TCASII TA OR RA.

Narrative

WE WERE A COMMERCIAL AIRLINE 737 ARRIVING IN LAX TO SFO AT XX00 PM. IT WAS ALREADY DARK; BUT THE WX WAS CLR; NO SIGNIFICANT XWINDS; AND VISUAL APCHS WERE BEING CONDUCTED TO RWYS 28L AND 28R. ATC VECTORED US R TURN HDG 110 DEGS FOR THE DOWNWIND; THEN GAVE US A L 180 DEG FOR RWY 28L WHEN WE WERE ABOUT 6-8 MI OUT. WE WERE TOLD TO FOLLOW A 737 FOR RWY 28L; BUT THE SPACING WAS CLOSE: ATC TOLD US WE WERE OVERTAKING THE 737 AND ASKED FOR S-TURNS TO THE L. WE WERE ALREADY ALIGNED AS FAR L AS WE COULD GO AND STILL MAKE THE LNDG AND SINCE WE COULD SLOW FROM 180 TO 140; I TOLD ATC WE WERE DOING THAT AND WOULD S TURN IF NECESSARY. AS WE WERE DOING THIS WE NOTED ANOTHER AIRLINER AT OUR ALT AND 300 DEGS TO OUR R; APPARENTLY ALIGNED FOR RWY 28L. WE ASKED THE TWR WHICH RWY HE WAS LNDG ON. BECAUSE OF THE NOISE GENERATED BY TCASII WE COULD NOT HEAR A REPLY; BUT WE SAW THE OTHER AIRLINER BANK SHARPLY R. IT WAS HIGHLY DOUBTFUL IF THERE WAS ENOUGH ROOM FOR US TO SAFELY LAND; SO WE ELECTED AT ABOUT 400 FT TO GAR. THE GAR WAS UNEVENTFUL.