Narrative:

During pushback from gate at sfo; I noticed multiple ground personnel running toward aircraft some raising the 'set brakes' hand signal. I queried my pushback crew 3 times to no avail before slowly setting brakes. First officer looked out his side to see the pushback tug a good 75 ft from the aircraft. We had rolled on our own for at least 50 ft. The tug and the communication coordination somehow (I still don't know how) became disconnected. The aircraft rolled onto taxiway a (previously cleared to do so by ground). The pushback was very smooth and the aircraft turned 90 degrees just when it was supposed to also. No close calls were apparent from the cockpit. Ground crew then wanted me to release brakes. I said (through the first officer's windows) no; not until we establish what was to be done. Once that was done and the pushback was then completed without incident.

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Original NASA ASRS Text

Title: B757-200 CAPTAIN REPORTS ACFT ROLLING FREE FROM TUG DURING PUSHBACK AND A GENTLE STOP WHEN IT BECAME APPARENT WHAT WAS HAPPENING.

Narrative: DURING PUSHBACK FROM GATE AT SFO; I NOTICED MULTIPLE GND PERSONNEL RUNNING TOWARD ACFT SOME RAISING THE 'SET BRAKES' HAND SIGNAL. I QUERIED MY PUSHBACK CREW 3 TIMES TO NO AVAIL BEFORE SLOWLY SETTING BRAKES. FO LOOKED OUT HIS SIDE TO SEE THE PUSHBACK TUG A GOOD 75 FT FROM THE ACFT. WE HAD ROLLED ON OUR OWN FOR AT LEAST 50 FT. THE TUG AND THE COM COORD SOMEHOW (I STILL DON'T KNOW HOW) BECAME DISCONNECTED. THE ACFT ROLLED ONTO TXWY A (PREVIOUSLY CLRED TO DO SO BY GND). THE PUSHBACK WAS VERY SMOOTH AND THE ACFT TURNED 90 DEGS JUST WHEN IT WAS SUPPOSED TO ALSO. NO CLOSE CALLS WERE APPARENT FROM THE COCKPIT. GND CREW THEN WANTED ME TO RELEASE BRAKES. I SAID (THROUGH THE FO'S WINDOWS) NO; NOT UNTIL WE ESTABLISH WHAT WAS TO BE DONE. ONCE THAT WAS DONE AND THE PUSHBACK WAS THEN COMPLETED WITHOUT INCIDENT.

Data retrieved from NASA's ASRS site as of January 2009 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.