Narrative:

We had flown uneventfully from japan to sfo and were being vectored for an ILS runway 28R. We acquired the field visually while descending to 3000 ft on a base leg. We were cleared for the visual approach to runway 28R. We had briefed the ILS runway 28R and reviewed the quiet bridge visual runway 28R. (We had also flown the quiet bridge to runway 28R 3 days earlier.) as we continued turning final, I recommended to my first officer that he 'shoot for 1900 ft,' as recommended for a crossing altitude at the san mateo bridge. As I recall, I checked in with sfo tower reporting 15 DME on the visual to runway 28R. I do not recall our exact altitude, but recall that we were close to or at 1900 ft. We landed on runway 28R with no warnings or advisories from the tower and taxied to our gate. After some rest at the hotel, I reviewed the sfo 10-1 page and came to the conclusion that, during the approach, I very possibly exited the floor of the class B airspace. My company operation specifications (FMS) state that, during a visual approach to an airfield in class B airspace, we must remain in the class B airspace during the entire approach. Had we maintained our last assigned altitude of 3000 ft until intercepting the GS, this report would not have been submitted. This was day 6 of flying for me in the previous 10 days, but I do not believe fatigue was a factor. We were all very alert and all options (ILS/visual) for the approach had been reviewed. While the responsibility is ultimately mine, an altitude heads-up about my altitude from the tower could be beneficial in insuring my compliance with the airspace requirement, or a statement such as 'remain in the class B airspace, cleared the visual approach' might also be helpful in a similar situation.

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Original NASA ASRS Text

Title: B747 LNDG SFO MAY HAVE EXITED CLASS B DURING VISUAL APCH.

Narrative: WE HAD FLOWN UNEVENTFULLY FROM JAPAN TO SFO AND WERE BEING VECTORED FOR AN ILS RWY 28R. WE ACQUIRED THE FIELD VISUALLY WHILE DSNDING TO 3000 FT ON A BASE LEG. WE WERE CLRED FOR THE VISUAL APCH TO RWY 28R. WE HAD BRIEFED THE ILS RWY 28R AND REVIEWED THE QUIET BRIDGE VISUAL RWY 28R. (WE HAD ALSO FLOWN THE QUIET BRIDGE TO RWY 28R 3 DAYS EARLIER.) AS WE CONTINUED TURNING FINAL, I RECOMMENDED TO MY FO THAT HE 'SHOOT FOR 1900 FT,' AS RECOMMENDED FOR A XING ALT AT THE SAN MATEO BRIDGE. AS I RECALL, I CHKED IN WITH SFO TWR RPTING 15 DME ON THE VISUAL TO RWY 28R. I DO NOT RECALL OUR EXACT ALT, BUT RECALL THAT WE WERE CLOSE TO OR AT 1900 FT. WE LANDED ON RWY 28R WITH NO WARNINGS OR ADVISORIES FROM THE TWR AND TAXIED TO OUR GATE. AFTER SOME REST AT THE HOTEL, I REVIEWED THE SFO 10-1 PAGE AND CAME TO THE CONCLUSION THAT, DURING THE APCH, I VERY POSSIBLY EXITED THE FLOOR OF THE CLASS B AIRSPACE. MY COMPANY OP SPECS (FMS) STATE THAT, DURING A VISUAL APCH TO AN AIRFIELD IN CLASS B AIRSPACE, WE MUST REMAIN IN THE CLASS B AIRSPACE DURING THE ENTIRE APCH. HAD WE MAINTAINED OUR LAST ASSIGNED ALT OF 3000 FT UNTIL INTERCEPTING THE GS, THIS RPT WOULD NOT HAVE BEEN SUBMITTED. THIS WAS DAY 6 OF FLYING FOR ME IN THE PREVIOUS 10 DAYS, BUT I DO NOT BELIEVE FATIGUE WAS A FACTOR. WE WERE ALL VERY ALERT AND ALL OPTIONS (ILS/VISUAL) FOR THE APCH HAD BEEN REVIEWED. WHILE THE RESPONSIBILITY IS ULTIMATELY MINE, AN ALT HEADS-UP ABOUT MY ALT FROM THE TWR COULD BE BENEFICIAL IN INSURING MY COMPLIANCE WITH THE AIRSPACE REQUIREMENT, OR A STATEMENT SUCH AS 'REMAIN IN THE CLASS B AIRSPACE, CLRED THE VISUAL APCH' MIGHT ALSO BE HELPFUL IN A SIMILAR SIT.

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.