Narrative:

While working final I had 2 aircraft on parallel bases. I issued traffic to the (B757) one closest to the airport when I noticed that I had 2 additional aircraft; one on downwind and one on wide base descending to the same altitude on a collision course. I asked the controller that was still working the aircraft on downwind to descend that aircraft to a lower altitude to alleviate the confliction. I then turned the aircraft (B737) approaching the final and furthest from the airport onto the localizer. Then I queried the other aircraft (B757) if he had started his turn to join the localizer. He said that he had not; but he would start it now. I asked the second aircraft (B737) if he had the first one (B757) in sight. He responded that he had a colored figure. I asked him again if he had the traffic in sight. He said yes and I instructed him to maintain visual separation from the traffic. The supervisor had me relieved; so that the tapes could be reviewed for a possible error. The operational manager reviewed the audio and video playback and thought that it was error-free. Only after further review of the data extraction were we able to see that I lost divergence separation a few seconds prior to obtaining visual separation. I am ultimately responsible for the position I am working; I also know that working scheduled overtime is a contributing factor to my fatigue.

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Original NASA ASRS Text

Title: A80 CTLR EXPERIENCED OPERROR AT APPROX 3500 WITH TWO ACFT BEING VECTORED TO FINAL; APPLIED VISUAL SEPARATION; BUT NOT IN TIME.

Narrative: WHILE WORKING FINAL I HAD 2 ACFT ON PARALLEL BASES. I ISSUED TFC TO THE (B757) ONE CLOSEST TO THE ARPT WHEN I NOTICED THAT I HAD 2 ADDITIONAL ACFT; ONE ON DOWNWIND AND ONE ON WIDE BASE DSNDING TO THE SAME ALT ON A COLLISION COURSE. I ASKED THE CTLR THAT WAS STILL WORKING THE ACFT ON DOWNWIND TO DSND THAT ACFT TO A LOWER ALT TO ALLEVIATE THE CONFLICTION. I THEN TURNED THE ACFT (B737) APCHING THE FINAL AND FURTHEST FROM THE ARPT ONTO THE LOC. THEN I QUERIED THE OTHER ACFT (B757) IF HE HAD STARTED HIS TURN TO JOIN THE LOC. HE SAID THAT HE HAD NOT; BUT HE WOULD START IT NOW. I ASKED THE SECOND ACFT (B737) IF HE HAD THE FIRST ONE (B757) IN SIGHT. HE RESPONDED THAT HE HAD A COLORED FIGURE. I ASKED HIM AGAIN IF HE HAD THE TFC IN SIGHT. HE SAID YES AND I INSTRUCTED HIM TO MAINTAIN VISUAL SEPARATION FROM THE TFC. THE SUPVR HAD ME RELIEVED; SO THAT THE TAPES COULD BE REVIEWED FOR A POSSIBLE ERROR. THE OPERATIONAL MGR REVIEWED THE AUDIO AND VIDEO PLAYBACK AND THOUGHT THAT IT WAS ERROR-FREE. ONLY AFTER FURTHER REVIEW OF THE DATA EXTRACTION WERE WE ABLE TO SEE THAT I LOST DIVERGENCE SEPARATION A FEW SECONDS PRIOR TO OBTAINING VISUAL SEPARATION. I AM ULTIMATELY RESPONSIBLE FOR THE POS I AM WORKING; I ALSO KNOW THAT WORKING SCHEDULED OVERTIME IS A CONTRIBUTING FACTOR TO MY FATIGUE.

Data retrieved from NASA's ASRS site as of January 2009 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.