Loss of separation involving a Piper PA-28-181, VH-UBM and Saab SF-340B, VH-SBA, 40 km north-east of Wagga, New South Wales, on 22 May 1995

The pilot of VH-UBM called Wagga Tower inbound at 45 miles on the 065 radial of the Wagga VOR, at 8000 feet. He was instructed to maintain 8000 feet and track inbound on the 075 radial. The assigned track was to ensure separation was maintained with VH-SBA, which was tracking outbound on the 053 radial, initially at 7000 feet.

Once VH-SBA had passed the lateral separation point for the two tracks, at 10 miles from Wagga, the aircraft was cleared to climb above the level of VH-UBM. Although separation was arranged by procedural means by Wagga Tower, VH-UBM was observed on radar by Melbourne air traffic control crossing the 050 radial from south to north. A loss of procedural separation occurred due to VH-UBM being off track to the north of the 075 radial.

The pilot of VH-UBM made an error in mentally orientating himself with respect to the Wagga VOR and turned right instead of left. In retrospect he was uncertain of how this occurred.

Significant Factors

The following factors were considered relevant to the development of the incident:

1. The pilot made an error in orientating himself with respect to the Wagga VOR.

2. The precise reason for this happening was not determined.