What is the purpose of the check valves installed in the motive flow line?

The purpose of the check valves installed in the motive flow line is to stop fuel flow between the left and right wing tanks. In the design of fuel systems for aircraft like the Pilatus PC-12 NG, check valves are strategically placed to ensure that fuel can move in one direction while preventing backflow. This is crucial for maintaining the integrity of the fuel supply to the engine and ensuring that fuel is utilized efficiently without mixing between the tanks.

By preventing fuel from flowing between the left and right tanks, the check valves help avoid imbalances that could affect the aircraft's weight and balance, which is vital for safe operation. This design feature ensures that each tank can be managed independently, allowing for better control during flight operations and enabling pilots to manage fuel reserves effectively without concern for unwanted cross-flow.