A B777 WING PASSES OVER A B747'S WINGLET ACCORDING TO AN ACR CAPT RIDING IN THE CABIN AS THE B777 ON TXWY A1 PASSED BY A B747 HOLDING ON TXWY A NEAR THE APCH END OF RWY 1R AT SFO.

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MY PURPOSE IS TO HIGHLIGHT THE CLOSE TAXI ENVIRONMENT AT THE APCH END OF SFO RWY 1R; AND RECOMMEND AN APPROPRIATE NOTE BE ADDED TO THE SFO ARPT DIAGRAM. I WAS CAPT OF ACR X; A B777-200. WE WERE INSTRUCTED BY SFO GND CTL TO FOLLOW A B747-400 ON TXWY A TO SFO RWY 1R. NEARING THE APCH END OF RWY 1R WE SWITCHED TO SFO TWR (120.5). THE B747 WAS STOPPED ON TXWY A; ON THE CTRLINE; 10-20 FT SHORT OF THE HOLD SHORT LINE FOR RWY 1R. I WAS ON TXWY A ABOUT 200 YARDS BEHIND ACR Y WHEN SFO TWR INSTRUCTED ME TO PASS ACR Y ON TXWY A1; IF SUFFICIENT LATERAL WINGTIP CLRNC EXISTED. I HAD MY FO CHK THE SFO ARPT CHART AND VERIFY THAT NO NOTES PROHIBITED 2 WDB'S FROM PASSING ON THE SUBJECT TXWYS. USING THE PUBLISHED COCKPIT VISUAL REFS; IT APPEARED THAT THE SPACING WAS ADEQUATE TO PASS SAFELY. I ELECTED TO TAXI SLOWLY TO ALLOW ME TO STOP IF NECESSARY. DURING THE PASSING MANEUVER; I USED THE PUBLISHED COCKPIT VISUAL REFS TO MONITOR THE GND TRACK OF MY L WINGTIP (I CANNOT SEE MY WINGTIPS FROM THE B777 CAPT'S SEAT). IN ADDITION; I POSITIONED THE NOSEWHEEL ABOUT 3 FT TO THE R OF TXWY A1 CTRLINE TO ENSURE MAX WINGTIP CLRNC. I PASSED ACR Y UNEVENTFULLY AND COMPLETED THE TKOF FROM RWY 1R. ABOUT 1 HR AFTER TKOF; A COMPANY B747 FLEET TECHNICAL CAPT; DEADHEADING IN THE MAIN CABIN PASSED ME A NOTE. THE CAPT'S NOTE STATED THAT 'IT APPEARED TO HIM THAT MY L WINGTIP HAD PASSED OVER THE TOP OF THE R WINGLET ON ACR Y WHILE WE WERE TAXIING' BUT THAT NO CONTACT HAD OCCURRED. I THEN SPOKE WITH HIM AND VERIFIED THAT NO CONTACT HAD OCCURRED. I INFORMED HIM THAT FROM OUR COCKPIT REFS IT APPEARED THAT LATERAL WINGTIP SEPARATION EXISTED. AFTER ARR MY FO AND I PERFORMED A VISUAL INSPECTION OF THE L WINGTIP AND OBSERVED NO DAMAGE. IN ADDITION I HAD DISPATCH SEND AN ACARS MESSAGE TO ACR Y ASKING IF THEY HAD OBSERVED THE CLRNC OF MY WINGTIP WHEN I PASSED THEM ON TXWY A1 IN SFO. THE CREW OF ACR X SAID THAT THE OVERALL SPACING BTWN THE 2 AIRPLANES LOOKED OK TO THEM; BUT THAT THEY DID NOT OBSERVE THE SPECIFIC CLRNC DISTANCE AS MY WINGTIP PASSED NEAR THEIR R WINGLET.