Help! Tank-to-Engine fuel tank imbalance

[JSACKS 0]

I am 2/3 of the way through a 5000nm flight in the 744.  For some time, I had a TANK/ENG illuminated on the upper EICAS and wasn't sure what to do.  After a long delay, I finally closed the X-feed for main 1 and main 4 and that seems to have put me in Tank/Eng mode.  However, here's the problem: I have a total of 85K fuel remaining.  Main 1 and 4 each have 29k of fuel while Main 2 and 3 have 14k each.  I cannot for the life of me figure out how to get fuel from main 1 and 4 transferred into main 2 and 3 so that the fuel load is balanced among all 4 tanks.  I thought I could X-feed the fuel from 1 and 4 easily, but the fuel synoptic doesn't show that this is possible.  Can anybody explain how to do this?  Thanks for any replies.

 

JS

:unsure:

[pschlute 37]

First, when you get the TANK/ENG illuminated you should close the crossfeeds and turn off the override pumps. If you do this in a timely fashion you will not get your problem.......anyhow.............

 

to correct the imbalance you now have, you do the following:

 

Open all four crossfeeds

Turn off tank 2+3 main pumps.

 

Tanks 1 and 4 will now supply fuel for all engines. When you have equalised tank quantities, you turn on 2+3 main pumps and close all crossfeeds.

[Avantime 81]

If you wait too long (e.g. with time compression) the tank-to-engine fuel imbalance will never resolve itself because you would've burnt too much fuel from the inner wing tanks. 

 

In that case you should go to the PMDG options menu - fuel - and apply the current total fuel figure to the aircraft. This will reset the fuel system and everything will be back in balance.

[kevinh 409]

One of the things I like about flying the 747 long haul is that you have to do a little bit of fuel management work en route. It gives you something to do in cruise. Not everyone's idea of fun of course.

[JSACKS 0]

Peter,

 

Thanks for your informative and helpful post.  Greatly appreciated.  I shall try this when I re-run part of the saved flight. 

 

JS

B)

[pschlute 37]

To be more correct, once tanks 1-4 are the same quantity, you should turn on 2+3 main pumps and close crossfeeds 1 + 4. Crossfeeds 2+3 remain open (auto) so as to keep the crossfeed manifold pressurised. This is important if you were to encounter an emergency situation which required engines 3 and 4 for example to be fed from tanks 1 and 2.

[JSACKS 0]

Thanks again, mate, very helpful indeed.  I'll be a cross feed expert by the time I've mastered this!

 

JS

[Matt2218 4]

Thanks again, mate, very helpful indeed.  I'll be a cross feed expert by the time I've mastered this!

 

JS

 

Definitely check out the fuel status page on the EICAS...really helps you understand what is going on when you flip the switches!