When weighing an aircraft with full fuel tanks, which fuel weight is not subtracted from the scale readings?

When weighing an aircraft with full fuel tanks, which fuel weight is not subtracted from the scale readings?

• A. Usable fuel
• B. Residual fuel
• C. Unusable fuel
• D. Fuel in the tanks

Answer: (C)

When determining the aircraft’s empty weight by weighing with full tanks, you subtract only the fuel that can be removed from the aircraft in normal operation. That means you subtract usable fuel, since it’s fuel you would burn and not part of the empty weight. The fuel that cannot be pumped out remains with the aircraft no matter what, so it is not subtracted. This unrecoverable portion is the unusable fuel, and it must stay in the weight calculation. So, the fuel that is not subtracted from the scale readings is the unusable fuel because it cannot be drained and is part of the aircraft’s weight even when tanks are effectively empty.

When determining the aircraft’s empty weight by weighing with full tanks, you subtract only the fuel that can be removed from the aircraft in normal operation. That means you subtract usable fuel, since it’s fuel you would burn and not part of the empty weight. The fuel that cannot be pumped out remains with the aircraft no matter what, so it is not subtracted. This unrecoverable portion is the unusable fuel, and it must stay in the weight calculation.

So, the fuel that is not subtracted from the scale readings is the unusable fuel because it cannot be drained and is part of the aircraft’s weight even when tanks are effectively empty.