I am looking for information as to the fuel indices for the B747-400 tail tank. I have a fuel chart stating weight and index for the wing/center tanks and then an additional fuel chart for the Tail Tank.. Then I have a combined chart.
Looking at fuel tanks on drawing, I see that there are 6 wing tanks, one center tank and one tail/ Trim tank. In order to calculate the LITOW, I have added the indices from the winger/center tank to the tail tank index giving me a LITOW.
When tanks are full and max fuel is used, the combinded chart works out. Whe I used 5566kg tail tank fuel and a total TOF of 143000kg it alos works out fine with the combined chart. BUT when I used 7000kg it is about seven indices off. Can someone explain the "combined" chart for me. I have done the same calculations for the A380 without a "combined" chart and all is as it should be.