737 centre tank pump u/s
 

Guys, heres one for ya. If you have a centre tank pump u/s, the boeing dispatch guide states that you leave the crossfeed open and the remaining pump on. Is this a wise configuration for t/o or is it better to use the wing tanks for t/o and then in the climb out turn on the cross feed and remianing centre tank pump and begin using the centre tank. I am all ears on this one.

Bearcat,
I fail to see why you want to use a proceedure other than that published in the Boeing DDG. I imagine your company and its insurers might well be displeased. http://www.pprune.org/ubb/NonCGI/frown.gif

Bearcat,

You`re right. The procedure you`re describing is exactly the way we operate our 737`s. We leave the crossfeed open, except during T/O and Landing.
I have no copy of the original Boeing DDG, but this is how our company operates, and I guess it`s the same in the Boeing papers.
This is the same reason we have to turn the crossfeed closed for single engine landings.

No guys, I dont do my own thing and am by the book. All I am asking is the Boeing Dispatch Deviation guide reading into if you have a centre tank pump u/s and you are operating under the mel and you have 2000kgs in the centre tank...for take off am I correct in the reading that you have the cross feed open and the remaining centre tank fuel pump on? Having a cross feed open on t/o is not up my alley. Enlighten me chaps

Right...See if you can make sense of this.
The centre tank pumps have a higher output than the wing tank pumps, which is why the fuel in the centre tank is automatically used first. With one centre pump inop the pressure in the fuel manifold is still provided by the remaining higher rated centre pump. The wing pumps are "idleing" if you like and so not pumping any fuel into the feed manifold, they are waiting for the centre pump pressure to drop below their output rating. With one centre pump running and the crossfeed open the pump is feeding both engines from the centre tank (with the crossfeed closed the pump will only feed its associated engine and the other engine will be fed by its associated wing tank pump). Once the centre fuel has been used its pump can be switched off and the crossfeed closed. So if the crossfeed is closed with one centre tank pump switched on, you"ll soon have a fuel imbalance.

Thanks Spanner