Narrative:

ATC advised us (aircraft X) of traffic over the bay for the right runway. Aircraft X acknowledged the traffic and was cleared 'to maintain visual separation' and cleared visual approach to 28L. Aircraft Y was cleared visual to 28R and advised to keep up speed. Aircraft X intercepted final to 28L utilizing the localizer and slowed to final approach speed. (Below 150 KTS). Aircraft Y appeared to intercept final for 28R by continuing to close in on our position (we were already established on localizer) from the right; and was exactly abeam our position as he came closer to his extended final. As we were already slowed by approach control and now configured; we could not slow any further to create any longitudinal separation with the aircraft Y; and we could not increase our speed as that would have put us ahead of the smaller aircraft (aircraft Y) and caused a wake turbulence issue. Although the final positioning of the 2 aircraft was not apparent during the initial vectoring due to the opposing entry points and relative position further out; with hindsight I can conclude that at no time was my aircraft going to be behind aircraft Y and ATC was struggling to keep us from being ahead of aircraft Y and settled on us being abeam each others position. We flew the initial part of the final approach exactly wingtip to wingtip with the aircraft Y in VFR conditions but having (an assumed) higher final approach speed; which caused us difficulty in not passing aircraft Y's position abeam us on final. We were not advised of aircraft Y's final approach speed. After contacting sfo tower; we were cleared to land on 28L. Aircraft Y announced to us; on the frequency; something to the effect that they were advised to fall back from the abeam position. I took that to mean that aircraft Y was assuming and accepting responsibility for his wake turbulence avoidance; and I did not need to avoid passing forward of his position. Aircraft Y began to slow and fall behind by several plane lengths prior to touchdown. At no time were we aft of the aircraft Y's position and were forward of his position only when he slowed and fell aft of us. Although we were the aircraft assigned 'maintain visual separation' and we were the heavy that had to keep from passing the large aircraft to our right; aircraft Y had the only tool to accomplish any separation and that was to maintain a high speed and when he needed to slow; he had to assume wake turbulence responsibility even though he really had no way to know if there would be a wake problem. I recommend that in the future; all heavy aircraft be excluded from the simultaneous visual approach situation that includes (and is the specific goal of approach control) to place 2 aircraft wingtip to wingtip on final. I suspect that they are doing this to facilitate departures on the perpendicular runway complex of 1R and 1L. If a heavy is included in the simultaneous visuals; then it should only be the aircraft joining from the east (over the bay) and be positioned by vectors; well aft of the left-side aircraft; which will always be established on extended final earlier then the right-side aircraft. The runway center lines of 28R and 28L are only 750' apart which leaves a heavy aircraft as close as 500' wingtip separation; if both aircraft are exactly on center line; closer if either or both aircraft are even slightly to the inside of their course. The heavy aircraft generally have higher approach speeds than others and are further encumbered by the wake turbulence considerations. In this case; each aircraft landed without further incident.

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Original NASA ASRS Text

Title: A330 Captain reports being cleared for the visual 28L and instructed to maintain visual separation with traffic for 28R. The A320 traffic joins wingtip to wingtip and the faster A330 eventually pulled ahead and was unable to maintain visual separation.

Narrative: ATC Advised us (Aircraft X) of traffic over the bay for the right runway. Aircraft X acknowledged the traffic and was cleared 'to maintain visual separation' and cleared visual approach to 28L. Aircraft Y was cleared visual to 28R and advised to keep up speed. Aircraft X intercepted final to 28L utilizing the localizer and slowed to final approach speed. (below 150 KTS). Aircraft Y appeared to intercept final for 28R by continuing to close in on our position (we were already established on LOC) from the right; and was exactly abeam our position as he came closer to his extended final. As we were already slowed by approach control and now configured; we could not slow any further to create any longitudinal separation with the Aircraft Y; and we could not increase our speed as that would have put us ahead of the smaller aircraft (Aircraft Y) and caused a wake turbulence issue. Although the final positioning of the 2 aircraft was not apparent during the initial vectoring due to the opposing entry points and relative position further out; with hindsight I can conclude that at no time was my aircraft going to be behind Aircraft Y and ATC was struggling to keep us from being ahead of Aircraft Y and settled on us being abeam each others position. We flew the initial part of the final approach exactly wingtip to wingtip with the Aircraft Y in VFR conditions but having (an assumed) higher final approach speed; which caused us difficulty in not passing Aircraft Y's position abeam us on final. We were not advised of Aircraft Y's final approach speed. After contacting SFO Tower; we were cleared to land on 28L. Aircraft Y announced to us; on the Frequency; something to the effect that they were advised to fall back from the abeam position. I took that to mean that Aircraft Y was assuming and accepting responsibility for his wake turbulence avoidance; and I did not need to avoid passing forward of his position. Aircraft Y began to slow and fall behind by several plane lengths prior to touchdown. At no time were we aft of the Aircraft Y's position and were forward of his position only when he slowed and fell aft of us. Although we were the aircraft assigned 'maintain visual separation' and we were the Heavy that had to keep from passing the Large aircraft to our right; Aircraft Y had the only tool to accomplish any separation and that was to maintain a high speed and when he needed to slow; he had to assume wake turbulence responsibility even though he really had no way to know if there would be a wake problem. I recommend that in the future; all heavy aircraft be excluded from the simultaneous visual approach situation that includes (and is the specific goal of approach control) to place 2 aircraft wingtip to wingtip on final. I suspect that they are doing this to facilitate departures on the perpendicular runway complex of 1R and 1L. If a Heavy is included in the simultaneous visuals; then it should only be the aircraft joining from the east (over the bay) and be positioned by vectors; well aft of the left-side aircraft; which will always be established on extended final earlier then the right-side aircraft. The runway center lines of 28R and 28L are only 750' apart which leaves a heavy aircraft as close as 500' wingtip separation; if both aircraft are exactly on center line; closer if either or both aircraft are even slightly to the inside of their course. The Heavy aircraft generally have higher approach speeds than others and are further encumbered by the wake turbulence considerations. In this case; each aircraft landed without further incident.

Data retrieved from NASA's ASRS site as of April 2012 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.