Dear Asobo Studios: Thank you for breaking our airplanes, for the third time, with Sim Updates. We will now once again cease production while we try to understand what you have broken, how to fix it, then get everything updated for our customers (again).
That is all. Concorde is effectively grounded until it can be fixed and updated. Apologies to all.
ETA: CodenameJack has narrowed the issue down to the new Asobo fuel_system. Yes folks, a year and a half since launch, and they're still changing things as crucial to airplanes as fuel - this bug was reported during the beta by users, and yet SU9 was released anyway without the bug being fixed. Do we now fix it our end? Will Asobo issue a patch? Will the patch then break our fix? The beta system is of absolutely no use if Asobo do not act on crucial issues such as these *before* going live with their updates.
The fighter jets (F-14, F-15 and F-15) and PT-17 Stearman are still on the older fuel system, so appear unaffected at this time.