This is not new ground, but highlights the problem we have with RAS, RIS and FIS here in the uk. These services have served us well over a number of years but were written for a different age. Now that SSR is commonplace and ac are fitted with TCAS, the requirement to identify one ac and then provide that service in an unknown radar environment with primary radar blips appearing and disappearing has had its day. Now ac are fitted with SSR and can indicate to all radar units their flight rules and levels without even speaking to them an update of the service is desperately needed. The problem is compounded by commercial aircraft wanting a RAS despite the prevailing weather conditions. For example a military ac only asks for RAS as it descends or climbs through cloud, almost immediately requesting RIS when it is once again VMC, a RAS in these circumstances is a valuable tool. Equally, when the weather is poor and a military ac is on a radar recovery it will ask for RAS. The weather in such circumstances is usually to poor for other ac to fly VFR and therefore the service works. However, commercial ac will ask for RAS in gin clear weather when there are lots of VFR ac around and this is were all the problems occur.
As stated earlier under RAS the controller will pass advice necessary to maintain separation between participating ac (it doesn't say what type of participating ac just all of them) or advice necessary to maintain standard separation between unknown ac. This causes problems in the open FIR as controllers would much rather seek to co-ordinate rather than avoid as it is in the best interest of all parties.
As I work at the highland radar unit that seems to be getting all the flak, I would like to put your minds at rest on some of the issues. Commercial ac that only have advisory routes to fly on want to stick to these like glue. They are their only defence against military ac who do there best (sometimes) to avoid them. Once they come off an advisory route they are in uncharted waters and we much prefer to keep them in their comfort zone, especially as some of them are carrying up to 300 passengers. Because of this we try and co-ordinate rather than avoid and thus take them off route. If you are under a service from us, we may request that you fly not above an altitude so that we can affect co-ordination between you and the commercial ac so that 1000ft separation may be achieved. In all cases, this is a request and you are not duty bound to comply. A great deal of controller training revolves around terrain separation and instructions or request to fly not above levels. If you cannot comply with any of our requests, then say so. If for example we ask you if you could fly not above 3000ft and you can’t, you can always come back and say that you can fly not above 5000ft, in that way I can descend an ac above you to 6000ft. In all such cases you must be identified for the co-ordination to be effected, this does not mean that the controller will necessarily tell you that you are identified, this will depend on the type of service that you have asked for. All requested height restrictions should be cancelled once they are no longer valid.
It is interesting to note that the problems highlighted all revolve around civil ac both CA and GA most of the military ac are not a factor. It is also worth noting that we have received no end of thanks from the CA fraternity for the service we provide and there hasn't been a serious incident since the service started.
To re-cap the rules under which we operate don’t allow for IFR/VFR interaction only separation from all ac. These rules are both civil and military. However, I am aware there are differing interpretations. In all events, these need to be looked at again, and soon.
Requests to fly not above or not below altitudes are just that, requests. However if you say you can then please comply. If you have any burning issues then we are only a phone call away and would like to hear from you.