How many gallons of fuel are stated as usable in the aircraft?

The statement that 40 gallons of fuel are usable in the aircraft is based on the manufacturer's specifications, which indicate the amount of fuel that can be safely utilized during flight operations. This figure is important for planning purposes, as it directly affects the aircraft's range, endurance, and weight and balance calculations.

In aviation, not all fuel within a tank is considered usable due to factors like the design of the fuel system and the location of fuel pickup points. Fuel that cannot be accessed or used by the engine, due to those design limitations, may remain in the tank but can't be drawn into the engine under normal operating conditions.

Understanding the usable fuel quantity helps pilots make informed decisions about flight planning, ensuring they do not exceed weight limitations and that they have enough fuel to complete their intended flight. Accurate knowledge of usable fuel is essential for calculating endurance and determining how much weight can be added, including passengers and cargo, without compromising safety.