On 6 June 2013, the pilot in command and student pilot of a Cessna 172 aircraft, registered VH‑WYG (WYG), were conducting a training navigational flight from Bankstown to Goulburn, New South Wales. At 1325 Eastern Standard Time, WYG was cleared to take off on runway 29 Right (29R). Immediately after this, a Cessna 185 aircraft, registered VH‑OZX (OZX), was cleared to line up on runway 29 Centre (29C). There was also active circuit traffic on runway 29 Left (29L).
The pilot of OZX was conducting a ferry flight from Bankstown to Moruya and was cleared for take-off on 29C at 1326, just as WYG became airborne on runway 29R. Thirty seconds after this, OZX was given WYG as traffic.
As OZX climbed, the pilot lost sight of WYG. When the tower controller asked whether he still had the Cessna 172 in sight, the pilot of OZX replied in the negative and commenced looking for it to his right. In looking right, the pilot believed he may have rolled the aircraft to the right. OZX crossed over and above WYG, which was maintaining a track slightly to the north of the extended centreline of runway 29R.
The pilot of OZX reported that he had already reached the departure altitude of 1,000 ft crossing the upwind threshold prior to losing sight of WYG. WYG appeared below him and to his left.
WYG was climbing through about 700 to 800 ft above ground level when the PIC sighted OZX above the right wing. He estimated that OZX was then about 30 ft above WYG and 15 m to his right.
In Class D airspace, the onus is on the pilots of visual flight rules (VFR) aircraft to maintain their own separation. It is important to keep other aircraft in sight at all times, irrespective of the aircraft performance.