VH-LHD was on a flight from Sydney to Gunnedah and had commenced descent from 10,000ft. The pilot was advised by Flight Service that there was no Instrument Flight Rules [IFR] traffic which was the correct information at that moment. Immediately after this transmission information was received by the Flight Service Officer on VH-ASO [Mooney 20J] departing Tamworth on climb to 6,000ft on a track that conflicted with VH-LHD.
The Flight Service Officer [FSO] was performing co-ordination tasks at the time and did not immediately recognise the confliction, preferring to complete these tasks before assessing the changes due to the presence of VH-LHD. As soon as the FSO realised the situation, traffic information was passed to both pilots but as these transmissions were taking place the aircraft passed with approximately 500ft vertical separation and no horizontal separation with the top aircraft VH-LHD descending.
Significant Factor
- The Flight Service Officer did not realise the implications of the departure of VH-ASO in sufficient time to alert the pilots to the conflict.
