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Guest 744nut

fuel imbalance 744F

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Guest 744nut

Hi guys,I left the flightdeck unattented for a while and when I came back there was a major fuel imbalance (tank 1&4 11.2 t tank 2&3 0.8 t). I missed an EICAS message "Fuel imbalance" however.Is this programmed in the PMDG fuel logic? regardsTon

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Guest Jacob Lee

Can you do a cross-feed to balance it?

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Guest Ray51

I flew from KMIA to KORD and noticed my #2 engine was burning fuel slightly more that the others. I had to rebalance fuel using the cross feed and pumps a couple of times. Mine never got more that 0.5 differance so I didn't get a fuel imbalance warning.Ray

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Guest Hawkeyeted

>I left the flightdeck unattented for a while and when I came>back there was a major fuel imbalance (tank 1&4 11.2 t tank>2&3 0.8 t). >I missed an EICAS message "Fuel imbalance" however.When your TOTAL fuel load is 120K (30K in each tank) you should turn off the Overide boost pumps and close the #1 and #4 cross-feed valves. This puts you in the "Tank-to-Engine" configuration and should eliminate your fuel imbalance problem.Keep in mind that when the center tank empties to approx 3k, you should shut off it's pumps. The center tank pumps will then scavenge the remaining 3K to the #2 tank.

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Guest 744nut

Hi guys,Thanks for the answers! As far as I can see there is no "Fuel XFER main 1+4" valve modelled, so I closed tanks 2 & 3 :-) I also found out (read the manual !) that an EICAS message "Fuel Imbalance" is modelled in the PMDG fuel logic. So it must be a glitch on my system :-)regardsTon

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Guest Hawkeyeted

>Hi guys,>>Thanks for the answers! As far as I can see there is no "Fuel>XFER main 1+4" valve modelled, so I closed tanks 2 & 3 :-) I>also found out (read the manual !) that an EICAS message "Fuel>Imbalance" is modelled in the PMDG fuel logic. So it must be a>glitch on my system :-)The #1 & #4 cross-feed valves ARE modelled. They are the outer most two cross-feed push buttons (the ones without covers on them), and are the ONLY two cross-feed buttons that should ever be closed!

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Guest 744nut

Hi Ted,Thanks for your help! The XFER main 1+4 valve is another one than the XFEED valve :-). I checked the manual (page 46 of the systems chapeter) and there it is confirmed that it is not modelled regardsTon

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Guest morvious

>Hi Ted,>>Thanks for your help! The XFER main 1+4 valve is another one>than the XFEED valve :-). I checked the manual (page 46 of the>systems chapeter) and there it is confirmed that it is not>modelled >>regards>>TonTon,My overhead panel says X-Feed 1 t/m 4, and those 4 are moddeld.

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Guest 744nut

"My overhead panel says X-Feed 1 t/m 4, and those 4 are moddeld."But I am talking about the XFER main 1+4 valve :-) this one is situated at the top of the OVHT on the right side of captain audio panel. It is a black switch with a red rim :-)groetTon

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Guest Hawkeyeted

Overhead panel, center column, box just below the ignition panel, just above the anti-icing panel, is the fuel control panel. Top row of four buttons. The two outer-most push buttons (unguarded) are the #1 and #4 cross-feed valves. You close those two valves when all tanks read 30K lbs (I'm not sure what they are supposed to be in KG's).

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A fuel imbalance message will not be created by this configuation, Ton. Fuel Imbalance messages are generated when there is an imbalance between one WING and another. i.e. when the fuel distribution is a hazard to lateral stability.http://forums.avsim.net/user_files/145586.jpgHope this helps.Rgds.Q>

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Guest 744nut

Ian, how is life!? Thanks for your explanation! I thought that when there is a difference between the outboard tanks (1+4) and the inner tanks (2+3) of....let me look :-) > 2.7 t the logic declares a ">fuel imbalance" (my example m1 11.2, m2 0.8, m3 0.8, m4 11.2) In your pic I should say that this is a ">fuel imbal 2+3" Missed this discussions!cheersTon

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Seems you're right, Ton... Oh, well, back to the classroom for me :("If you don't use it, you lose it"I'm sure the team will look into this... eventually )Cheers.Q>(Edit: Oddly, this type of imbalance is not even mentioned in my training notes or the maintenance manual... but I've just found it in our AOM)

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Guest 744nut

Hi Ian,Since a long time I use the AOM again too ;-) I understand why you can

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