ACR MLG OVERSHOT TURN ON FOR RWY 18R THEN GOT A TCAS WARNING OF TFC ON VISUAL FOR 18L.

Narrative

DURING VECTORS FOR APCH TO RWY 18L; HDG 210 DEG; CTLR ASKED IF WE HAD ARPT IN SIGHT. CAPT; PNF RESPONDED YES -- CTLR CLRED ACFT FOR APCH. FO (FLYING THE ACFT) INITIATED A CLRED OF THE APCH CHKLIST. AT APPROX THE TIME THE ACFT SHOULD HAVE TURNED TO INTERCEPT FINAL A TA SOUNDED IN THE COCKPIT. THE FO LEFT THE ACFT ON THE 210 DEG HDG WHILE VISUAL SCANNING FOR THE TFC. THIS COMBINED WITH A QUARTERING TAILWIND RESULTED IN AN OVERSHOOT. ABOUT THE TIME THE CTLR MADE AN INQUIRY WHETHER WE WERE TURNING FOR THE ARPT AND DID WE HAVE IT IN SIGHT AN RA 'MONITOR VERT SPD' ANNOUNCEMENT WAS MADE (SIMULTANEOUSLY). NO DSCNT HAD BEEN COMMENCED SO IT WAS NOT NECESSARY TO LEVEL THE ACFT. THE FO HAD THE ACFT FOR 18R IN SIGHT (ACR Y) AT THIS TIME. THE CAPT DIRECTED THE FO TO MANUALLY FLY THE APCH. ACFT ON APCH FOR 18R APPARENTLY ON DIFFERENT FREQ. NO RADIO TFC WITH OTHER ACFT NOTED. FO WAS HIGHLY EXPERIENCED IN TOTAL TIME AND ON THIS ACFT. CAPT FAILED TO MONITOR CLOSELY ENOUGH WHAT SHOULD HAVE BEEN A ROUTINE VISUAL APCH. QUARTER TAILWIND CAUSED EVENTS TO HAPPEN MORE QUICKLY. CVG ROUTINELY USES TAILWIND APCHS FOR CONVENIENCE.