Narrative:

I was working huf 'right' position by myself and was spacing for cvg. The sector above was extremely busy and was handing aircraft off to me late for starting their dscnts to cvg. Also I had several departures that had to be leveled off in my sector that were scheduled to climb to the sector above me. This required extra coordination and vectoring. I took a handoff on an aircraft from ZAU at FL230 on the tarne arrival. I also had a handoff from the section above on an aircraft descending to FL240 on the tarne arrival from the west. I descended the first aircraft to 17000 ft. I told the second aircraft to fly present heading, vectors for spacing. He said he was in the turn and what heading would I like. I said heading 180. I continued with the other aircraft duties. When I looked back, the second aircraft looked like he was on a 10 degree heading. I told him to fly heading 240 and asked if he got the 180 original heading. He said he did, but he had already started a left turn for the arrival before I issued the right turn to 180. I told him to make a hard right turn to the 240 degree heading. Separation was lost between the 2 aircraft.

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Original NASA ASRS Text

Title: ZID VECTORING TWO B757'S DO NOT MAINTAIN STANDARD SEPARATION BTWN ONE IN DSCNT AND THE OTHER AT LEVEL FLT.

Narrative: I WAS WORKING HUF 'R' POSITION BY MYSELF AND WAS SPACING FOR CVG. THE SECTOR ABOVE WAS EXTREMELY BUSY AND WAS HANDING ACFT OFF TO ME LATE FOR STARTING THEIR DSCNTS TO CVG. ALSO I HAD SEVERAL DEPS THAT HAD TO BE LEVELED OFF IN MY SECTOR THAT WERE SCHEDULED TO CLB TO THE SECTOR ABOVE ME. THIS REQUIRED EXTRA COORDINATION AND VECTORING. I TOOK A HANDOFF ON AN ACFT FROM ZAU AT FL230 ON THE TARNE ARR. I ALSO HAD A HANDOFF FROM THE SECTION ABOVE ON AN ACFT DSNDING TO FL240 ON THE TARNE ARRIVAL FROM THE W. I DSNDED THE FIRST ACFT TO 17000 FT. I TOLD THE SECOND ACFT TO FLY PRESENT HDG, VECTORS FOR SPACING. HE SAID HE WAS IN THE TURN AND WHAT HDG WOULD I LIKE. I SAID HDG 180. I CONTINUED WITH THE OTHER ACFT DUTIES. WHEN I LOOKED BACK, THE SECOND ACFT LOOKED LIKE HE WAS ON A 10 DEG HDG. I TOLD HIM TO FLY HDG 240 AND ASKED IF HE GOT THE 180 ORIGINAL HDG. HE SAID HE DID, BUT HE HAD ALREADY STARTED A L TURN FOR THE ARR BEFORE I ISSUED THE R TURN TO 180. I TOLD HIM TO MAKE A HARD R TURN TO THE 240 DEG HDG. SEPARATION WAS LOST BETWEEN THE 2 ACFT.

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.