Loss of separation involving a McDonnell Douglas DC-10, PK-GIB and Boeing 747, JA8182, 37 km east of Taroom, Queensland, on 18 May 1993

PK-GIB was tracking from Taroom to Udiko. JA8182 was tracking from Rockhampton to Armidale. Both aircraft were cruising at flight level 370 (F370). The tracks cross at approximately 60 nautical miles (nm) east of Taroom. PK-GIB was instructed to descend to F350 and to be established at that level by 20nm east of Taroom.

Due to language problems between the controller and the Indonesian crew, the controller was later not certain whether the crew had understood the clearance to be level at F350 by 20nm (the lateral separation point) or 30nm east of Taroom. After some further discussion, the controller finally established that the aircraft had not levelled at F350 until 41nm east of Taroom thereby compromising procedural separation standards.