Narrative:

I was working the stadium sector (final sequencing to runways 25 at las). The wind had shifted to a strong west wind and aircraft that normally would have taken runways 19 were requesting runway 25. Within about a 10 min period, went from light to heavy and from routine to complex. 1 aircraft reported a flap problem and had to be resequenced, and another one (one of the bizjets involved in the error) was unable to follow traffic that he had been sequenced to follow visually. The aircraft had to be broken out of the sequence and put at an altitude that complied with MVA's and also missed traffic overhead. The pilot of the bizjet was unhappy with this vc and was requesting us to mark the tapes. The bizjet was assigned 5600 ft on downwind and then cleared for a visual approach following a heavy jet. By not turning him base and then clearing him, I allowed the pilot to determine when he would turn and descend. He did neither quickly and combined with the strong west wind his base leg ended up at least 2 mi further east than I needed it to be. Once I observed the jet turning base at 5600 ft and assuming that he would continue descent, I cleared another bizjet on a straight-in approach to descend from 7000 ft to 6000 ft. I issued traffic to the straight-in aircraft but he was unable to see the base leg aircraft because of the sun. When I realized that the base leg traffic was not descending, I issued a climb clearance to the straight-in traffic but not in time to avoid a loss of separation. The mistakes I made were: 1) clearing an aircraft off the downwind when I needed to fill a hole, instead of filling the hole and then clearing the aircraft. 2) descending the straight-in traffic before having visual separation.

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Original NASA ASRS Text

Title: APCH CTLR LOST REQUIRED SEPARATION BTWN 2 CPR JETS WHEN JET ON A STRAIGHT-IN HAD NOT MADE VISUAL CONTACT WITH THE JET ON BASE LET.

Narrative: I WAS WORKING THE STADIUM SECTOR (FINAL SEQUENCING TO RWYS 25 AT LAS). THE WIND HAD SHIFTED TO A STRONG W WIND AND ACFT THAT NORMALLY WOULD HAVE TAKEN RWYS 19 WERE REQUESTING RWY 25. WITHIN ABOUT A 10 MIN PERIOD, WENT FROM LIGHT TO HVY AND FROM ROUTINE TO COMPLEX. 1 ACFT RPTED A FLAP PROB AND HAD TO BE RESEQUENCED, AND ANOTHER ONE (ONE OF THE BIZJETS INVOLVED IN THE ERROR) WAS UNABLE TO FOLLOW TFC THAT HE HAD BEEN SEQUENCED TO FOLLOW VISUALLY. THE ACFT HAD TO BE BROKEN OUT OF THE SEQUENCE AND PUT AT AN ALT THAT COMPLIED WITH MVA'S AND ALSO MISSED TFC OVERHEAD. THE PLT OF THE BIZJET WAS UNHAPPY WITH THIS VC AND WAS REQUESTING US TO MARK THE TAPES. THE BIZJET WAS ASSIGNED 5600 FT ON DOWNWIND AND THEN CLRED FOR A VISUAL APCH FOLLOWING A HVY JET. BY NOT TURNING HIM BASE AND THEN CLRING HIM, I ALLOWED THE PLT TO DETERMINE WHEN HE WOULD TURN AND DSND. HE DID NEITHER QUICKLY AND COMBINED WITH THE STRONG W WIND HIS BASE LEG ENDED UP AT LEAST 2 MI FURTHER E THAN I NEEDED IT TO BE. ONCE I OBSERVED THE JET TURNING BASE AT 5600 FT AND ASSUMING THAT HE WOULD CONTINUE DSCNT, I CLRED ANOTHER BIZJET ON A STRAIGHT-IN APCH TO DSND FROM 7000 FT TO 6000 FT. I ISSUED TFC TO THE STRAIGHT-IN ACFT BUT HE WAS UNABLE TO SEE THE BASE LEG ACFT BECAUSE OF THE SUN. WHEN I REALIZED THAT THE BASE LEG TFC WAS NOT DSNDING, I ISSUED A CLB CLRNC TO THE STRAIGHT-IN TFC BUT NOT IN TIME TO AVOID A LOSS OF SEPARATION. THE MISTAKES I MADE WERE: 1) CLRING AN ACFT OFF THE DOWNWIND WHEN I NEEDED TO FILL A HOLE, INSTEAD OF FILLING THE HOLE AND THEN CLRING THE ACFT. 2) DSNDING THE STRAIGHT-IN TFC BEFORE HAVING VISUAL SEPARATION.

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.