Which “ existing system”
Do you mean the one where CASA insist that circuit calls at nonmapped airports be on the ATC area frequency.?
Or the one that most of the RAPACs wanted? That is that calls on such airports be on the 126.7 Multicom?
Jonkstor. What would be the problem with harmonising with the simple proven FAA system?
Notice how CASA did not mention in any of their paper work how that actually worked and why it could not be introduced here.