Fuel gravity feed tanks have what gallon capacity?

• A. 1,200 GAL
• B. 200 GAL
• C. 600 GAL
• D. 1,500 GAL

Answer: (C)

Gravity feed fuel tanks are sized to provide a dependable fuel head to the engine fuel system, using the weight of the fuel to push it toward the pumps even if other supply isn’t active. The capacity must be enough to cover engine demand during normal operation and provide a reasonable reserve without adding unnecessary weight.

Six hundred gallons is a practical balance: it gives a sufficient volume to maintain gravity-driven flow and keep the system fed under typical high-demand conditions, while not adding excessive weight or space requirements. Smaller capacities, like two hundred gallons, would risk fuel starvation during high power or maneuvering, whereas much larger capacities, such as twelve hundred or fifteen hundred gallons, would impose unnecessary weight and complexity for most configurations.

So the 600-gallon rating reflects a mid-range, workable size for a gravity feed setup that prioritizes reliable delivery without overburdening the aircraft or system with extra weight.