TCASII RA CAUSES ACR MLF FLC TO STOP DSCNT.

Narrative

DSNDING INTO DFW EVERYTHING WAS NORMAL UNTIL TCASII GAVE US A TA ABOUT 10 O'CLOCK AT 7 MI; 1700 BELOW US -- WE HAD NO IDEA WHO IT MIGHT BE. THE CTLR WAS SO BUSY WE COULDN'T GET A WORD IN. TCASII GAVE US A 'REDUCE DSCNT' CUE FOLLOWED QUICKLY BY A 'CLB; CLB' RA SIGNAL JUST ABOUT THAT TIME CTR TOLD US OF VRR TFC (Y) AT THE SAME POS. WE HAD ALREADY STARTED EVASIVE ACTION; AND SO ADVISED ATC. WITHIN SECONDS; TCASII RETURNED US TO NORMAL AND WE ADVISED ATC WE COULD NOT GUARANTEE THE XING RESTRICTION AT BOIDS INTXN. ATC ACKNOWLEDGED - THEN TOLD THE VFR (Y) TFC TO EXPEDITE THEIR DSCNT IF THEY COULD SINCE THEY WERE RIGHT IN THE MIDDLE OF A BUSY ARR RTE. THE FRUSTRATING THING ABOUT THE EVENT WAS THAT THE VFR TFC WAS MONITORING THE ATC FREQ. EVIDENTLY THE CTLR WAS SO BUSY WITH ALL THE INBOUND TFC HE COULDN'T LET US KNOW SOONER ABOUT THE IMPENDING CONFLICT. HE HAD ASKED THE VFR TFC (Y) EARLIER WHEN THEY WERE GOING TO START A DSCNT; EVIDENTLY REALIZING A POTENTIAL CONFLICT WAS DEVELOPING. WE HAD AN EXPERIENCED PLT IN THE JUMPSEAT - NONE OF US SAW THE VFR TFC. PART OF THE PROBLEM WAS WE HAD HIGH SPD (ASSIGNED BY ATC) (320 KTS) AND HIGH RATE OF DSCNT (3000/FPM) BECAUSE OF DSCNT CLRNC ISSUED LATER THAN NORMAL. THINGS WERE HAPPENING VERY FAST. TCASII SAVED US FROM SERIOUS TROUBLE. THE ATC ADVISORY CAME TOO LATE (NOTE ABOVE WE HAD ALREADY STARTED EVASIVE ACTION.)