AN ACR MLG MAY HAVE CROSSED A RWY WITHOUT CLRNC.

Narrative

WHEN WE RECEIVED OUR INITIAL TAXI INSTRUCTION AT SFO; WE WERE CLRED TO TAXI TO RWY 28L VIA TXWY A; TXWY F; HOLD SHORT RWY 1L. WHILE HOLDING SHORT OF RWY 1L; GND CTL CLRED AN ACFT TO CROSS RWY 1L; HOLD SHORT RWY 1R AND THEN CONTACT TWR ON 120.5. THE CALL SIGN FOR THE CLRED ACFT WAS BLOCKED BY ANOTHER RADIO XMISSION. I ASKED THAT GND CTL REPEAT HIS CLRNC BECAUSE IT WAS BLOCKED. HE REPEATED THE CLRNC; AND THIS TIME WE HEARD OUR CALL SIGN. I READ BACK THE CLRNC; THE CAPT THEN PROCEEDED TO CROSS RWY 1L (WITH AN ACFT HOLDING IN POS ON RWY 1L). AFTER WE CROSSED RWY 1L; SHORT OF RWY 1R; I CONTACTED THE TWR ON 120.5. THE TWR INFORMED US THAT WE HAD CROSSED RWY 1L WITHOUT CLRNC. I TOLD TWR THAT GND CTL HAD CLRED US TO CROSS RWY 1L. HE REPLIED THAT THE TWR SUPVR WOULD REVIEW THE TAPE. I BELIEVE A CONTRIBUTING FACTOR IS THAT IT IS VERY INCONSISTENT WHO CTLS THE XING OF ACTIVE RWYS. SUPPLEMENTAL INFO FROM ACN 319063: UPON ARR AT MSY; I CALLED SFO TWR; BUT THE PERSON IN CHARGE HAD GONE HOME. I LEFT MY NAME AND TELEPHONE NUMBER. THE COPLT AND I ARE VERY SURE OF OUR ACTIONS BASED ON OUR ISSUED CLRNCS.