I took this up recently at AOPA. Martin assures me that they have workable proposals.
But, having spent £17500 for the privilege of being able to fly my 4 ac under IFR in Class D airspace thanks to the FM immunity issue, to spend even more on Mode S when only the TMAs will get Mode S interrogators for some considerable time seems nonsensical. One thing we should do is to consider whether we need so much Class D airspace - why on earth Brize Norton and Lyneham should have it when Exeter and Humberside cope without is beyond comprehension.......
There needs to be some god
PR over this - perhaps all those flying on the Dec 17 'Century of Flight' day will make the point that they all managed to do so without Mode S......