Dick,
1/ Class D, controllers can use profile separation, basically using judgement, vs 5 min ring.
2/ Ever heard of Visual separation? You can get aircraft much closer than a radar standard.
3/ Use of geographic features can allow acft to operate much closer than a 5 mile radar standard (or even a 3 mile approach radar).
There are other flexiblilties available to D towers that the radar towers can't use. I suggest you book a visit to Hobart for a couple of hours, watch and ask for explanations of how D really works in practice.
I have visited control centres and towers in a few overseas countries. I know that tower based radar services are used in many places. I know that US has some great practices, but equally, some not so good. Personally, for example, I don't like a landing clearance being issued when the runway is occupied. That one has gone wrong a few times.
US has many differences, which makes ADSB a far better option than trying to install radars everywhere in Australia.
IFR calling VFR, climbing through traffic, see and be seen, how often has that gone wrong? How many jets have been lost due to the pilots thinking they are visually self separated from VFR traffic?
How many times have pilots on this forum been given specific traffic in close proximity, and either never seen it, or seen it at the last minute, causing a bit of a shock? Be honest! See and be seen shouldn't be relied on, especially when it involves large capacity jets, or even turbo props.
From listening to tapes, watching videos, I'd also say that non standard phraseologies, and extremely rapid speech are among other features I don't like in the US system.
What we should be doing is taking the best from everywhere, not just cloning the US.
When centre gets the approach function, you will have someone who is swapping chairs frequently, multi skilling, or combining as it is known, to save money, and little local knowledge. But, centre mandarins will get another bonus, more underlings and a bigger empire. Good luck to you.
Last edited by growahead; 10th Jul 2015 at 05:04.