Narrative:

We were on localizer 28L at FAF. Descending on glide slope at 1400 AGL we had TCAS alert to descend 1200 fpm. [Another aircraft] overshot parallel approach on 28R from above; behind and right of our aircraft. We followed TCAS guidance to 900 ft AGL and had to abandon its direction due to terrain closure. At 1200 ft first officer visually acquired [the other aircraft] and said he was 1 plane length behind and 10 ft above. I accelerated 10 knots to gain distance. I had no other safe option but to continue. Can't go up or down - up hits [other aircraft] - down hits water. We selected TCAS to traffic advisory (TA) at 900 ft. Glad we had it in TA/RA (resolution advisory) during onset of approach. [Other aircraft] was assigned to follow us and not to overtake. They failed on both counts. Tower ordered [other aircraft] back onto their runway/approach; safely landed.

Google
 

Original NASA ASRS Text

Title: A319 Captain reported NMAC on approach to SFO Runway 28L when another aircraft overshot the parallel approach course.

Narrative: We were on localizer 28L at FAF. Descending on glide slope at 1400 AGL we had TCAS alert to descend 1200 fpm. [Another aircraft] overshot parallel approach on 28R from above; behind and right of our aircraft. We followed TCAS guidance to 900 FT AGL and had to abandon its direction due to terrain closure. At 1200 FT First Officer visually acquired [the other aircraft] and said he was 1 plane length behind and 10 FT above. I accelerated 10 knots to gain distance. I had no other safe option but to continue. Can't go up or down - up hits [other aircraft] - down hits water. We selected TCAS to Traffic advisory (TA) at 900 FT. Glad we had it in TA/RA (Resolution Advisory) during onset of approach. [Other aircraft] was assigned to follow us and not to overtake. They failed on both counts. Tower ordered [other aircraft] back onto their runway/approach; safely landed.

Data retrieved from NASA's ASRS site 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.