D Ramapriya wrote in
:

On Jan 23, 6:17 pm, Bertie the Bunyip wrote:
D Ramapriya wrote in
news:3a2a1504-fbc3-4f53-938e-
:

On Jan 23, 1:15 pm, WingFlaps wrote:

Does anyone know if both engines feed off the same tank(s) on
approach? It was at the end of a 10 hour flight wasn't it?

Don't know about the 777 but I've heard that on the A320 and A330,
there are six main pumps - two in the center tank and two in each
inner tank, and each engine is fed with one pump in the center tank
and with the two pumps in its own side inner tank. When inner tanks
reach low level, valves between outer and inner open and an
automatic gravity transfer occurs (on one of the A330 variants,
fuel transfers from center tank to wing tanks are managed through a
transfer valve).

Nope. You can't transfer fuel from one tank to another in flight.

Bertie


I could be wrong but ISTR that in a 777, if a center pump has low
output pressure with more than 1.1 t of fuel remaining, an EICAS
advisory message is displayed and the pilot has to operate a scavenge
system to transfer any remaining center tank fuel to the main tanks,
with actual transfer itself beginning only when either main tank
quantity is less than 13.1 t. ISTR also that in newer-generation 777s,
the scavenge system can be set to operate automatically.

I doubt it. There is no airliner I know of that allows fuel to be
transferred in flight.
I know a 777 pilot well. i'll ask him, but I'm pretty sure I know what
he'll say. We don't do scavenge, though. They feed. The only transfer is
to trim tanks.

Bertie