Narrative:

I was the south approach controller running staggered ILS's to runway 11R at msp, aircraft #1 was on final 14 mi out with traffic 3/4 of a mi ahead on the parallel localizer at 1000 ft below. I advised aircraft #1 that I was taking him off the final for additional spacing with the aircraft ahead on the parallel localizer. I then turned him to a 170 degree heading and instructed him to maintain 5000 ft. I talked to another aircraft and then returned to aircraft #1 and instructed him to turn left heading 080 degrees and intercept the runway 11R localizer. I then talked with another couple of aircraft and coordinated with the runway 11L controller to descend my aircraft #1 to 4000 ft. I then instructed aircraft #1 to maintain 4000 ft. I made another transmission and then realized aircraft #1 was still sbound on a 170 degree heading descending through 4500 ft converging with a B757, aircraft #2, on downwind at 4000 ft. I turned aircraft #2 left to 250 degrees, and then turned aircraft #1 left immediately to a 090 degree heading and issued traffic, I then turned aircraft #2 further left and issued a traffic alert. He then responded saying he was in a TCASII descent. Closest point of approach was 1.5 mi and 500 ft. After reviewing the tapes, it turns out that aircraft #3 took the call for aircraft #1 when I instructed him to turn left heading 080 degrees and rejoin the localizer. Aircraft #3 was about 25 mi out about to join. All 3 aircraft were from the same company. Better attention to readbacks from myself could have prevented this, however aircraft #1 and aircraft #3 should have been more attentive.

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Original NASA ASRS Text

Title: OPERROR BTWN ACFT #1 IN DSCNT TO 4000 FT AND ACFT #2 LEVEL AT 4000 FT. RPTR HAD INSTRUCTED ACFT #1 TO TURN TO INTERCEPT THE LOC. CLRNC WAS TAKEN ACKNOWLEDGED BY ACFT #3. RPTR MISSED THE READBACK. ACFT #1 WAS ON A CONVERGING COURSE WITH ACFT #2 WHEN RPTR REALIZED IT HAD NOT TURNED. ACFT #1 WAS TURNED BUT SEPARATION WAS LOST. ACFT #2 WAS TURNED AND MADE AN EVASIVE ACTION DSCNT AFTER RECEIVING A TCASII RA.

Narrative: I WAS THE S APCH CTLR RUNNING STAGGERED ILS'S TO RWY 11R AT MSP, ACFT #1 WAS ON FINAL 14 MI OUT WITH TFC 3/4 OF A MI AHEAD ON THE PARALLEL LOC AT 1000 FT BELOW. I ADVISED ACFT #1 THAT I WAS TAKING HIM OFF THE FINAL FOR ADDITIONAL SPACING WITH THE ACFT AHEAD ON THE PARALLEL LOC. I THEN TURNED HIM TO A 170 DEG HDG AND INSTRUCTED HIM TO MAINTAIN 5000 FT. I TALKED TO ANOTHER ACFT AND THEN RETURNED TO ACFT #1 AND INSTRUCTED HIM TO TURN L HDG 080 DEGS AND INTERCEPT THE RWY 11R LOC. I THEN TALKED WITH ANOTHER COUPLE OF ACFT AND COORDINATED WITH THE RWY 11L CTLR TO DSND MY ACFT #1 TO 4000 FT. I THEN INSTRUCTED ACFT #1 TO MAINTAIN 4000 FT. I MADE ANOTHER XMISSION AND THEN REALIZED ACFT #1 WAS STILL SBOUND ON A 170 DEG HDG DSNDING THROUGH 4500 FT CONVERGING WITH A B757, ACFT #2, ON DOWNWIND AT 4000 FT. I TURNED ACFT #2 L TO 250 DEGS, AND THEN TURNED ACFT #1 L IMMEDIATELY TO A 090 DEG HDG AND ISSUED TFC, I THEN TURNED ACFT #2 FURTHER L AND ISSUED A TFC ALERT. HE THEN RESPONDED SAYING HE WAS IN A TCASII DSCNT. CLOSEST POINT OF APCH WAS 1.5 MI AND 500 FT. AFTER REVIEWING THE TAPES, IT TURNS OUT THAT ACFT #3 TOOK THE CALL FOR ACFT #1 WHEN I INSTRUCTED HIM TO TURN L HDG 080 DEGS AND REJOIN THE LOC. ACFT #3 WAS ABOUT 25 MI OUT ABOUT TO JOIN. ALL 3 ACFT WERE FROM THE SAME COMPANY. BETTER ATTN TO READBACKS FROM MYSELF COULD HAVE PREVENTED THIS, HOWEVER ACFT #1 AND ACFT #3 SHOULD HAVE BEEN MORE ATTENTIVE.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.