Narrative:

Approaching the san mateo bridge on the sfo FMS runway 28R approach, we were descending in clear WX toward 1800 ft MSL. TCASII displayed a proximate target at our 1 O'clock position, at a distance approximately at the location of the bridge. We scanned and visually acquired a GA aircraft flying from our right to left at the same time that our TCASII generated an RA 'monitor vertical speed.' we stopped our descent at 2300 ft MSL in compliance with the RA and watched the GA aircraft pass directly beneath us. We were precisely on the sfo 095 degree radial just outside the bridge. TCASII showed the aircraft to be 400 ft below our altitude. We reported these events to norcal approach control as they occurred. They had never pointed out the aircraft to us. The controller responded that they would take care of it. Had we not had TCASII, and had we then continued on a normal descent toward the published crossing altitude of 1800 ft MSL at the bridge and not visually acquired and subsequently maneuvered to avoid that aircraft, we would have collided. No abrupt maneuvering was ever required during this event, and we continued to a normal stabilized approach and landing.

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Original NASA ASRS Text

Title: A319 CREW AND A GA ACFT HAD AN NMAC OVER THE SAN MATEO BRIDGE IN SFO CLASS B.

Narrative: APCHING THE SAN MATEO BRIDGE ON THE SFO FMS RWY 28R APCH, WE WERE DSNDING IN CLR WX TOWARD 1800 FT MSL. TCASII DISPLAYED A PROXIMATE TARGET AT OUR 1 O'CLOCK POS, AT A DISTANCE APPROX AT THE LOCATION OF THE BRIDGE. WE SCANNED AND VISUALLY ACQUIRED A GA ACFT FLYING FROM OUR R TO L AT THE SAME TIME THAT OUR TCASII GENERATED AN RA 'MONITOR VERT SPD.' WE STOPPED OUR DSCNT AT 2300 FT MSL IN COMPLIANCE WITH THE RA AND WATCHED THE GA ACFT PASS DIRECTLY BENEATH US. WE WERE PRECISELY ON THE SFO 095 DEG RADIAL JUST OUTSIDE THE BRIDGE. TCASII SHOWED THE ACFT TO BE 400 FT BELOW OUR ALT. WE RPTED THESE EVENTS TO NORCAL APCH CTL AS THEY OCCURRED. THEY HAD NEVER POINTED OUT THE ACFT TO US. THE CTLR RESPONDED THAT THEY WOULD TAKE CARE OF IT. HAD WE NOT HAD TCASII, AND HAD WE THEN CONTINUED ON A NORMAL DSCNT TOWARD THE PUBLISHED XING ALT OF 1800 FT MSL AT THE BRIDGE AND NOT VISUALLY ACQUIRED AND SUBSEQUENTLY MANEUVERED TO AVOID THAT ACFT, WE WOULD HAVE COLLIDED. NO ABRUPT MANEUVERING WAS EVER REQUIRED DURING THIS EVENT, AND WE CONTINUED TO A NORMAL STABILIZED APCH AND LNDG.

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.