On the evening of the incident there were six aircraft in the circuit, including two Cessna 172 aircraft (C172). Both aircraft were engaged in flying training, one a dual flight (dual C172) and the other solo (solo C172).
The pilot of the solo C172 was instructed to follow the preceding aircraft, the dual C172. As the solo C172 approached the position where the pilot normally turned from downwind onto base, the pilot looked to the left and identified what he thought were the flashing lights of the aircraft he had been instructed to follow. The turn brought the solo C172 onto a base leg inside that of the dual C172.
Approaching the position where he was to turn onto final, the pilot of the solo C172 again misidentified the aircraft he had been instructed to follow. As the pilot of the solo C172 levelled out on final, ATC queried whether he still had the aircraft he had been instructed to follow in sight. Before he could answer, the instructor pilot of the dual C172 transmitted he was descending. After acknowledging the dual C172, ATC instructed the pilot of the solo C172 to go-around.
As a result of this occurrence, the operator of the solo C172 has advised the ATSB that they have implemented a night-flying checklist to record details briefed to students on expected flight conditions and traffic densities. Also as a result of this occurrence, the operator of the dual C172 has implemented a procedure to liaise with other training organisations at Moorabbin to determine the number of aircraft programmed for night circuits.
A review conducted by the ATSB found that most of the midair collisions in Australia had occurred in the circuit area, and a high proportion of those on the final approach or the base-to-final turn. Though the review noted that there was a wide variety of contributing factors in the collisions with no dominant factors, the circumstances of a majority of the collisions were consistent with the inherent difficulties in sighting aircraft in time to avoid a collision.