Avman,
I asked a question like that earlier in the thread, the simple reply is that there would be a requirement for mode-s (or in the future ADS-B).
It is obvious (and this accident is proof thereof) that ATC needs to know immediately when the TCAS commands an RA. It is also obvious that we cannot expect pilots to think about comms in an RA environment, there are just too many "more important" things happening during those moments.
There are 2 possible solutions;
The first is aircraft based, As soon as the TCAS commands an RA, it can (could) command the Transponder to automatically squawk a specific code (7400 ?) which would then indicate to the ATC that that specific aircraft is under RA navigation.
The second is based in the ATC Radar Software (maybe even as a function of STCA). The parameters used by TCAS (for RA) could be incorperated into the ATC software, so that when the RA would be commanded in the cockpit, and indication on the Radar display would show that there is a (potential) RA and indicate which 2 aircraft are involved. Bear in mind, this is simply 2 different computers that are using the same data, manipulated by the same parameters.
In addition to the above (whichever way it goes), the ATC would be mandated to take no (vertical) action until the "clear of conflict" call is made.
To repeat, It is painfully obvious that ATC needs to know when they have reached the end of their "jurisdiction", and pilot's can not be expected treat comms with any priority when they are possibly playing their last hand.
SID