Make sure the aircraft is aligned in a perpendicular position. Prevent cross-feeding between fuel tanks. Completetly drain fuel tanks of your aircraft. Fill in the non-useable amount of fuel according to your aircraft manual. Use the Universal DipStick to check the initial fuel level. This lower most level represents the zero-level of useable fuel. Mark it on the back of this scale card. Fuel the tank in small portions, e.g. 1 US gal or 5 Liters at a time. Use the Universal DipStick to check the fuel level after each portion and write the summed up amount of fuel on the back of this scale card. Repeat until tank is completely fueled.