Narrative:

Air carrier X making a visual approach to runway 28R. Tower cleared us to land. A bizjet in front of us was also cleared to land on runway 28R. Spacing between aircraft had reduced to a point that tower, in an apparent effort to accommodate both aircraft, requested the bizjet to spend minimum time on the runway after landing and our aircraft to s-turn to the right. Both aircraft followed instructions and lndgs were completed. A third airplane, air carrier Y, was nearly abeam us and slightly higher conducting an approach to the parallel runway 28L. We maintained visual separation as instructed by approach control from approximately 12 mi to landing. During landing we heard air carrier Y crew express concern to tower that s-turning one aircraft on a parallel approach with another was not a good idea, and that our aircraft had initiated a turn into their aircraft. The tower controller stated that he had seen our maneuver and that we had initiated a s-turn to the right, away from their aircraft. We did not see the situation as described by the other crew. It was possible that they did not see our initial turn away from runway 28R centerline and first saw us when we turned back toward the runway 28R centerline to rejoin the final. At all times we had visual contact with the other aircraft, and at no time did we go left of runway 28R centerline. Supplemental information from acn 252341: during the course of a published visual approach to runway 28R at sfo, the tower asked us to make an s-turn for spacing on an light transport jet ahead. This turn was executed just inside the bridge to the right. An air carrier Y was in visual contact above us for the left runway. At the completion of the turn he was above and slightly ahead of us. He was in sight throughout the maneuver. The air carrier Y flight made a comment after landing to the tower regarding their request for us to make an s-turn on a parallel approach. The s-turn and landing were uneventful from our standpoint. Supplemental information from acn 252063: at approximately 3 mi out the sfo tower told air carrier X north the right to begin s-turns to increase separation. At approximately 700 ft MSL (1 mi out) I was ahead of the right runway traffic so that he was in my blind spot (behind and to the right). My first officer literally screamed as the right runway traffic appeared to almost collide with us as he was turning back to return to runway alignment. The separation on a side-by-side 'formation' approach is minimal at best and with the other aircraft told to make s-turns, the separation became unacceptable. Once inside of bridge (6.0 DME) no deviations from course should be directed or allowed.

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Original NASA ASRS Text

Title: MULTIPLE RWY OP PARALLEL RWYS VISUAL APCHS ACR Y HAD NMAC WITH ACR X. SEE AND AVOID CONCEPT.

Narrative: ACR X MAKING A VISUAL APCH TO RWY 28R. TWR CLRED US TO LAND. A BIZJET IN FRONT OF US WAS ALSO CLRED TO LAND ON RWY 28R. SPACING BTWN ACFT HAD REDUCED TO A POINT THAT TWR, IN AN APPARENT EFFORT TO ACCOMMODATE BOTH ACFT, REQUESTED THE BIZJET TO SPEND MINIMUM TIME ON THE RWY AFTER LNDG AND OUR ACFT TO S-TURN TO THE R. BOTH ACFT FOLLOWED INSTRUCTIONS AND LNDGS WERE COMPLETED. A THIRD AIRPLANE, ACR Y, WAS NEARLY ABEAM US AND SLIGHTLY HIGHER CONDUCTING AN APCH TO THE PARALLEL RWY 28L. WE MAINTAINED VISUAL SEPARATION AS INSTRUCTED BY APCH CTL FROM APPROX 12 MI TO LNDG. DURING LNDG WE HEARD ACR Y CREW EXPRESS CONCERN TO TWR THAT S-TURNING ONE ACFT ON A PARALLEL APCH WITH ANOTHER WAS NOT A GOOD IDEA, AND THAT OUR ACFT HAD INITIATED A TURN INTO THEIR ACFT. THE TWR CTLR STATED THAT HE HAD SEEN OUR MANEUVER AND THAT WE HAD INITIATED A S-TURN TO THE R, AWAY FROM THEIR ACFT. WE DID NOT SEE THE SIT AS DESCRIBED BY THE OTHER CREW. IT WAS POSSIBLE THAT THEY DID NOT SEE OUR INITIAL TURN AWAY FROM RWY 28R CTRLINE AND FIRST SAW US WHEN WE TURNED BACK TOWARD THE RWY 28R CTRLINE TO REJOIN THE FINAL. AT ALL TIMES WE HAD VISUAL CONTACT WITH THE OTHER ACFT, AND AT NO TIME DID WE GO L OF RWY 28R CTRLINE. SUPPLEMENTAL INFO FROM ACN 252341: DURING THE COURSE OF A PUBLISHED VISUAL APCH TO RWY 28R AT SFO, THE TWR ASKED US TO MAKE AN S-TURN FOR SPACING ON AN LTT JET AHEAD. THIS TURN WAS EXECUTED JUST INSIDE THE BRIDGE TO THE R. AN ACR Y WAS IN VISUAL CONTACT ABOVE US FOR THE L RWY. AT THE COMPLETION OF THE TURN HE WAS ABOVE AND SLIGHTLY AHEAD OF US. HE WAS IN SIGHT THROUGHOUT THE MANEUVER. THE ACR Y FLT MADE A COMMENT AFTER LNDG TO THE TWR REGARDING THEIR REQUEST FOR US TO MAKE AN S-TURN ON A PARALLEL APCH. THE S-TURN AND LNDG WERE UNEVENTFUL FROM OUR STANDPOINT. SUPPLEMENTAL INFO FROM ACN 252063: AT APPROX 3 MI OUT THE SFO TWR TOLD ACR X N THE R TO BEGIN S-TURNS TO INCREASE SEPARATION. AT APPROX 700 FT MSL (1 MI OUT) I WAS AHEAD OF THE R RWY TFC SO THAT HE WAS IN MY BLIND SPOT (BEHIND AND TO THE R). MY FO LITERALLY SCREAMED AS THE R RWY TFC APPEARED TO ALMOST COLLIDE WITH US AS HE WAS TURNING BACK TO RETURN TO RWY ALIGNMENT. THE SEPARATION ON A SIDE-BY-SIDE 'FORMATION' APCH IS MINIMAL AT BEST AND WITH THE OTHER ACFT TOLD TO MAKE S-TURNS, THE SEPARATION BECAME UNACCEPTABLE. ONCE INSIDE OF BRIDGE (6.0 DME) NO DEVS FROM COURSE SHOULD BE DIRECTED OR ALLOWED.

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.