What type of fuel is considered when computing the empty weight and corresponding center of gravity (CG) of an aircraft?

When computing the empty weight and the corresponding center of gravity (CG) of an aircraft, unusable fuel is considered because it is the fuel that cannot be used during normal operation. Unusable fuel must remain in the tanks for operational safety and structural integrity, thus it effectively adds weight to the aircraft even though it cannot contribute to flight performance.

In the context of weight and balance calculations, it’s crucial to account for all components of weight that will affect the aircraft's performance and safety, including any unusable fuel that is always present. This is different from usable fuel, which the aircraft can actually burn; full fuel and reserve fuel considerations also focus on operational scenarios rather than the static calculations for empty weight and empty CG. Therefore, the presence of unusable fuel is essential in establishing an accurate empty weight and center of gravity for the aircraft.