Narrative:

I was working the west arrival position using visual approaches on three simultaneous runways. I was the south runway (28). It was a little difficult to get visuals; which is what I had to run for the operation; because of lower ceilings. As long as the aircraft were slowed down I could get them down enough to see the field without problems. I was being fed by another controller. I had to stay in tight and get low to get the field. I asked the feeder position to slow them down when I noticed he had several he was feeding me; and if he didn't I wasn't going to be able to get visuals which would create/cause an error. I already had 5 in the small area I was trying to stay within to get visual approaches. I saw two heavies coming fast; and when I received the second a B747; I noticed that aircraft had a 90 KTS overtake at the same altitude as a B777; the aircraft he was following. My attention was diverted to that situation to save the error instead of the making sure my other planes were in their appropriate spots. I knew my other planes weren't in critical positions; like on base heading for another runway. I saved that error to begin with; and then caused one of my own after I became a bit flustered by it. I was trying to save spacing I needed with two larges and two heavies by keeping like aircraft together. I was trying to save altitude to do so with the aircraft I was given to do that. I; again; had to keep the aircraft fairly close to the field so they could get visual on the airport. The operation required the outboard runways to run visual approaches. I turned the A319 away from the field then back toward it to lose altitude and get the airport in sight. In turning to do so; I turned to a 300 heading and my hand off said if I stay on a 310 heading I would have divergence in case I need lower. I meant to turn to a 320 heading and said 230 heading by mistake. I do feel the disassociation in numbers came from being flustered by the previous situation I was trying to keep control of. The aircraft turned to the 230 heading and called the field in sight. I started to tell the A319 he was cleared for the visual approach; but stopped short of finishing my sentence; which would have prevented the error technically; because I thought I noticed the aircraft heading southwest instead of northwest toward ord. I asked if he was on a 310 heading. He said no; that I had given him a 230 heading. I pointed out traffic immediately and got the other aircraft in sight and told him to maintain visual separation. I cleared the A319 for the visual approach and gave him a turn toward the field. The front line supervisor was over my shoulder at this point and said have the B747 get the air carrier in sight. I am not sure if the supervisor meant the B777 or the A319; but I pointed out the A319 and the B747 called him in sight. I turned the B777 to try to save what was going on all together after that happened with the A319 and lost separation with the two heavies because the B747 passed less than four miles behind the B777 while the B777 was on base. That separation loss was less than was required. I got everyone under control again and then was relieved of position because the situation was being investigated at that point. Recommendation; I really believe if the two heavies had been slowed appropriately none of this would have happened. Regardless; next time; no matter the situation; I will do my best to stay composed and try not to transpose or disassociate numbers like I did; and clear the aircraft first. If I would have finished my sentence of; 'cleared visual'; instead of stopping; it wouldn't have been a deal; but my first thought was to keep the situation from getting worse and take corrective action as soon as I had noticed.

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Original NASA ASRS Text

Title: C90 Controller described a loss of separation event during visual approach procedures with minimal weather conditions; the reporter indicating a wrong heading assignment was the primary causal factor.

Narrative: I was working the West Arrival position using visual approaches on three simultaneous runways. I was the south Runway (28). It was a little difficult to get visuals; which is what I had to run for the operation; because of lower ceilings. As long as the aircraft were slowed down I could get them down enough to see the field without problems. I was being fed by another Controller. I had to stay in tight and get low to get the field. I asked the Feeder Position to slow them down when I noticed he had several he was feeding me; and if he didn't I wasn't going to be able to get visuals which would create/cause an error. I already had 5 in the small area I was trying to stay within to get visual approaches. I saw two heavies coming fast; and when I received the second a B747; I noticed that aircraft had a 90 KTS overtake at the same altitude as a B777; the aircraft he was following. My attention was diverted to that situation to save the error instead of the making sure my other planes were in their appropriate spots. I knew my other planes weren't in critical positions; like on base heading for another runway. I saved that error to begin with; and then caused one of my own after I became a bit flustered by it. I was trying to save spacing I needed with two larges and two heavies by keeping like aircraft together. I was trying to save altitude to do so with the aircraft I was given to do that. I; again; had to keep the aircraft fairly close to the field so they could get visual on the airport. The operation required the outboard runways to run visual approaches. I turned the A319 away from the field then back toward it to lose altitude and get the airport in sight. In turning to do so; I turned to a 300 heading and my hand off said if I stay on a 310 heading I would have divergence in case I need lower. I meant to turn to a 320 heading and said 230 heading by mistake. I do feel the disassociation in numbers came from being flustered by the previous situation I was trying to keep control of. The aircraft turned to the 230 heading and called the field in sight. I started to tell the A319 he was cleared for the visual approach; but stopped short of finishing my sentence; which would have prevented the error technically; because I thought I noticed the aircraft heading southwest instead of northwest toward ORD. I asked if he was on a 310 heading. He said no; that I had given him a 230 heading. I pointed out traffic immediately and got the other aircraft in sight and told him to maintain visual separation. I cleared the A319 for the visual approach and gave him a turn toward the field. The Front Line Supervisor was over my shoulder at this point and said have the B747 get the air carrier in sight. I am not sure if the supervisor meant the B777 or the A319; but I pointed out the A319 and the B747 called him in sight. I turned the B777 to try to save what was going on all together after that happened with the A319 and lost separation with the two heavies because the B747 passed less than four miles behind the B777 while the B777 was on base. That separation loss was less than was required. I got everyone under control again and then was relieved of position because the situation was being investigated at that point. Recommendation; I really believe if the two heavies had been slowed appropriately none of this would have happened. Regardless; next time; no matter the situation; I will do my best to stay composed and try not to transpose or disassociate numbers like I did; and clear the aircraft first. If I would have finished my sentence of; 'Cleared Visual'; instead of stopping; it wouldn't have been a deal; but my first thought was to keep the situation from getting worse and take corrective action as soon as I had noticed.

Data retrieved from NASA's ASRS site as of April 2012 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.