Narrative:

While level at 5000 ft on approximately 050 degree heading socal approach called out 12 O'clock traffic at 4500 ft MSL also 10 O'clock traffic was shown on TCASII at 1000 ft above us. We did not have visual contact on either target. A few seconds after controller issued 12 O'clock traffic at 4500 ft MSL our TCASII called out traffic, traffic, we saw the minus 500 trace on the scope then a red line in the descend and green band in the climb illuminated followed by a climb, climb (now minus 300 was indicated). We climbed into the green band approximately 400 ft to 5400 ft MSL and simultaneously told the controller we were climbing because of an RA. He said don't climb too much because of traffic at 6000 ft MSL. Clear of conflict was then announced and we returned to 5000 ft without further problems.

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Original NASA ASRS Text

Title: B737 HAS NMAC WITH SECOND ACFT.

Narrative: WHILE LEVEL AT 5000 FT ON APPROX 050 DEG HDG SOCAL APCH CALLED OUT 12 O'CLOCK TFC AT 4500 FT MSL ALSO 10 O'CLOCK TFC WAS SHOWN ON TCASII AT 1000 FT ABOVE US. WE DID NOT HAVE VISUAL CONTACT ON EITHER TARGET. A FEW SECONDS AFTER CTLR ISSUED 12 O'CLOCK TFC AT 4500 FT MSL OUR TCASII CALLED OUT TFC, TFC, WE SAW THE MINUS 500 TRACE ON THE SCOPE THEN A RED LINE IN THE DSND AND GREEN BAND IN THE CLB ILLUMINATED FOLLOWED BY A CLB, CLB (NOW MINUS 300 WAS INDICATED). WE CLBED INTO THE GREEN BAND APPROX 400 FT TO 5400 FT MSL AND SIMULTANEOUSLY TOLD THE CTLR WE WERE CLBING BECAUSE OF AN RA. HE SAID DON'T CLB TOO MUCH BECAUSE OF TFC AT 6000 FT MSL. CLR OF CONFLICT WAS THEN ANNOUNCED AND WE RETURNED TO 5000 FT WITHOUT FURTHER PROBS.

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.