B777 - One Fuel Centre Tank Pump U/S

[Billboeing]

Hello gentleman,

aircraft is dispatched with one inoperative fuel pump in the centre tank.
According MEL you have to reduce the maximum zero fuel weight limit by the amount of Centre Tank fuel.
Now, lets assume, in the worst scenario immediately after departure I will lose the second center pump, I carry all the fuel in the center tank and cannot use it?
Also, with the remaining Fuel in the main tanks I will not reach my destination?
And, I must be prepared for an overweight landing because I exceed the max landing weight?

Would appreciate some feedback.

[wiggy]

Now, lets assume, in the worst scenario immediately after departure I will lose the second center pump, I carry all the fuel in the center tank and cannot use it?

That pretty much it, as is often the case the MEL is written to cover the consequences of a second failure on the same system.

Second pump fails: therefore centretank fuel stuck where it is and no longer available...it's effectively cargo/deadload, hence the weight and balance implications

Also throughout the flight you must always have enough fuel in the wing tanks to get somewhere suitable, again in case you suddenly lose the one remaining pump and cannot access the centretank fuel.

That is it in simple terms.

[Billboeing]

Hey Wiggy,

many thanks for your quick reply;)

[Cough]

Why would you land overweight, if actual ZFW+centre tank fuel can't exceed MZFW?

[McNugget]

MLW is greater than MZFW on the 777, so no landing weight issues with 'deadload' fuel locked inside the centre tank.

Thereafter, normal rules apply regarding overweight landings.

[FullWings]

MLW is greater than MZFW on the 777
You’re right. Is there any aircraft where this isn’t true...?

[8che]

Try having a look at scavenge pump failure as well. Same result except you will be already airborne when it happens.