Narrative:

We were making ILS approachs to runway 29L/right. I had 2 aircraft inbound at 6000 MSL. Air carrier X was assigned heading 220 degrees for vector across the localizer for a left downwind. Air carrier Y was established on the localizer heading approximately 300 degrees. I was not aware of the conflict because I was coordinating a sequence for other aircraft. The departure controller alerted me to the situation. I instructed approach controller to climb air carrier X and air carrier Y immediately. It was later determined by cdr that loss of IFR separation occurred. This situation occurred because of lack of control by the 2 approach controllers and the additional coordination. The winds were 50 KTS at altitude and adjustments for this were inadequate. Supplemental information from acn 196750: air carrier X on approach to msp on the nickl 2 arrival. We were heading 210 degrees level at 6000 ft expecting runway 29R. The other aircraft was on the localizer inbound 296. We were advised that we were being vectored across the localizer and to expect a left downwind. Both of us became very alert because that just isn't done. We do right downwind for runway 29R and left downwind for runway 29L. Just before we crossed the localizer we saw traffic at 1 O'clock, 6000 ft inbound on the localizer 3-4 mi away. Then we also saw at 10 O'clock, 6000 ft inbound on the localizer about 2 mi away. We both said, 'looks like he's at our altitude.' just then, approach control said 'air carrier X climb to 7000 ft immediately.' he also told air carrier Y to descend to 5000 ft. I disconnected the autoplt, rotated, and simultaneously pushed the throttles up to climb power. In a matter of seconds we were level at 7000 ft. After we landed I called approach control on the telephone and asked what happened and how close we really were. Said he wasn't watching us close enough. He thought we would go behind the second airplane and that we were 'about' 3 mi apart. I think we were closer.

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Original NASA ASRS Text

Title: ACR X HAD LESS THAN STANDARD RADAR SEPARATION FROM ACR Y. SYS ERROR.

Narrative: WE WERE MAKING ILS APCHS TO RWY 29L/R. I HAD 2 ACFT INBOUND AT 6000 MSL. ACR X WAS ASSIGNED HDG 220 DEGS FOR VECTOR ACROSS THE LOC FOR A L DOWNWIND. ACR Y WAS ESTABLISHED ON THE LOC HDG APPROX 300 DEGS. I WAS NOT AWARE OF THE CONFLICT BECAUSE I WAS COORDINATING A SEQUENCE FOR OTHER ACFT. THE DEP CTLR ALERTED ME TO THE SITUATION. I INSTRUCTED APCH CTLR TO CLB ACR X AND ACR Y IMMEDIATELY. IT WAS LATER DETERMINED BY CDR THAT LOSS OF IFR SEPARATION OCCURRED. THIS SITUATION OCCURRED BECAUSE OF LACK OF CTL BY THE 2 APCH CTLRS AND THE ADDITIONAL COORD. THE WINDS WERE 50 KTS AT ALT AND ADJUSTMENTS FOR THIS WERE INADEQUATE. SUPPLEMENTAL INFO FROM ACN 196750: ACR X ON APCH TO MSP ON THE NICKL 2 ARR. WE WERE HDG 210 DEGS LEVEL AT 6000 FT EXPECTING RWY 29R. THE OTHER ACFT WAS ON THE LOC INBOUND 296. WE WERE ADVISED THAT WE WERE BEING VECTORED ACROSS THE LOC AND TO EXPECT A L DOWNWIND. BOTH OF US BECAME VERY ALERT BECAUSE THAT JUST ISN'T DONE. WE DO R DOWNWIND FOR RWY 29R AND L DOWNWIND FOR RWY 29L. JUST BEFORE WE CROSSED THE LOC WE SAW TFC AT 1 O'CLOCK, 6000 FT INBOUND ON THE LOC 3-4 MI AWAY. THEN WE ALSO SAW AT 10 O'CLOCK, 6000 FT INBOUND ON THE LOC ABOUT 2 MI AWAY. WE BOTH SAID, 'LOOKS LIKE HE'S AT OUR ALT.' JUST THEN, APCH CTL SAID 'ACR X CLB TO 7000 FT IMMEDIATELY.' HE ALSO TOLD ACR Y TO DSND TO 5000 FT. I DISCONNECTED THE AUTOPLT, ROTATED, AND SIMULTANEOUSLY PUSHED THE THROTTLES UP TO CLB PWR. IN A MATTER OF SECONDS WE WERE LEVEL AT 7000 FT. AFTER WE LANDED I CALLED APCH CTL ON THE TELEPHONE AND ASKED WHAT HAPPENED AND HOW CLOSE WE REALLY WERE. SAID HE WASN'T WATCHING US CLOSE ENOUGH. HE THOUGHT WE WOULD GO BEHIND THE SECOND AIRPLANE AND THAT WE WERE 'ABOUT' 3 MI APART. I THINK WE WERE CLOSER.

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.