Narrative:

Air carrier X was on radar vectors to dtw for runway 21L ILS. Captain (PNF) was visually following arrival aircraft in sequence for landing. First officer was manually flying aircraft. On turning base leg on vectors, captain spotted air carrier Y in the turn from the opposite side, and made the comment that air carrier Y will be going to the right side. On the final intercept vector the captain noticed the air carrier Y rolling out on same heading with our aircraft directly behind it. Captain asked dtw tower what air carrier Y who was now 2-3 mi ahead and 1300 ft below (TCASII equipment) was doing. When informed he was going to runway 21R, the captain looked down at the first officer's navigation receiver and found it tuned to runway 21R. Tower gave us a 360 degree vector for spacing and an uneventful landing on runway 21L. Factors. Captain navigation was still set to dtw VOR to give first officer DME capability. Aircraft was still in flaps 5 degree mode and rechk of navaids are made on flaps 15 degree landing check. Captain was outside observing traffic while first officer was busy inside manually flying aircraft. First officer thought we were going to the right side even though all instructions and briefs were to the left side. Corrective action. Captain navigation should have been turned to localizer frequency earlier. Would have caught going through runway 21L localizer in the turn. No mention of the air carrier Y traffic by approach only medium large transport traffic that was ahead of us. Doublechk navigation's prior to turn to intercept. While it is important to keep an eye on, what's going on outside in heavy traffic, also you must rechk your partner and inside.

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Original NASA ASRS Text

Title: ACR X MADE APCH TO WRONG RWY HAD LTSS FROM ACR Y. PLTDEV.

Narrative: ACR X WAS ON RADAR VECTORS TO DTW FOR RWY 21L ILS. CAPT (PNF) WAS VISUALLY FOLLOWING ARR ACFT IN SEQUENCE FOR LNDG. FO WAS MANUALLY FLYING ACFT. ON TURNING BASE LEG ON VECTORS, CAPT SPOTTED ACR Y IN THE TURN FROM THE OPPOSITE SIDE, AND MADE THE COMMENT THAT ACR Y WILL BE GOING TO THE R SIDE. ON THE FINAL INTERCEPT VECTOR THE CAPT NOTICED THE ACR Y ROLLING OUT ON SAME HDG WITH OUR ACFT DIRECTLY BEHIND IT. CAPT ASKED DTW TWR WHAT ACR Y WHO WAS NOW 2-3 MI AHEAD AND 1300 FT BELOW (TCASII EQUIP) WAS DOING. WHEN INFORMED HE WAS GOING TO RWY 21R, THE CAPT LOOKED DOWN AT THE FO'S NAV RECEIVER AND FOUND IT TUNED TO RWY 21R. TWR GAVE US A 360 DEG VECTOR FOR SPACING AND AN UNEVENTFUL LNDG ON RWY 21L. FACTORS. CAPT NAV WAS STILL SET TO DTW VOR TO GIVE FO DME CAPABILITY. ACFT WAS STILL IN FLAPS 5 DEG MODE AND RECHK OF NAVAIDS ARE MADE ON FLAPS 15 DEG LNDG CHK. CAPT WAS OUTSIDE OBSERVING TFC WHILE FO WAS BUSY INSIDE MANUALLY FLYING ACFT. FO THOUGHT WE WERE GOING TO THE R SIDE EVEN THOUGH ALL INSTRUCTIONS AND BRIEFS WERE TO THE L SIDE. CORRECTIVE ACTION. CAPT NAV SHOULD HAVE BEEN TURNED TO LOC FREQ EARLIER. WOULD HAVE CAUGHT GOING THROUGH RWY 21L LOC IN THE TURN. NO MENTION OF THE ACR Y TFC BY APCH ONLY MLG TFC THAT WAS AHEAD OF US. DOUBLECHK NAV'S PRIOR TO TURN TO INTERCEPT. WHILE IT IS IMPORTANT TO KEEP AN EYE ON, WHAT'S GOING ON OUTSIDE IN HVY TFC, ALSO YOU MUST RECHK YOUR PARTNER AND INSIDE.

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.