What role do flapper valves serve in aircraft fuel tanks?

Flapper valves in aircraft fuel tanks primarily function as check valves. Their key role is to allow fuel to flow in one direction while preventing backflow, thereby ensuring that fuel moves towards the engine without being pushed back into the tank. This is crucial in maintaining the efficiency of the fuel system and preventing fuel starvation to the engine, which can occur if fuel attempts to flow backward due to changes in pressure or movement of the aircraft.

While it is true that flapper valves help to prevent backflow of fuel, their specific design and operation classify them more distinctly as check valves. Check valves are devices that permit the flow of fluid in one direction only, and flapper valves are a type of check valve utilized in fuel systems for this purpose.

Understanding the function of flapper valves in this context highlights the importance of their role in maintaining the integrity and performance of the aircraft's fuel system, contributing to the overall safety and reliability of flight operations.