Thanks for your reply.
Here's the information asked:
- Which quantity of Fuel you had on board before calling GSX
Various. From empty tanks to 10-20kg, 100kg (no precise values but always less than it will refuel).
- If you used Simbrief or not.
Both. Tried by using SB and tried just entering the predefined percentages as well as manually adding a random value in the fuel/payload menu of MSFS
- The precise, exact, procedure in GSX you followed, which quantity you selected (or Simbrief) and when, exactly.
When asking for refuel and after the truck arrives near the aircraft. As for the quantity, already explained in the previous answers.
As for the procedure, first I call the GPU to have some power in the aircraft and then call the fuel truck. When the truck arrives, I input or select the desired fuel and the truck just takes around 20kg from the fuel I have onboard (if my tanks are empty it doesn't take any of course) and just drives away saying that the refuel was complete.
Once again, this is only happening with the Longitude, as far as I've tested. Tried several other aircraft (Icon A5, Cessna 172, King Air 350, Kodiak 100, both tyre and amphibious) and all are working as they should, adding fuel and progressively.
UPDATE: After buying the Microsoft/ASOBO ATR I tried with the ATR 42 and the same happens with it. So far only the ATR and the Longitude are having this issue.