Was on the Monday 13 May QF1 SYD-SIN service. All passengers were on and the baggage compartments closed with the LL2 Door being the last one remaining open and the scheduled departure time had come and gone. The Captain came on PA and said the automated fuel management system had started to transfer fuel to the horizontal stabilisers at the rear for the plane to ensure weight and balance was maintained. Once this was done we got the final load sheet and were on our way. A question is this fuel transfer automated to the extent it kicks in without any manual intervention. Does the aircraft have to be stationary for weight and balance to be calculated?
Around the time that you start doing the coughpit preflight, you'll be sent a couple of numbers. One is the zero fuel weight, and the other, the zero fuel CoG. They are entered into an FMC, and will be used by the fuel system to calculate just where it will put the fuel. It then does that automatically.
In the last few minutes prior to push back, you'll get the final loadsheet. That will update those numbers, and will also give take off CoG and load control's calculation of the fuel distribution. We update those numbers in the FMC, and then enter TO setting, as well as check that the fuel figure what is actually in the trim tank. The FMC will have also calculated a TO setting, and that has to be within 1% of the figure on the final load sheet. If it isn't then you select the "auto fuel transfer" system. It's automatic in that once you turn it on, it will then move fuel until the two TO settings match. You can stop it once within 1%, but you'd almost always let it stop by itself, which it will do when the two match exactly.
All of this is done in the before start procedures, so you can't complete them, or the before start or after start checklists, until you've completed the loading entries.
Procedurally, it has to be done before push back. That closes a lot of the potential holes in the cheese. But, the system would work when you are taxiing, and you could enter the numbers into the FMC. Not a great idea though.
