Can anyone refute any of the following?
1. The new NATS En Route Raytheon radars (which have Mode S SSR) remain capable of detecting Mode A/C transponders
2. There are currently no terminal/approach radar systems in the UK (except Heathrow?) which have Mode S, so making Mode S mandatory in terminal and uncontrolled airspace is pointless until all those units have bought new radars or junked their SSRs and bought a feed from NATS instead.
3. Current approved ACAS systems in airliners etc can detect Mode A/C transponders just as well as Mode S transponders.
If my assumptions are correct there seems to me to be no case for requiring aircraft which have a perfectly serviceable Mode C transponder to bin it and buy a new Mode S one.
NS