What device ensures a minimum of a 15-second supply of fuel regardless of aircraft orientation?

The flip-flop valve is designed to maintain a minimum supply of fuel for the engine regardless of the aircraft's orientation. This is crucial for ensuring that the engine receives adequate fuel during dynamic maneuvers or changes in pitch and roll, which could cause fuel to slosh away from the fuel pumps.

The flip-flop valve works by allowing fuel to flow from the tank to the engine while preventing the fuel supply from being interrupted in various attitudes. This ensures that there is a continuous supply of fuel, effectively maintaining engine operation even in challenging conditions where fuel might not otherwise reach the pumps.

Other devices mentioned, such as the electric boost pump, primary jet pump, and wing tank flapper valve, play important roles in the fuel system but do not specifically guarantee a continuous fuel supply for at least 15 seconds irrespective of the aircraft's position. The electric boost pump assists in fuel delivery when needed, the primary jet pump relies on fuel flow to function, and the wing tank flapper valve aids in maintaining fuel levels but does not provide the same assurance of supply stability in all orientations as the flip-flop valve does.