The ATSB was advised of two aircraft proximity events at Ballarat Airport, Victoria on 4 August 2012, which occurred within a short period of time. Both incidents were witnessed by an observer on the ground.
The first incident involved VH-VSD and VH-VTA, who were observed passing in close proximity overhead the airport, on reciprocal headings.
About 20 minutes later, a second incident occurred overhead, when VH-PKH was observed to pass below VH-VTJ. Airservices Australia surveillance data indicated that the distance between the aircraft reduced to 0.1 NM laterally and 100 ft vertically.
These incidents highlight the importance of pilots effectively broadcasting and actively listen to the radio, and maintaining a vigilant lookout at all times, to enhance traffic and situation awareness. This is particularly important when operating in a high traffic density environment.