ATC in Scotland
 

Did I read correctly some time back that Mode a/c radars were to be discontinued in Scotland on 31 December 2011? All scottish NATS radars are now Mode S????

Don't know about elsewhere, but Edinburgh's getting Mode S functionality. This doesn't mean Mode A and C won't be picked up though! It'll continue to work as before but we will be able to interrogate mode S transponders additional information.

Glasgow is still Mode A and C ... mode S will arrive at some point. But the guys didn't know when, thats the last I heard.

Plus, I am no expert, but I thought mode S was just extra information ... so mode A and C secondary radars will still only get the Mode A and C info, not the extra stuff being broadcast from the aircraft transponder.

Not sure If I'm right, but that was my understanding of it.

If I understand it correctly (and I think I do!)

A mode S radar head looks for modes A, C & S. Until recently mode S radars have worked in combination with A/C radar heads, the sites are being replaced with MODE S only radar heads. Less equipment, less to go wrong.

And less redundancy if it does....

At Edinburgh we're ditching SSR radar heads altogether and getting Multilateration which includes Mode S, more accurate and more reliable.

Yes on 31 Dec 2011 all Mode a/c radars should have been replaced by Mode S.

extract from Cap 761 here:

The environmental benefits of using Mode S interrogators for both civil and military ATS applications are fully recognised by the NISC. Consequently, under Schedule 5 of the Air Navigation Order (ANO) 2005, the UK CAA has mandated the carriage of Mode S transponders for the majority of aircraft operating in designated airspace1. Furthermore, it is developing policy to increase equipage levels and extend Mode S airspace2. The environmental benefits will only be realised fully with widespread Mode S equipage of ground interrogators and airborne transponders. Therefore, the NISC will no longer issue approvals for ground-based (including maritime) or airborne3 IFF/SSR Mode A/C interrogators after 31 December 2011.

Thats the bit I was looking for. I think the wording that is important is that they will no longer issue approvals for mode a/c radars after 31 December 2011 so only Mode S approvals after that. So I guess it will take some time to phase out mode a/c

Tom