What sort of movements/hr are we talking about at Perth for it to be so congested that people have to hold for 15min let alone 40min????
That sounds ridiculous.
If radar coverage is out to 150nm+ at levels above 10K then even a turboprop doing 300KTAS is going to be on screen for 30min prior to the airport,right????
Surely the controllers can sequence on the STARS and with vectoring and speed control to get 10-15 aircraft in line on finals into Perth without too many problems.
Hell at LAX on any given night at any time ,esp during peak you can see 5-10 aircraft in trail coming down finals on the localizer with probably min reqd separation.
Most medium size US ports will have more traffic than Perth at any given time and a combo of slot times if necessary but mainly just good ATC practices regarding sequencing will get everyone in without any holding unless maybe extremely high traffic levels AND bad wx,eg CBs occur at the same time.