Narrative:

Flight was being vectored to an approach to 21L at detroit. We were following traffic to same runway and had parallel traffic to 21R, both called out by approach control. We acknowledged and sighted both targets. At approximately 2500' approach asked us if we still had both targets. We replied we had lost the 12 O'clock traffic as it had descended into the overcast but that we still had the parallel traffic. Approach rogered that, then cleared us for the ILS 21L approach and directed us to switch to dtw tower. Upon initial call up tower asked if we still had visibility on the traffic to 21R. That aircraft had just descended into the undercast so we replied negative. Tower then directed us to climb to 3000' and turn 30 degree left, which we did.

Related reports:

Google
 

Original NASA ASRS Text

Title: ACR MLG ON INSTRUMENT APCH IS GIVEN A MISSED APCH CLRNC BY ATCT TWR LCL CTLR. ARPT MAKING PARALLEL APCH.

Narrative: FLT WAS BEING VECTORED TO AN APCH TO 21L AT DETROIT. WE WERE FOLLOWING TFC TO SAME RWY AND HAD PARALLEL TFC TO 21R, BOTH CALLED OUT BY APCH CTL. WE ACKNOWLEDGED AND SIGHTED BOTH TARGETS. AT APPROX 2500' APCH ASKED US IF WE STILL HAD BOTH TARGETS. WE REPLIED WE HAD LOST THE 12 O'CLOCK TFC AS IT HAD DESCENDED INTO THE OVCST BUT THAT WE STILL HAD THE PARALLEL TFC. APCH ROGERED THAT, THEN CLRED US FOR THE ILS 21L APCH AND DIRECTED US TO SWITCH TO DTW TWR. UPON INITIAL CALL UP TWR ASKED IF WE STILL HAD VIS ON THE TFC TO 21R. THAT ACFT HAD JUST DSNDED INTO THE UNDERCAST SO WE REPLIED NEGATIVE. TWR THEN DIRECTED US TO CLB TO 3000' AND TURN 30 DEG L, WHICH WE DID.

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.