Narrative:

About 6 or 7 mi out, approach control informed us we would be switching to 25R, but we weren't real sure, so we agreed to reaffirm with tower as we were switching to tower about 5 mi out. Around 5 mi out, we switched to tower, and received TCASII RA about 2-300 ft below us. First officer was on radio confirming runway 25R while all of this was going on. I was looking outside and looked left to see a high wing commuter type level and about 100-200 ft away. He was not lit up very well and it caught me completely unaware. I had not left the 25L localizer because I wanted to confirm the switch to 25R. Approach control may have mentioned the traffic earlier, but we never saw large transport or acknowledged it. The tower chief confirmed on my telephone call that they (the tower) did not mention it to us because they assumed approach control had. The problem in my view is that approach controller should have had us visually acknowledge sight of the commuter before they switched us over to 25R, particularly with visibility of 4 mi in haze. We may have acknowledged the airport in sight but never the commuter. The commuter may have seen us as we had our landing lights on. We probably overtook the commuter and initially we were slightly above him. He may have been in a left turn as well. I doubt that I will ever accept a visual approach at lax again. Very unsafe procedure.

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Original NASA ASRS Text

Title: AN ACR LGT HAD AN NMAC WITH AN LTT DURING A VISUAL APCH THROUGH THE HAZE AT LAX.

Narrative: ABOUT 6 OR 7 MI OUT, APCH CTL INFORMED US WE WOULD BE SWITCHING TO 25R, BUT WE WEREN'T REAL SURE, SO WE AGREED TO REAFFIRM WITH TWR AS WE WERE SWITCHING TO TWR ABOUT 5 MI OUT. AROUND 5 MI OUT, WE SWITCHED TO TWR, AND RECEIVED TCASII RA ABOUT 2-300 FT BELOW US. FO WAS ON RADIO CONFIRMING RWY 25R WHILE ALL OF THIS WAS GOING ON. I WAS LOOKING OUTSIDE AND LOOKED L TO SEE A HIGH WING COMMUTER TYPE LEVEL AND ABOUT 100-200 FT AWAY. HE WAS NOT LIT UP VERY WELL AND IT CAUGHT ME COMPLETELY UNAWARE. I HAD NOT LEFT THE 25L LOC BECAUSE I WANTED TO CONFIRM THE SWITCH TO 25R. APCH CTL MAY HAVE MENTIONED THE TFC EARLIER, BUT WE NEVER SAW LGT OR ACKNOWLEDGED IT. THE TWR CHIEF CONFIRMED ON MY TELEPHONE CALL THAT THEY (THE TWR) DID NOT MENTION IT TO US BECAUSE THEY ASSUMED APCH CTL HAD. THE PROBLEM IN MY VIEW IS THAT APCH CTLR SHOULD HAVE HAD US VISUALLY ACKNOWLEDGE SIGHT OF THE COMMUTER BEFORE THEY SWITCHED US OVER TO 25R, PARTICULARLY WITH VISIBILITY OF 4 MI IN HAZE. WE MAY HAVE ACKNOWLEDGED THE ARPT IN SIGHT BUT NEVER THE COMMUTER. THE COMMUTER MAY HAVE SEEN US AS WE HAD OUR LNDG LIGHTS ON. WE PROBABLY OVERTOOK THE COMMUTER AND INITIALLY WE WERE SLIGHTLY ABOVE HIM. HE MAY HAVE BEEN IN A L TURN AS WELL. I DOUBT THAT I WILL EVER ACCEPT A VISUAL APCH AT LAX AGAIN. VERY UNSAFE PROC.

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.