Narrative:

I was handling the radio as well as PF. The approach controller was busy, but traffic was flowing quickly. We had not been slowed and were indicating about 230 KTS. We were on base at 6000 ft and the controller had not switched us to the final controller yet, so I called the airport in sight to remind him we were still there. He then switched us to final control. Controller was quite busy also and I could not check on. We were expecting the visual approach to runway 26L and were about to fly through the localizer. I was looking out of the right window at the airport when we received a 'traffic, traffic' from the TCASII. I immediately looked around at the TCASII and then looked up to see an L1011 joining the final from the south (we were north of final). The L1011 was also at 6000 ft, so I turned off the autoplt and started a climb and turned to the right as the L1011 started a descent. As this was happening, the controller was telling us about the traffic, 'at 6000 ft,' at our altitude. We deviated altitude by about 300 ft and heading by about 20 degrees. Both controllers were very busy and the frequency was very congested. It is hard to say how close we would have come, but the TCASII was definitely beneficial in this case.

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Original NASA ASRS Text

Title: AN ACR LTT APPARENTLY OVERSHOT ITS ILS AND HAD A MINOR CONFLICT WITH AN L1011 LINING UP FOR THE PARALLEL RWY.

Narrative: I WAS HANDLING THE RADIO AS WELL AS PF. THE APCH CTLR WAS BUSY, BUT TFC WAS FLOWING QUICKLY. WE HAD NOT BEEN SLOWED AND WERE INDICATING ABOUT 230 KTS. WE WERE ON BASE AT 6000 FT AND THE CTLR HAD NOT SWITCHED US TO THE FINAL CTLR YET, SO I CALLED THE ARPT IN SIGHT TO REMIND HIM WE WERE STILL THERE. HE THEN SWITCHED US TO FINAL CTL. CTLR WAS QUITE BUSY ALSO AND I COULD NOT CHK ON. WE WERE EXPECTING THE VISUAL APCH TO RWY 26L AND WERE ABOUT TO FLY THROUGH THE LOC. I WAS LOOKING OUT OF THE R WINDOW AT THE ARPT WHEN WE RECEIVED A 'TFC, TFC' FROM THE TCASII. I IMMEDIATELY LOOKED AROUND AT THE TCASII AND THEN LOOKED UP TO SEE AN L1011 JOINING THE FINAL FROM THE S (WE WERE N OF FINAL). THE L1011 WAS ALSO AT 6000 FT, SO I TURNED OFF THE AUTOPLT AND STARTED A CLB AND TURNED TO THE R AS THE L1011 STARTED A DSCNT. AS THIS WAS HAPPENING, THE CTLR WAS TELLING US ABOUT THE TFC, 'AT 6000 FT,' AT OUR ALT. WE DEVIATED ALT BY ABOUT 300 FT AND HEADING BY ABOUT 20 DEGS. BOTH CTLRS WERE VERY BUSY AND THE FREQ WAS VERY CONGESTED. IT IS HARD TO SAY HOW CLOSE WE WOULD HAVE COME, BUT THE TCASII WAS DEFINITELY BENEFICIAL IN THIS CASE.

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.