Actually I wouldn't know how to do that, as I don't explicitly ask GSX for any fuel quantity.
The FBW A320, in the internal configuration that comes with GSX has been flagged to use the standard refueling so, you are supposed to have GSX displaying the fuel menu, which has quantities and the SimBrief button.
If you haven't see this menu, it's can be caused by either:
- The GSX toolbar icon Inactive. In the time from calling Refueling until the truck arrives, the GSX toolbar icon shouldn't be closed, otherwise GSX is unable to pop-up the following Fuel quantity menu.
OR
- The airplane configuration changed to Disable the "Show fuel/cargo dialog during refueling", which is what controls how GSX refuels the airplane. The default GSX configuration for the FBW A320 is to have the option Enabled so, if you changed it, it will work as an airplane with a custom refueling system.
I think this is not completely clear: having a "custom refueling system", doesn't necessarily mean the airplane has a separate interface to load Fuel, that alone is not an indication of a custom refueling system, what really means is the airplane has an internal refueling simulation that PREVENTS or make unsafe having GSX refueling it. The Fenix A320, for example, simply cannot be refueled by GSX, because it has its own internal fuel simulation, if an airplane just have a different interface, but still uses the standard fuel and is not actively rewriting the fuel variables, it can be refueled by GSX safely, and it cannot be considered a plane with a "custom" refueling system.
However, that doesn't mean you can't reconfigure it AS IF it used a custom fuel system and use it as such.
To make it even more clear:
- An airplane that uses the standard fuel system, which could be refueled by GSX, CAN be configured as having a custom Fuel system, and this will work just fine, provide the user will follow the instructions for an airplane with a custom fuel system, the only difference, there will be no GSX fuel quantities menu and GSX won't really refuel the airplane, but will only react to the refueling performed by the airplane.
- An airplane with a really custom fuel system CANNOT be refueled by GSX, so it should NOT be configured to use the standard fuel system, because it won't work.
So, it's ok if you changed the FBW configuration to flag it as having a custom fuel system, but then you'll have to follow the same procedure like with the Fenix or the PMDG, that is:
- Start with some initial quantity
- Call the GSX fuel truck and don't touch the fuel until the truck is in position
- AFTER you see the message asking to refuel the airplane with its own system, use whatever means the airplane has to refuel itself ( EFB, FMC, separate loader apps, etc. ) and be sure you ask for a quantity greater than the one you had initially.
- If the "Always refuel progressively" option is Enabled, GSX will simulate a progressive refueling simulation even if the plane loaded instantly, with a speed controlled by the GSX own fuel pump simulation.
- If the "Always refuel progressively" option is Disabled, GSX will show a very fast counter
- If the airplane refueling itself progressively, the refueling speed will happen with the rate the airplane is increasing fuel on itself
- If the quantity added is not greater than the one you had when you called the GSX truck, the truck will go away immediately, with *NO* fuel counter, not even a fast one.
Another thing I have noticed is that the amount of fuel reported by GSX is always far less than the amount of fuel acutally taken up by the aircraft - even when the animation ends correctly.
Be careful to the units of measure, the GSX fuel counter is always in US Gallons, regardless of the unit used in the sim or the airplane.
