crossfeed...open or closed?

[xfeed]

I am hoping that someone can help me understand the crossfeed a little better. I was watching a film about the A330 that had the fuel leak while over the North Atlantic causing both engines to stop after all fuel was exhausted. They didn't initially believe what the airbus computers were telling them and they went through some checks and placed the crossfeed to "on".

My question is this: Is there a difference between the crossfeed in an Airbus v a Boeing? I have read information about the Boeings in my studies and it appears that the crossfeed is always open or they will get a "fuel config" warning. I believe the only time they close it (if I remember correctly what I was told) would be if the tanks were not balanced correctly. Also, the checklists for Boeing (that I have seen) always lists the crossfeed open after the engines have been started.

If the information I have read is correct, why did the flight crew on the Airbus open the crossfeed more than five hours into the flight? I would think their QRH book would have instructed them to close the crossfeed.

Please remember that I am only a lowly student just beginning to take flying lessons. I don't pretend to know all of what I am talking about. I only know what I have read in my books and what I have learned from all of you here.

Cheers!

[BOAC]

For 737 Classic and NG, normal setting is 'CLOSED'. It is 'OPEN' when fuel balancing is req'd or an engine requires feeding from the 'opposite' tank.

[Earl]

On the 747 classic the manifold is to be pressurized in all critical phases of flight.
For instance on take off you would use the classic H pattern.
For landing one of these crossfeeds would be open to accomplish this.
Some airlines even go back to the H pattern to insure this.
Depends on your company procedures.
For instance on the 747 classic.
Fuel managment.
Set for landing,
Check all main tank fuel boost pump switches to on.
All main tank boost pump low press lights extingueshed.
Check No. 2 fuel crossfeed switch in the open position.
No 1,3,4 crossfeed switches in the closed position and all crossfeed lights extingushed.

Check your company SOPS.
As this may be different, but in all cases the manifold should be pressurized for T/O and landing.

[Kraut]

Generally speaking, the old QRH did not epmpahsize enough the problem of FUEL CROSSFEED in suspected FUEL LEAK situations.
The newer QRH have in bold figures reminders/hints like:

LEAK NOT FROM ENGINE or LEAK NOT LOCATED:

FUEL X FEED..................MAINTAIN CLOSED

that´s for the A-320. I guess it is about the same for the A-330.

Any 330 driver?

[xfeed]

Thanks for the responses so far. I would like further enlightenment, though it would seem (upon further reading) that in most aircraft the crossfeed remains closed unless an imbalance is noticed (but not a fuel leak). I think what has confused me was the 747. Perhaps it is a different breed from the others but I can remember many years ago, when riding up front with my father, the crossfeed was open. The EICAS showed a yellow "XFEED" warning until the crossfeed was open.

Unfortunately, my father is no longer around so I can't ask him. Maybe just one needs to be open (as Earl mentioned for the classic). I was only an ignorant teenager during that flight but was very interested in all aspects and all the details as I am today.

I appreciate your answers.

Cheers!