Fuel

EXT FUEL TANKS

After you have mounted or dismounted an external fuel tank in the fuel and payload dialog, you might have to close the dialog and reopen it to see that change proper, and to be able to set the level.

Conformal Fuel tanks

See CFTs

AIR TO AIR REFUELING

You can refuel with both AI or MP compatible tankers which operate a boom system. To perform aerial refueling set the AIR REFUEL switch to open (or press f) and get within the boom engagement zone of the tanker. Notice that this will also change how the fly-by-wire reacts to your stick inputs, so that you can make minute corrections more easily when close to the tanker.