the new Mode S TXPs
installed in 99.9% of the air transport fleet nowadays could in fact already transmit data downwards to the controller that two aircraft are in a TCAS RA situation, making any verbal comms by the crews redundant and unnecessary..that's not the problem..
problem is, at least in Europe that Eurocontrol has not updated the groundstations here to be fully compatible with what 99,9% of the aircraft already can do..
Why?? every country still has different software and despite charging huge Nav Fess, those fees are not correctly spent by our European politicos..
so in most aircraft all that would be needed is some restrapping of on the transponder connectors, if at all.. doesn't cost a thing..
but unfortunately useless unless ATC updates their equipment