Loss of separation involving a de Havilland Canada DHC-8-103, VH-NID and Piper PA-31-350, VH-RUI, 36 km south of Port Macquarie, New South Wales, on 7 September 1992

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.