POTENTIAL CONFLICT.

Narrative

UPON ARR TO MSP; WE WERE SEQUENCED IN FRONT ON AN A-320 FOR A VISUAL APCH TO RWY 11L. THE A-320 WAS CLRED THE VISUAL TO RWY 11R TO FOLLOW BEHIND US. OUR INITIAL DOWNWIND HDG WAS 300 DEGS AND WE WERE SUBSEQUENTLY TURNED TO A 220 DEG HDG FOR THE VISUAL. CLRING TO MY L; I NOTICED AN ACFT WHICH I THOUGHT WAS UNUSUAL FOR OUR POS ON BASE LEG. WE PROCEEDED WITH THE VISUAL; BUT I SENSED THE TFC WAS CONVERGING. I ASKED APCH IF THE ACFT WAS THE AIRBUS THAT HAD BEEN FOLLOWING US ON THE ARR AND AFTER A 'YES' RESPONSE; ASKED HIM HOW HE COULD NOW BE IN FRONT OF US. THE CTLR SAID THAT HE; THE A-320; WAS TO MAINTAIN VISUAL SEPARATION AND FOLLOW BEHIND US TO RWY 11R. THE A- 320 THEN REALIZED THAT HE WAS CONVERGING ON US AND STATED TO THE CTLR THAT 'THIS IS UNACCEPTABLE' AND I ECHOED THAT STATEMENT. THE A-320 THEN MADE A TURN TO HIS R AND WE CONTINUED THE VISUAL APCH WITH A SMALL TURN AND CLB TO ENSURE SEPARATION BECAUSE OF A TCASII TA. NO FURTHER COMMENTS OR DEVS WERE ENCOUNTERED AND A VISUAL APCH AND LNDG WERE ACCOMPLISHED. SUPPLEMENTAL INFO FROM ACN 276251: DURING VECTORS FOR VISUAL APCH TO RWY 11R AT MSP; WE WERE 4000 FT; 10 MI W OF ARPT HDG W (L DOWNWIND). APCH CTL STATED WE HAD TFC AT 5 MI; 4000 FT HDG S (ON BASE LEG); AT 1-2 O'CLOCK POS. WE STATED WE HAD TFC. APCH CTL STATED HE WAS TFC LNDG RWY 11L AND WE WOULD FOLLOW HIM TO THE R AND TO MAINTAIN VISUAL SEPARATION. WE ROGERED THAT. APCH CTL THEN TOLD THE TFC THAT WAS ON A CONVERGING FLT PATH WITH US THAT HE HAD TFC (US). HE STATED THEY HAD US VISUALLY. APCH CTL STATED HE HAS YOU IN SIGHT MAINTAINING VISUAL SEPARATION; CLRED FOR THE VISUAL APCH RWY 11L. ACR X SAID; 'WHAT ABOUT THAT TFC;' AT WHICH POINT WE HAD TO TAKE EVASIVE ACTION AND ALMOST AS SOON AS WE STARTED; WE RECEIVED A TCASII RA TO MONITOR VERT SPD FOLLOWED BY A DSND RA. ACR X ALSO TURNED AWAY. IT WAS INAPPROPRIATE FOR THE APCH CTLR TO ISSUE A VISUAL SEPARATION CLRNC WITH 2 ACFT ON A COLLISION COURSE IN SUCH CLOSE PROX. HE COULD HAVE VECTORED US 30 DEGS R AND THEN ISSUED THE VISUAL SEPARATION CLRNC. IT'S NOT NORMAL TO GET A 'MAINTAIN VISUAL SEPARATION' CLRNC AND SHORTLY THEREAFTER HAVE TO TAKE SIGNIFICANT EVASIVE ACTION.