Originally Posted by BEagle
such airspace may also be used by pilots wishing to fly in IMC. Without any transponder they would have to rely on the increasingly rare availability of primary radar for traffic separation
Why rare? There's no decline in the number of primary radars, quite the opposite - Doncaster and Inverness about to get their own, to name only two. And one of the very few examples of an SSR-only radar station in the UK recently had its primary reinstated. MoD has always opposed SSR-only and I can't see that changing.
NS