B757 FLT CREW REPORTS 19000 POUND LOAD MANIFEST ERROR INTRODUCED DURING MANUAL CALCULATIONS BY FO. ERROR DISCOVERED POST FLIGHT.

Narrative

DURING THE PREPARATION OF THE LOAD MANIFEST; CRITICAL NUMERICAL INFO WAS TRANSPOSED FROM THE LOAD INFO SHEET TO THE LOAD MANIFEST. THIS DATA IS MANUALLY XFERRED TO THE LOAD MANIFEST; AND THEN MANUALLY CONVERTED INTO AN INDEX NUMBER THAT IS PLACED ON THE LOAD MANIFEST. THE PROCESS IS CONDUCTED IN A HIGH WORKLOAD ENVIRONMENT WITH MANY INTERRUPTIONS AND DISTRS. ON THE DAY OF THE INCIDENT WE WERE OPERATING AS AN INTL 2 PLT CREW. THIS IS VERY UNUSUAL FOR OPS AT THIS AIRLINE AND INCREASES THE WORKLOAD NORMALLY ENCOUNTERED BY THE FLT DECK CREWS. AS THE LOAD MANIFEST WAS BEING PREPARED; MANY PEOPLE CAME AND WENT FROM THE FLT DECK. THESE WORKERS INCLUDED MAINT PERSONNEL; FLT ATTENDANTS; GND SVC AGENT; THE LCL HANDLER AND OTHERS EACH WITH AN INQUIRY OR NEED FROM EITHER MYSELF OR THE CAPT. DURING A 3 PLT OP; MUCH OF THIS TFC TO AND FROM THE FLT DECK IS AVOIDED OR INTERCEPTED BY THIRD PLT. ON THIS DAY IT FELL TO WHICHEVER OF THE 2 PLTS LEAST ENGAGED TO HAND THE INQUIRES. ALTHOUGH I HAVE NOT YET REVIEWED THE DOCUMENTATION FROM THIS FLT; I AM TOLD THAT LOAD FIGURES WERE TRANSPOSED RESULTING IN AN 8800 KG WT DISCREPANCY. THIS COULD HAVE ONLY RESULTED FROM THE AMOUNT OF TFC MOVING ON AND OFF THE FLT DECK CREATING MANY DISTRS. AT TIMES DURING THE PREFLT PERPETRATIONS AS MANY AS 5 PEOPLE AT ONCE WERE ON THE FLT DECK OF THE B757; ALL TRYING TO ACCOMPLISH TASK NECESSARY FOR OUR DEP. PREVENTION OF A POSSIBLE RECURRENCE COULD BE ACHIEVED BY LIMITING THE TFC TO AND FROM THE FLT DECK. ADDITIONALLY; ADDING A PROTOCOL THAT REQUIRES A PERSON ENTERING THE FLT DECK TO WAIT FOR ACKNOWLEDGEMENT BY THE FLT CREW BEFORE PRESENTING INFO OR MAKING INQUIRIES COULD ALSO HELP IN REDUCING DISTRS AT CRITICAL POINTS. DISTRS IN A HIGH WORKLOAD ENVIRONMENT CANNOT COMPLETELY BE AVOIDED. HOWEVER; ADDING THE SUGGESTED PROTOCOL TO THE COMPANY PROCS MIGHT REDUCE THE NUMBER OF CRITICAL POINT DISTR ENCOUNTERS ON THE FLT DECK.