WELL INTO THEIR FLT; B767-300 FLT CREW RECEIVE UNTIMELY DATALINK REVISIONS TO WEIGHT AND BALANCE INFORMATION FOR TKOF.

Narrative

WE RECEIVED OUR FINAL WT AND DATA RECORD VIA THE ACFT ACARS AT OUR DEP GATE AND ENTERED THE DATA INTO THE FMS. THE SELECTED RWY WAS RWY 26L WHICH IS THE ATC PREFERRED RWY FOR THE ASSIGNED DEP. RIGHT BEFORE PUSHBACK; AN UPDATED WT AND DATA RECORD WAS SENT ACCOUNTING FOR A 5500 LB INCREASE IN CARGO. THIS ADDITIONAL WT PUT US WHERE A HEADWIND WAS REQUIRED FOR A TKOF ON RWY 26L. WE DECIDED TO ASK FOR AND GOT FROM ATC; APPROVAL FOR A TKOF ON RWY 27R WHICH WAS SIGNIFICANTLY MORE FAVORABLE. THE TAXI; TKOF; CLB; AND INITIAL CRUISE WERE UNEVENTFUL. AN HR AFTER TKOF; WE WERE SENT A MESSAGE FROM OUR DISPATCHER SAYING AN ADDITIONAL 7500 LBS OF CARGO HAD BEEN ADDED THAT HAD NOT BEEN ACCOUNTED FOR ON THE WT AND DATA UPDATE WE RECEIVED BEFORE DEP AND THEREFORE; NOT ACCOUNTED FOR ON THE TKOF PERFORMED. SHORTLY THEREAFTER; WE RECEIVED A FULL FINAL WT AND DATA RECORD AND A NEW DISPATCH RELEASE; BOTH REFLECTING THE ADDITIONAL CARGO. THE NEW WT AND DATA RECORD SHOWED US OVERWT FOR ANY TKOF ON RWY 26L BUT NUMBERS FOR RWY 27R WERE AVAILABLE. WE ENTERED THE CORRECTED DATA INTO THE FMS AND CONFIRMED WITH OUR DISPATCHER THAT A LOAD AUDIT HAD BEEN INITIATED. THE REST OF THE FLT WAS UNEVENTFUL. THIS EVENT WAS APPARENTLY CAUSED BY A BREAKDOWN IN THE PROCS THAT LET US KNOW OUR ACFT WT AND ALLOW US TO SELECT A SUITABLE RWY AND ENTER THE PROPER TKOF SETTINGS. WHILE WE FOLLOWED OUR PROCS CORRECTLY; THE DATA WE BASED OUR TKOF SELECTIONS ON WAS INCORRECT AND COULD HAVE RESULTED IN A MORE SERIOUS EVENT. HAD WE TAKEN OFF ON RWY 26L WHICH ACCORDING TO OUR DATA WE WERE LEGAL TO DO; OUR ACTUAL WT; UNBEKNOWNST TO US; WOULD HAVE HAD US TAKING OFF ON AN INSUFFICIENT RWY. WE HAVE SUBMITTED AN OPS RPT ALONG WITH OUR DISPATCHER FOR REVIEW AND CORRECTIVE ACTION.