I am also having this issue with the QW 787. As stated in the QW forum by the dev's, this is a GSX issue due to the "Altitude Freeze".
The problem doesn't obviously anything to do with GSX, and I don't know what they mean with "Altitude Freeze" in relationship to GSX. The ONLY time in which GSX ever freezes the user airplane, is during Pushback, the exact moment the pushback guy says "start at will", and it will be unfrozen back to normal when he says "set parking brakes" at the end of the pushback.
The reason why GSX requires to freeze the airplane while it's pushing it, is to prevent the plane own ground handling would interfere with the pushing.
There are no other cases in which GSX ever freeze the airplane so, it's not possible that the plane would be already frozen when you just start the services.
And of course, GSX sets a custom variable ( L:FSDT_Var_Frozen ), which is set to 1 and 0 when the airplane is frozen/unfrozen (if reading the standard variable wasn't enough), and airplane developers can read it, to do whatever they need to do in case GSX pushing might eventually cause issues to their own custom system simulations.
If the Parking Brake status is not being the detected (so, nothing to do with Freeze, since it's not during Pushback ), the most likely causes are:
- The airplane use a custom variable for the Parking brakes instead of the standard one, so GSX config should be updated with it.
- This custom variable might not have been initialized in the same way when the airplane is started from Cold&Dark