Bandit,
As a far as the military it leaves very small margin for error under our CTA,with the high ground.Thats why if they have a low level abort,the first we know about it is they are well in CAS.Things happen quickly at 500kts.
Thats the joys of being surrounded by class G,and a low level playground.
As far your other point,if they are not squawking,or mode A only,then the controller has no way of telling that a/c is in or out of CTA.We therefore ASSUME that the target is out,unless we have information that it's lost etc.
I have seen the military infringe the CTA,then realise what they've done,and switch off the transponder.They then get out of the CTA quick,then switch it on again.:= The only conflict alert I've used worked on mode c readouts,and also a rate of closure.However at ABZ we don't have conflict alert on the radar at all.Got to keep your eyes peeled all the time with mil under the CTA.

throw_a_dyce: fascinating insight- cheers:ok:.

But pls forgive me if I appear like a stuck record here..but I find it very hard to believe a controller would allow two radar returns to merge purely on the assumption the non-squawking/modeA aircraft is not infringing. Would you just sit there with fingers crossed under the desk hoping that the unidentified a/c is not at the same level? (I take it a verbal traffic advisory would be issued to the controlled traffic at the least?).

Bandit - sorry to disappoint but we don't even cross our fingers.

Jeez!!:\
Right well, I'll insist on a window seat and keep my scan going on the holiday jets in future!!:eek:

On a related topic - there are certain aerdromes that fall just within the London CTR. Obviously there are rules governing joining, circuits, departure etc, so as not to conflict with London inbound/outbound traffic. What therefore is your take on transponder use in the circuit or in vicinity of the aerodrome?

Some aerodromes advocate transponder on standby in the circuit, but mode C when departing. Would it not be a lot easier at these fields if everybody squawked charlie all of the time? Surely there is enough seperation at these places as not to invoke a TA, and wouldn't it make the picture clearer to controllers (instead of just getting primary returns?)

I understand there was also some consideration to use a generic circuit squawk code, which would sure help at these fields (again with "c") Whatever happend to that?