On 26 November 2012, a flight instructor and student flight instructor of a Piper PA-28 (Warrior) registered VH-LXH (LXH) were conducting circuits at Moorabbin Airport, Victoria. Soon after LXH had conducted a touch and go, the flight instructor and student pilot of another Warrior, registered VH-TAU (TAU), commenced circuits. ATC advised TAU that they were cleared for takeoff and to follow the ‘Cherokee’ (LXH) that was currently on the runway.
At 1528, TAU was observed commencing the turn onto crosswind, at 700 feet above mean sea level (AMSL). At that time, LXH was on mid-crosswind, maintaining 1,100 feet. A review of the radar data indicated that the turn occurred earlier than other aircraft in the circuit. The instructor of LXH also observed TAU turn onto crosswind early and continued to monitor the aircraft.
Soon after, TAU commenced the turn onto downwind. The instructor of LXH continued to monitor the location of TAU and at 1529, observed TAU pass 100 feet below. About 30 seconds later, the instructor of TAU observed LXH to the left advised ATC and asked if they were to be following that aircraft. ATC confirmed that TAU was to follow LXH and that they should widen their circuit to ensure separation.
When operating in an area of high traffic density, it is crucial that pilots utilise both alerted and unalerted see-and-avoid techniques. Also, pilots should be mindful that when the circuit area is busy, it is important to conform to the circuit pattern being employed at the time to ensure sufficient separation with preceding and following aircraft.