Narrative:

The company operates 1 non-standard fleet widebody transport. One of the main differences is the maximum structural takeoff gross weight. That weight is 430000 pounds. The basic operating weight is the same as the rest of the fleet. To alert the crew member to the difference in the maximum takeoff weights, the company uses a white colored widebody transport maximum allowable takeoff gross weight form for the standard fleet aircraft and a yellow colored form for the non standard airplane. When I arrived at the gate to start the preflight, I discovered that the aircraft had been switched to the non-standard fleet airplane. I threw the white widebody transport maximum allowable takeoff gross weight form away and pulled a yellow form from the aircraft supply on board. At this point, I was cognizant of the different weights. The captain quickly scrutinized the paperwork and decided we needed more fuel. He left the cockpit to speak to dispatch about a new flight plan and to order more fuel. To complete the widebody transport maximum allowable takeoff gross weight form and the weight and balance form, there are 2 numbers that are required off the flight plan. They are: the planned fuel burn and the maximum ETP1 payload. I didn't have a flight plan yet so I didn't attempt to fill out either of these forms or even start the process. However, due to the tailwind condition that existed for takeoff, I had been busy checking the performance charts for different runways and different flap settings. I noted this on a separate piece of paper. Finally, the flight plans arrived and I started filling out the forms with the new ATIS information. The first officer called ground and obtained the wind for the runway we were going to use and I used this wind information for performance calculations. This would have been the most restrictive weight for the standard fleet aircraft. However, the most restrictive weight for the airplane we were flying was the maximum structural takeoff weight. In the heat of the battle we all forgot what airplane we were in as far as maximum gross takeoff weight is concerned. In our minds we had convinced ourselves that the most restrictive weight was the runway performance weight. Consequently, when I filled out the widebody transport maximum allowable takeoff gross weight form and the weight and balance form that number was the one that was used. When I was filling out this form, I didn't see a yellow form. I just saw a form that needed to be completed before I finished the weight and balance form. At the top of climb, when I had a few extra moments, I began taking the competed paperwork out of the engineer's desk and transferring it to the company envelope. Then I saw a yellow form! Supplemental information from acn 222709: airplane delivered to gate with inoperative standby horizon. Mechanic pretended to swap part, but actually reinstalled same unit! Departure delay due last min tracking down part and reinstalling. Note: captain was denied access to his duty station during this maintenance work. Company's flight plan was unrealistic in altitude (37000 ft hardly ever attainable on this flight) and fuel remaining at destination (17000 pounds). This original projection has us going to an island over 2000 NM in the middle of the pacific ocean with little reserve, no diversion capability, inaccurate navigation equipment (omega) at an altitude 4000 ft above what we know to be normally attainable with our operation.

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Original NASA ASRS Text

Title: OVERWT TKOF. WT AND BAL.

Narrative: THE COMPANY OPERATES 1 NON-STANDARD FLEET WDB. ONE OF THE MAIN DIFFERENCES IS THE MAX STRUCTURAL TKOF GROSS WT. THAT WT IS 430000 POUNDS. THE BASIC OPERATING WT IS THE SAME AS THE REST OF THE FLEET. TO ALERT THE CREW MEMBER TO THE DIFFERENCE IN THE MAX TKOF WTS, THE COMPANY USES A WHITE COLORED WDB MAX ALLOWABLE TKOF GROSS WT FORM FOR THE STANDARD FLEET ACFT AND A YELLOW COLORED FORM FOR THE NON STANDARD AIRPLANE. WHEN I ARRIVED AT THE GATE TO START THE PREFLT, I DISCOVERED THAT THE ACFT HAD BEEN SWITCHED TO THE NON-STANDARD FLEET AIRPLANE. I THREW THE WHITE WDB MAX ALLOWABLE TKOF GROSS WT FORM AWAY AND PULLED A YELLOW FORM FROM THE ACFT SUPPLY ON BOARD. AT THIS POINT, I WAS COGNIZANT OF THE DIFFERENT WTS. THE CAPT QUICKLY SCRUTINIZED THE PAPERWORK AND DECIDED WE NEEDED MORE FUEL. HE LEFT THE COCKPIT TO SPEAK TO DISPATCH ABOUT A NEW FLT PLAN AND TO ORDER MORE FUEL. TO COMPLETE THE WDB MAX ALLOWABLE TKOF GROSS WT FORM AND THE WT AND BAL FORM, THERE ARE 2 NUMBERS THAT ARE REQUIRED OFF THE FLT PLAN. THEY ARE: THE PLANNED FUEL BURN AND THE MAX ETP1 PAYLOAD. I DIDN'T HAVE A FLT PLAN YET SO I DIDN'T ATTEMPT TO FILL OUT EITHER OF THESE FORMS OR EVEN START THE PROCESS. HOWEVER, DUE TO THE TAILWIND CONDITION THAT EXISTED FOR TKOF, I HAD BEEN BUSY CHKING THE PERFORMANCE CHARTS FOR DIFFERENT RWYS AND DIFFERENT FLAP SETTINGS. I NOTED THIS ON A SEPARATE PIECE OF PAPER. FINALLY, THE FLT PLANS ARRIVED AND I STARTED FILLING OUT THE FORMS WITH THE NEW ATIS INFO. THE FO CALLED GND AND OBTAINED THE WIND FOR THE RWY WE WERE GOING TO USE AND I USED THIS WIND INFO FOR PERFORMANCE CALCULATIONS. THIS WOULD HAVE BEEN THE MOST RESTRICTIVE WT FOR THE STANDARD FLEET ACFT. HOWEVER, THE MOST RESTRICTIVE WT FOR THE AIRPLANE WE WERE FLYING WAS THE MAX STRUCTURAL TKOF WT. IN THE HEAT OF THE BATTLE WE ALL FORGOT WHAT AIRPLANE WE WERE IN AS FAR AS MAX GROSS TKOF WT IS CONCERNED. IN OUR MINDS WE HAD CONVINCED OURSELVES THAT THE MOST RESTRICTIVE WT WAS THE RWY PERFORMANCE WT. CONSEQUENTLY, WHEN I FILLED OUT THE WDB MAX ALLOWABLE TKOF GROSS WT FORM AND THE WT AND BAL FORM THAT NUMBER WAS THE ONE THAT WAS USED. WHEN I WAS FILLING OUT THIS FORM, I DIDN'T SEE A YELLOW FORM. I JUST SAW A FORM THAT NEEDED TO BE COMPLETED BEFORE I FINISHED THE WT AND BAL FORM. AT THE TOP OF CLB, WHEN I HAD A FEW EXTRA MOMENTS, I BEGAN TAKING THE COMPETED PAPERWORK OUT OF THE ENGINEER'S DESK AND TRANSFERRING IT TO THE COMPANY ENVELOPE. THEN I SAW A YELLOW FORM! SUPPLEMENTAL INFO FROM ACN 222709: AIRPLANE DELIVERED TO GATE WITH INOP STANDBY HORIZON. MECH PRETENDED TO SWAP PART, BUT ACTUALLY REINSTALLED SAME UNIT! DEP DELAY DUE LAST MIN TRACKING DOWN PART AND REINSTALLING. NOTE: CAPT WAS DENIED ACCESS TO HIS DUTY STATION DURING THIS MAINT WORK. COMPANY'S FLT PLAN WAS UNREALISTIC IN ALT (37000 FT HARDLY EVER ATTAINABLE ON THIS FLT) AND FUEL REMAINING AT DEST (17000 POUNDS). THIS ORIGINAL PROJECTION HAS US GOING TO AN ISLAND OVER 2000 NM IN THE MIDDLE OF THE PACIFIC OCEAN WITH LITTLE RESERVE, NO DIVERSION CAPABILITY, INACCURATE NAV EQUIP (OMEGA) AT AN ALT 4000 FT ABOVE WHAT WE KNOW TO BE NORMALLY ATTAINABLE WITH OUR OP.

Data retrieved from NASA's ASRS site as of July 2007 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.