Narrative:

I was training on B position (arrival) for the morning rush. The a controller, vectoring for runway 3L, had GA Y inbound for dtw. Aircraft Y decided that he wanted to land det. The a controller appreqed with B controller (the trnee) for an md procedure at 5000' with aircraft Y. The md procedure is a vector across the dtw finals between the airport and the OM's, normally at 6000'. This appreq is a verbal coordination between the 2 arrival controllers, west/O any landline use. I was positioned to the right of the trnee, away from him and a position, and never heard the coordination. The next thing I knew, the C/a sounds between air carrier X and aircraft Y southeast of the airport. Air carrier X was descending out of 6000' for the downwind. Supplemental information from acn 100172: det is in the process of changing airspace and the new airspace will help eliminate this area of conflict. I think while training it should be required for both the instrument and student to acknowledge coordination not coordinated by the override. I was training and I approved a pointout and forgot about GA aircraft Y and descended air carrier X through the same altitude. Supplemental information from acn 100091: we first saw aircraft Y at about 1 mi and it passed at the nearest point of 1/2 mi. We were passing in and out of a scattered to broken layer of clouds. Aircraft Y was descending into dtw. He said he had us in sight.

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Original NASA ASRS Text

Title: LESS THAN STANDARD SEPARATION BETWEEN ACR AND CORP ACFT. OPERATIONAL ERROR. FIVE CTLR REPORTS AND ONE FLT CREW REPORT RECEIVED.

Narrative: I WAS TRNING ON B POS (ARR) FOR THE MORNING RUSH. THE A CTLR, VECTORING FOR RWY 3L, HAD GA Y INBND FOR DTW. ACFT Y DECIDED THAT HE WANTED TO LAND DET. THE A CTLR APPREQED WITH B CTLR (THE TRNEE) FOR AN MD PROC AT 5000' WITH ACFT Y. THE MD PROC IS A VECTOR ACROSS THE DTW FINALS BTWN THE ARPT AND THE OM'S, NORMALLY AT 6000'. THIS APPREQ IS A VERBAL COORD BTWN THE 2 ARR CTLRS, W/O ANY LANDLINE USE. I WAS POSITIONED TO THE RIGHT OF THE TRNEE, AWAY FROM HIM AND A POS, AND NEVER HEARD THE COORD. THE NEXT THING I KNEW, THE C/A SOUNDS BTWN ACR X AND ACFT Y SE OF THE ARPT. ACR X WAS DSNDING OUT OF 6000' FOR THE DOWNWIND. SUPPLEMENTAL INFO FROM ACN 100172: DET IS IN THE PROCESS OF CHANGING AIRSPACE AND THE NEW AIRSPACE WILL HELP ELIMINATE THIS AREA OF CONFLICT. I THINK WHILE TRNING IT SHOULD BE REQUIRED FOR BOTH THE INSTR AND STUDENT TO ACKNOWLEDGE COORD NOT COORDINATED BY THE OVERRIDE. I WAS TRNING AND I APPROVED A POINTOUT AND FORGOT ABOUT GA ACFT Y AND DSNDED ACR X THROUGH THE SAME ALT. SUPPLEMENTAL INFO FROM ACN 100091: WE FIRST SAW ACFT Y AT ABOUT 1 MI AND IT PASSED AT THE NEAREST POINT OF 1/2 MI. WE WERE PASSING IN AND OUT OF A SCATTERED TO BROKEN LAYER OF CLOUDS. ACFT Y WAS DSNDING INTO DTW. HE SAID HE HAD US IN SIGHT.

Data retrieved from NASA's ASRS site as of August 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.