving FL150 on descent with a circuit estimate for Port Macquarie of 2159 hours. FS passed traffic on VH-RUI to VH-NID informing the crew that VH-RUI was taxiing and would climb to 6000ft.

At 2151 hours VH-RUI gave his departure call on area frequency as time 50 and climbing to 6000ft.

No further calls were made by either crew until 2157.30 hours when VH-NID advised on area frequency that he was changing to MTAF and asked Sydney to confirm the altitude of VH-RUI as 2000ft. VH-RUI advised that he was maintaining 6000ft. Interviews confirm that the incident occurred approximately one minute prior to this transmission.

Both crews agree that the occurrence was approximately 15-20nm south of Port Macquarie and the Automatic Voice Recorder [AVR] analysis, when combined with pilot reports, put the time of passing at between 2156.30 and 2157.00 hours.

The pilot of VH-RUI stated that he first saw VH-NID descending in front of him and about 300ft above, causing him to take violent evasive action.

The crew of VH-NID stated that they saw VH-RUI about 1000m to their left when approaching 7000ft and therefore had no need to limit their descent.

Both crews were given traffic information on each other in a correct and timely manner and stated that they were on track.

The weather was fine with no cloud.

On climb out of Brisbane the crew had problems with the No 2 engine bleed and at the cruising level of Flight Level 310 were unable to control the cabin pressurization. The aircraft descended rapidly to 10,000ft and returned to Brisbane. The problem was isolated to a failed duct. The aircraft was already operating on an MEL due to the No 1 airconditioning pack being unservicable. Therefore, with the failure of the No 2 pack, pressurization was unable to be maintained. The Company is assessing the need to limit departures with one airconditioning pack inoperative.

On two occasions the aircraft suffered a loss of power on take-off due to fuel starvation. The electric fuel pump was found to be inoperative and was replaced. Subsequent operations were normal.

The number 3 engine began vibrating on climb through FL340. The vibration could be felt through the airframe. The N1 was reducing and fluctuating, and the fuel flow was reducing. The engine was shut down and the aircraft returned to Sydney.

Maintenance checks found water in the engine fuel control unit. When this was drained the engine operated satisfactorily. The source of the water could not be determined.

Flight idle RPM was not attainable on No 2 engine during descent into Hobart. Maintenance action was to lubricate the power plant control system, subsequent operations were normal.

Take-off was aborted when No 1 oil quantity dropped to zero concurrent with lack of acceleration of the No 1 engine. The oil quantity gauge was found to be faulty and was replaced. Maintenance adjusted the power lever rigging and subsequent operations were normal.