Narrative:

Location: intersection left, runway 25L approach. We were cleared for the visual approach to runway 25L. Approaching intersection left on GS, we received a 'descend' RA and complied with it. Switching from socal to tower, I reported intersection left and that we were following an RA. Tower reported traffic on a visual to runway 25R which had pulled up wingtip to wingtip. I believe approach had cleared this aircraft to pass above and behind us, the first officer first visually acquired the aircraft above/behind and to the right, and felt it was within 500 ft. No near midair collision was filed with the tower due to timeliness and frequency congestion. After landing, I called the lax tower supervisor and socal supervisor to discuss the event and basically failed to receive a satisfactory explanation.

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Original NASA ASRS Text

Title: A POSSIBLE SYS ERROR RESULTS IN AN NMAC WHEN APCH CTL CLRS ANOTHER ACR ACFT TO CROSS OVER AND BEHIND A B737 ON APCH TO RWY 25L AT LAX, CA.

Narrative: LOCATION: INTXN L, RWY 25L APCH. WE WERE CLRED FOR THE VISUAL APCH TO RWY 25L. APCHING INTXN L ON GS, WE RECEIVED A 'DSND' RA AND COMPLIED WITH IT. SWITCHING FROM SOCAL TO TWR, I RPTED INTXN L AND THAT WE WERE FOLLOWING AN RA. TWR RPTED TFC ON A VISUAL TO RWY 25R WHICH HAD PULLED UP WINGTIP TO WINGTIP. I BELIEVE APCH HAD CLRED THIS ACFT TO PASS ABOVE AND BEHIND US, THE FO FIRST VISUALLY ACQUIRED THE ACFT ABOVE/BEHIND AND TO THE R, AND FELT IT WAS WITHIN 500 FT. NO NMAC WAS FILED WITH THE TWR DUE TO TIMELINESS AND FREQ CONGESTION. AFTER LNDG, I CALLED THE LAX TWR SUPVR AND SOCAL SUPVR TO DISCUSS THE EVENT AND BASICALLY FAILED TO RECEIVE A SATISFACTORY EXPLANATION.

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.