OVRD/JETT Main 2&3 Pump indication

[John H Watson]

The 0/1 logic is explained in a scavenge pump schematic:

Note that that is the old logic (with out the post-TWA modifications to prevent tank explosion)

[John H Watson]

The transition to "0" after 5 minutes is also modelled in PSX. I think PSX agrees with all these descriptions and diagrams. You need to wait 5 minutes for the change from green to cyan.

So what is your explanation for the photo? I can assure you, I didn't have the pumps running for 5 minutes, especially with an empty tank.

[Hardy Heinlin]

I can reproduce the photo situation in PSX instantly without a 5 minute delay when I cycle the APU or EXT power off and on.

However, it's strange that main tanks 2 and 3 aren't amber on the photo although there's a fuel imbalance.

[John H Watson]

However, it's strange that main tanks 2 and 3 aren't amber on the photo although there's a fuel imbalance.

Isn't the imbalance trigger point 2722kg for the inboard tanks? There is only 1300kg difference in the photo.

  https://aerowinx.com/board/index.php/topic,4733.msg50416.html#msg50416

[Hardy Heinlin]

OK, when I reproduced your photo in PSX, I had a 1000 lbs hysteresis remainder within the allowed tolerance :-) I can clear that by reentering the tank quantity on the Instructor. So, it's all normal.