Narrative:

I was vectoring air carrier X for the visual approach to runway 18L as the west final controller. I had coordination this with the east final controller. I cleared air carrier X for the visual approach to runway 18L. The east final controller cleared air carrier Y for a visual approach to runway 18L to follow air carrier X as air carrier Y had that aircraft in sight. Air carrier Y must have seen a different aircraft because they turned their base to intercept air carrier X. I advised the east final controller and air carrier X of air carrier Y's actions. The east final controller turned air carrier Y away from air carrier X. Closest proximity was about 1.5 mi and 100-200 ft vertical.

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Original NASA ASRS Text

Title: MEM APCH CTLR DESCRIBED INCIDENT WHEN TFC ON PARALLEL RWY DURING VISUAL APCH PROCS; STARTED TO FOLLOW WRONG ACFT; CORRECTED BY ATC.

Narrative: I WAS VECTORING ACR X FOR THE VISUAL APCH TO RWY 18L AS THE WEST FINAL CTLR. I HAD COORD THIS WITH THE E FINAL CTLR. I CLRED ACR X FOR THE VISUAL APCH TO RWY 18L. THE E FINAL CTLR CLRED ACR Y FOR A VISUAL APCH TO RWY 18L TO FOLLOW ACR X AS ACR Y HAD THAT ACFT IN SIGHT. ACR Y MUST HAVE SEEN A DIFFERENT ACFT BECAUSE THEY TURNED THEIR BASE TO INTERCEPT ACR X. I ADVISED THE E FINAL CTLR AND ACR X OF ACR Y'S ACTIONS. THE E FINAL CTLR TURNED ACR Y AWAY FROM ACR X. CLOSEST PROX WAS ABOUT 1.5 MI AND 100-200 FT VERT.

Data retrieved from NASA's ASRS site as of May 2009 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.