Hi again Thomas. I can confirm from more testing that the issue I was experiencing is due to fuel depletion in the buffer tank. The flow rate and depletion seems specifically tied to the use of the afterburner and IMO, it seems a bit excessive compared to the other two internal tank flow/consumption rates. With even moderate afterburner use, the buffer tank goes dry very quickly (obviously due to it’s small capacity) which leaves still relatively high levels of fuel in the other two internal tanks to use (but rolls or inverted flight are no longer possible to remainder of the flight). I’m not sure how the Draken’s fuel system works but based on other fuel systems I’m familiar with, it seems logical that the buffer tank would be fed by whichever tanks are selected in order to maintain proper pressure & constant levels to prevent flame outs. Again, I do not know how the J35’s fuel system & tanks, just an observation. For the purpose of alleviating this particular issue, is there any way to easily make the other tanks feed to buffer tank to keep it at or near full throughout the fuel burn?