Yes, I wasn't very clear. The warning horn drew my attention to the fuel imbalance, but the horn was because I hadn't turned the packs and bleed air back on after starting the engines. I did mention I was a bit rusty.

Yeah, you might want to use a checklist...if you missed the packs and bleeds you are not doing it right.

Ok, I made a test flight and a video of it, the issue is still present, the transfer rate during climb was around 20-25kg/min that means around 100kgs of unbalance each 4/5 minutes, also, the ground / air wrong logic is still present.I found again also te stby horizon issue but maybe is due to panel state loading.I'm updating the video on youtube, I will give you the link tomorrow morning (italian time)Just to complete the discussion about this issue, I must tell you that normally it is an hidden bug.Normally, as the pmdg is designed, and as per checklist, you will burn your center tank fuel BEFORE using fuel in the wings.So, normally, following checklists, if you are with 1900kgs of fuel in the left wing, your center tank is already empty.This doesn't mean that the bug is not present, but that cannot be noticed if the plane is used correctly.

Thanks for the information, Andrea. I was aware of the fuel scavenge system, but not the details of how it operated. I have flown the NGX several times previously, with varying fuel levels, without encountering this problem before. In this flight, both wing tanks were full and I had fuel in the center tank as well, and all fuel pumps were on. I'm not entirely sure the scavenge system is to blame in this instance though, since the fuel level in the #2 tank was going down at a rate of about 10 lbs every 15-20 seconds, while the #1 tank remained full. The fuel level in the center tank was also decreasing, but I expected that. Does the bug you described cause the fuel scavenge system to draw fuel out of the #2 tank instead of from the center tank? If so, where was that fuel going? Now that I think about it, the rate at which the fuel level in the center tank was decreasing may have been a bit slower than normal. I'll be attempting this flight again at some point, and I'll try to recreate this issue. @Chris: This is an excellent example of why checklists are good at combating complacency. I already knew that, though.

With left wing full the scavenge system is not active so there is no flow from tanks. Tere is also no flow between tank 2 to the others (except on ground but is not simulated as it requires an external panel).What you had MAYBE a problem that is related to an error in loading panel state which activated the scavenge system with full tank OR added fuel consuption from tank 2 also with center tank pumps on.The rate of 20 lbs each 20 seconds is similar to the rate of the simulated scavenge but maybe not related.Try again, make sure you have wing tank pump working (check for failures), turn off ctr tank pumps to see what happen.

Ok, I updated te video:http://www.youtube.com/watch?v=RZhWnfiNbN4The video shows on the FMC the fuel qty with a precision of 1 kg.The fligth was a test flight, so I've not followed cecklist to power it up.The video starts with airplane on ground, 1800kgs (at the gate) on each wing plus some fuel (re-added during fligth) in ctr tank. CTR tank pumps offDuring taxi and untill liftoff the fuel inside the center tank remained costant.After liftoff the scavenge starts to work, fuel in the left wing have a rate less than the right tank.The video continues by timing the transfer after a minute (then 2) of flight. The only forgotten point is that by reloading fuel on ctr tank will also turn back on the relative pumps.