[2.9.21.16552] Active pause causes cell 1 fuel to drop to 850 lbs

[Stickler]

As per the attached track, using active pause causes the fuel in cell 1 to reduce spontaneously to 850 lbs and prevents cell 1 from being refilled from the remaining cells.

This fuel jump is indicated on the fuel totalizer when holding the Feed Tank Check Switch, but not in the EFB.

Once active pause is disengaged, cell 1 fuel content as indicated on the totalizer jumps back to 1416 lbs. If active pause is then again enabled, fuel in cell 1 reduces to 850 lbs once more, and so on.

If active pause is kept enabled for too long, the aircraft will eventually flame out due to fuel starvation in cell 1 even though the EFB continues to indicate a full cell 1.

cell1_active_pause.trk

[Zabuzard]

Thanks for the track. Smells like you might have paused with Gs or some other kind of unusual force.
The EFB pulls the numbers straight from the internal object, so those numbers are definitely the truth.
Active Pause can be quite finicky to code though, so maybe some gremlins in the logic. Will have a look :)

[Zabuzard]

Fixed. Available for an upcoming update.

Interesting one. The tank mass you saw were the ~850 lbs fuel that are naturally trapped in the lower third of the fuel tank 1 due to its shape to overcome phases of inverted flight from which the submerged fuel pumps at the bottom pull fuel to feed the engines. Essentially, this is for negative Gs and any other sort of forces that yeet the fuel out of the bottom part where the engine feed pumps are installed. The shape of the tank allows for roughly 850 lbs to be trapped there under most circumstances, so the engine can bridge negative G for some time.

So far so good, this part is working correct.

Two things werent correct and I fixed it:

* The feed-tank switch was incorrectly displaying the actual fuel mass available to the engines instead of the tank 1 fuel mass, i.e. what the installed sensor would measure
* Active-Pause should get a special case handling and simply ignore the fact that the tank doesnt sense positive forces anymore (remember, during active-pause the aircraft is frozen in motion, so the code measures 0G, so most of the fuel went elsewhere)

[Stickler]

Excellent!