B737 flight crew reported by following several TCAS RA on charted visual side-by to SFO RWY28R resulted in a low altitude alert from tower with a CFTT event.
Synopsis
B737 flight crew reported by following several TCAS RA on charted visual side-by to SFO RWY28R resulted in a low altitude alert from tower with a CFTT event.
Narrative
SFO ATIS advertised charted visual flight procedures. We briefed and set up for the charted visual flight procedure 28L. Then when advised to expect 28R we set up the charted visual flight procedure 28R. But on the base leg ATC instructed us to turn to a heading and intercept the localizer; not the visual flight procedure course. I hand flew the intercept and remained to the center or right of the LOC course in order to avoid an RA. However at the same time another aircraft behind and above us was vectored onto the LOC for 28L. As they intercepted their LOC and descended we received a 'Traffic Traffic' followed by a descending TCAS RA. I complied with the RA. Once we received 'clear of conflict' we were in a position to continue the approach and we elected to continue. Shortly thereafter we received a second RA to descend; then to level off; then to descend again. The guidance required descending under the glide slope which triggered the 'Glide Slope' aural. We turned right slightly away from the parallel runway to get away from the blundering aircraft and received a low altitude alert from ATC. As soon as I got the 'clear of conflict' from the second RA at about 1000 MSL/AGL we went around. We completed all duties and checklists and landed uneventfully on 28L.
Second reporter narrative
While on approach to runway 28 right at San Francisco; we were told to intercept the localizer and keep parallel traffic in sight off to our left in order to maintain visual separation from them. I was sitting in the right seat and did not have the traffic in sight; but the captain did. As we proceeded straight in on the localizer; we received a traffic alert due to the Air Carrier next to us. Very soon after; TCAS commanded we descend. The pilot flying (captain) was already hand flying; so he started descending more than he already was on the glide slope and turned slightly to the right to further distance ourselves from the traffic. After the TCAS system said we clear of the conflict; the captain started making our way back over to the localizer; and onto the vertical path that we had departed from due to the RA. He still had visual contact with the conflicting traffic. Soon after getting back on the localizer; we received another TCAS RA to descend. By this point we were around 1100 feet AGL. We descended momentarily but then completed a go-around instead of descending more away from the conflicting aircraft. At this time; the Air Carrier next to us was already doing a go-around (I looked over and saw them in a climbing left turn) in response to their own RA to get distance from us. I was on the right side of the aircraft as pilot monitoring; and this was the first time I saw the conflicting traffic; though the captain had them in sight the whole time. After we completed a normal go around and 2nd approach; we landed safely in San Francisco.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.