Narrative:

Captured localizer and GS for runway 28R abeam of 'bridges' after following the FMS bridge visual approach to samul. Had visual contact with light turboprop 3 mi ahead on runway 28L extended centerline. TCASII gave TA followed quickly by RA. Intruder may have been landing aircraft for runway 28L who overtook us but I suspect it was pop-up uncontrolled or traffic helicopter. On 10 mi range of map mode, I saw intruder at very short range (less than 1 mi) and 400 ft below us. We didn't react immediately because of the numerous false warnings I've had over the yrs while approaching sfo on those two very closely spaced runways. I fully expected to look out the left side window and see a third aircraft that probably had overtaken us while he was approaching runway 28L. When I did look out the left side and left forward windows, I could not see the intruder. By this time, TCASII showed the intruder only 300 ft below us and at very short range in our 11 O'clock position. We executed a missed approach. I am convinced TCASII saved a midair. No controller had given us any help to see or avoid the intruder. Approach had only mentioned the light turboprop on runway 28L which did not figure in this incident. I am also convinced that the practice of routinely spacing simultaneous approachs to those closely spaced runways causes far too many RA's. Such false warnings will one day result in slow or no reaction to TCASII and that will result in a midair collision. Callback conversation with reporter revealed the following information: the aircraft's forward speed was 160 KTS and reporter feels it is unlikely that another aircraft had overtaken his aircraft. There was no explanation for the warning, so the captain took evasive action and the aircraft was at 3000 ft before controller was able to acknowledge the flight crew's missed approach. Reporter states that flight operations manual gives the option for TA selection, only, when parallel approachs are in use, but that he feels this policy makes no sense. When he is in a busy terminal environment, he wants all the help he can get. Reporter believes that closely spaced parallel approachs are dangerous. In his mind the problem falls within ATC system management and not in airline operational policy or flight crew procedures.

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Original NASA ASRS Text

Title: ACR FLC EXPERIENCED AN NMAC WHILE ON AN FMS VISUAL APCH TO RWY 28R AT SFO. THE FLC FIRST RECEIVED A TA AND COULD NOT VISUALLY IDENT THE TFC. WHEN THE TCASII ISSUED AN RA THE FLC EXECUTED A MISSED APCH. RPTR DISCONTENT WAS VOICED REGARDING THE HAZARDS OF OPERATING SIMULTANEOUS PARALLEL APCHS. NMAC. FLC RESPONSE EVASIVE ACTION.

Narrative: CAPTURED LOC AND GS FOR RWY 28R ABEAM OF 'BRIDGES' AFTER FOLLOWING THE FMS BRIDGE VISUAL APCH TO SAMUL. HAD VISUAL CONTACT WITH LIGHT TURBOPROP 3 MI AHEAD ON RWY 28L EXTENDED CTRLINE. TCASII GAVE TA FOLLOWED QUICKLY BY RA. INTRUDER MAY HAVE BEEN LNDG ACFT FOR RWY 28L WHO OVERTOOK US BUT I SUSPECT IT WAS POP-UP UNCTLED OR TFC HELI. ON 10 MI RANGE OF MAP MODE, I SAW INTRUDER AT VERY SHORT RANGE (LESS THAN 1 MI) AND 400 FT BELOW US. WE DIDN'T REACT IMMEDIATELY BECAUSE OF THE NUMEROUS FALSE WARNINGS I'VE HAD OVER THE YRS WHILE APCHING SFO ON THOSE TWO VERY CLOSELY SPACED RWYS. I FULLY EXPECTED TO LOOK OUT THE L SIDE WINDOW AND SEE A THIRD ACFT THAT PROBABLY HAD OVERTAKEN US WHILE HE WAS APCHING RWY 28L. WHEN I DID LOOK OUT THE L SIDE AND L FORWARD WINDOWS, I COULD NOT SEE THE INTRUDER. BY THIS TIME, TCASII SHOWED THE INTRUDER ONLY 300 FT BELOW US AND AT VERY SHORT RANGE IN OUR 11 O'CLOCK POS. WE EXECUTED A MISSED APCH. I AM CONVINCED TCASII SAVED A MIDAIR. NO CTLR HAD GIVEN US ANY HELP TO SEE OR AVOID THE INTRUDER. APCH HAD ONLY MENTIONED THE LIGHT TURBOPROP ON RWY 28L WHICH DID NOT FIGURE IN THIS INCIDENT. I AM ALSO CONVINCED THAT THE PRACTICE OF ROUTINELY SPACING SIMULTANEOUS APCHS TO THOSE CLOSELY SPACED RWYS CAUSES FAR TOO MANY RA'S. SUCH FALSE WARNINGS WILL ONE DAY RESULT IN SLOW OR NO REACTION TO TCASII AND THAT WILL RESULT IN A MIDAIR COLLISION. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE ACFT'S FORWARD SPD WAS 160 KTS AND RPTR FEELS IT IS UNLIKELY THAT ANOTHER ACFT HAD OVERTAKEN HIS ACFT. THERE WAS NO EXPLANATION FOR THE WARNING, SO THE CAPT TOOK EVASIVE ACTION AND THE ACFT WAS AT 3000 FT BEFORE CTLR WAS ABLE TO ACKNOWLEDGE THE FLC'S MISSED APCH. RPTR STATES THAT FLT OPS MANUAL GIVES THE OPTION FOR TA SELECTION, ONLY, WHEN PARALLEL APCHS ARE IN USE, BUT THAT HE FEELS THIS POLICY MAKES NO SENSE. WHEN HE IS IN A BUSY TERMINAL ENVIRONMENT, HE WANTS ALL THE HELP HE CAN GET. RPTR BELIEVES THAT CLOSELY SPACED PARALLEL APCHS ARE DANGEROUS. IN HIS MIND THE PROB FALLS WITHIN ATC SYS MGMNT AND NOT IN AIRLINE OPERATIONAL POLICY OR FLC PROCS.

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.