B747 CREW HAS OVERSIGHT IN WT CALCULATIONS BY 27 METRIC TONS AND DEPARTS WITHOUT ADJUSTING CALCULATIONS FOR TRIM; FUEL; OR V SPDS.

Narrative

IN DHAKA; BANGLADESH; ON A STOP-OVER FROM MADRAS; INDIA TO ISTANBUL; TURKEY; AN OVERSIGHT OCCURRED REGARDING THE PLANNED VERSUS ACTUAL PAYLOAD. OUR FLT; ALREADY IN DELAY; WAS BEING LOADED WITH FREIGHT. MY CREW AND I HAD COMPLETED AS MUCH OF THE PREFLT AS POSSIBLE. I HAD RECEIVED THE FLT PLAN PACKAGE AND REVIEWED THE INFO CONTAINED IN IT; WHICH INDICATED A PLANNED PAYLOAD OF 61 METRIC TONS. 2 HRS LATER; ONCE THE LOADING HAD BEEN COMPLETED. I REVIEWED THE WT AND BAL SHEET WHICH ZZZ REPRESENTATIVE HAD PREPARED. THE WT AND BAL SHOWED A NEW PAYLOAD OF 87 METRIC TONS. THE REPRESENTATIVE MADE NO MENTION OF THE ADDITIONAL 26 METRIC TONS OF FREIGHT BEYOND THE PLANNED PAYLOAD TO ANYONE IN THE CREW; NOR DID I CATCH THIS FACT ON THE WT AND BAL WHEN I LOOKED AT IT. FE ALSO CHKED OVER THE WT AND BAL AND FOUND IT TO BE IN ORDER. I COMPLETED THE DATA ENTRY INTO THE OPS COMPUTER; WHICH THE FO HAD BEGUN; BY ADDING THE ACTUAL TKOF GROSS WT AND CTR OF GRAVITY FROM THE WT AND BAL. I PRINTED A TKOF DATA CARD FROM IT; WHICH THE OTHER 2 CREW MEMBERS DOUBLECHKED. AN UNEVENTFUL TKOF AND DEP ENSUED. LATER AT CRUISE; ABOUT 1 HR 50 MINS INTO THE FLT; WE RECEIVED A MESSAGE VIA HF RADIO FROM DISPATCH ASKING US TO CONFIRM OUR PAYLOAD OF 87 METRIC TONS; WHICH HAD BEEN SENT TO THEM PREVIOUSLY IN OUR DEP MESSAGE. NATURALLY; THIS CAUGHT MY ATTN. I THEN COMPARED THE PLANNED PAYLOAD FROM THE COMPUTER FLT PLAN TO THE ACTUAL PAYLOAD OFF OF THE WT AND BAL SHEET AND NOTED THE 26 METRIC TON DIFFERENCE. I ASKED THE FE TO ROUGHLY CALCULATE HOW MUCH EXTRA FUEL WE WOULD BURN BECAUSE OF THE EXTRA UNPLANNED WT WE WERE CARRYING. I THEN RECONFIRMED THAT THE DEST WX WAS STILL VMC AND FORECASTED TO REMAIN SO WELL AFTER OUR ARR TIME. I THEN INITIATED A PHONE PATCH WITH DISPATCH TO REQUEST THAT THEY REMOVE THE NEED FOR AN ALTERNATE ARPT; AS WE WERE WITHIN 6 HRS OF OUR DEST ON AN INTL FLT PLAN AND THE WX AT THE DEST WAS VMC. THIS WOULD PROVIDE THE ADDITIONAL FUEL NECESSARY TO COMPENSATE FOR THE EXTRA UNANTICIPATED FUEL BURN. DISPATCH THEN COMPUTED THE FUEL NUMBERS AND PROVIDED US WITH A REDISPATCH; ENABLING US TO CONTINUE ON TO OUR INTENDED DEST WITHOUT INCIDENT. HAD THE REPRESENTATIVE NOTIFIED ME OR HAD I DISCOVERED THE ADDITIONAL UNEXPECTED PAYLOAD PRIOR TO DEP; I WOULD HAVE REQUESTED A NEW COMPUTER FLT PLAN FROM DISPATCH. HOWEVER; AFTER THIS OVERSIGHT HAD BEEN DISCOVERED; I TOOK AN APPROPRIATE COURSE OF ACTION TO ENSURE THE SAFE COMPLETION OF THIS FLT. AFTER THESE EVENTS TOOK PLACE; MY CREW AND I DISCUSSED THE LESSONS LEARNED FROM THIS EXPERIENCE. BREAKING THIS HABIT PATTERN ALLOWED THE UNANNOUNCED ADDITIONAL CARGO TO GO UNNOTICED. THE LESSON LEARNED HERE IS TO DOUBLECHK THE PAPERWORK LEST A PARTICULAR HABIT PATTERN IS BROKEN. MOREOVER; YYY HAS SINCE PUBLISHED THE FOLLOWING 'INTAM' IN AN EFFORT TO PREVENT THIS SORT OF MISTAKE FROM RECURRING BY STRENGTHENING THE PROC. THIS NEW PROC PROVIDES A METHOD TO MAKE CREWS CONSCIOUSLY AWARE OF ANY LARGE WT DIFFERENCES THAT MAY EXIST BTWN THE PLANNED TKOF GROSS WT AND PAYLOAD COMPARED TO THE ACTUAL ONES. ALTHOUGH THIS EVENT HAD A POSITIVE ENDING; THAT BEING THE ACFT REACHED ITS INTENDED DEST IN A SAFE AND TIMELY MANNER; THE LESSONS LEARNED FROM THIS SIT HAVE PROVED TO BE VALUABLE ONES.