Gaunty. I don't thnk DCA ever had Shrike 500S's. They had the earlier model with geared engines and the turbine G1000.
I seem to recall HC Sleigh Aviation arranged the higher MTOW weight with DCA for a specific, early (1970's?) surveillance or SAR task.
4Greens, can you post a link? All I can find on the CASA web site is the 2007 page "
Aviation Regulation Review Taskforce".