The US Class D model - All Class D is approximately 5NM Air Traffic Zone (ATZ) with all IFR on SID/STAR/Inst Apch no visual approaches allowed. If you want one of those you need to cancel IFR, fly VFR, and you get to track direct to airport and join circuit. VFR get no altitude assignment just tracking instructions to enter circuit area as directed by TWR. - Unfortunately Oz still suffering hangover from the old days
Flew into several of these recently. Works a treat. Would never work in Australia, would take a fairly significant cultural change that ASA would be incapable of managing.