The Adelaide Flight Data Officer was under training but he prepared the strip for VH-TJD unsupervised. Due in part to the location of the strips and the pressure of attempting "to do a good job" the officer selected an Alice Springs to Sydney strip by mistake. This was passed to the controller. When the aircraft taxied at Alice Springs it was issued with a clearance by the Alice Springs Tower. Alice Springs then informed the Adelaide controller that the aircraft was taxiing for Adelaide and gave the cleared route and level. The Adelaide controller was busy at the time but he read back the cleared level. This is an acknowledgement to the Alice Springs controller that he had understood the complete communication. The Adelaide controller did not hear the destination as Adelaide and seeing the strip assumed the aircraft was tracking to Sydney. Twenty one minutes after departing Alice Springs the aircraft was instructed by one Adelaide controller to call another Adelaide controller at position Kalug on the Sydney route. The aircraft captain queried the instruction and confirmed the aircraft was tracking to Adelaide. The pilot was then instructed to descend the aircraft to Flight Level 330 to remain clear of opposite direction traffic. On 12 April 1990 Adelaide Air Traffic Control issued Aeronautical Information Circular (AIC) 8/90 titled "Co-ordination of Clearances Between Alice Springs and Adelaide". This AIC requires Alice Control to include in its advice to Adelaide Control the first position report. Adelaide Control is required to read back that position while Alice Springs ensures the read back is correct. The same procedure is required both on taxi and departure.