The two PC-21s were identified as A54-046 & A54-048 and flew as "Mayhem 11" and "Mayhem 12" respectively.
Both aircraft parked on the Northern Military Hardstand before later taxing over to the Rockhampton Airport General Aviation (GA) Apron where they were reportedly placed in one of the hangars. It seems that they have deployed to Rockhampton Airport possibly in support of Exercise Rogue Ambush 2021-2 which will reportedly see RAAF fast jets fly up to the Shoalwater Bay Training Area (SWBTA) from Williamtown and RAAF Base Amberley.
Another PC-21 of No. 4 Squadron - A54-047 "Raven 20" - was noted visiting Amberley from Williamtown also on Tuesday 30 November.
Of interest, the RAAF has acquired 49 new Pilatus PC-21 turboprop aircraft and 7 flight simulators as part of the AIR 5428 Pilot Training System project, with the PC-21 aircraft replacing the RAAF's current Pilatus PC-9/A aircraft. They are mostly based at RAAF Base East Sale in Victoria and RAAF Base Pearce in Western Australia.