During what portion of the fueling operation should the fueling control valve be held open?

The fueling control valve should be held open the entire time during the fueling operation to ensure a consistent and controlled flow of fuel into the aircraft. Maintaining this position allows for safety and efficiency, as the valve's closure would disrupt the fueling process, leading to potential hazards such as fuel spills or misfueling. With the valve open during the entire operation, it allows the fuel supplier and ground crew to monitor the flow and make necessary adjustments, ensuring the aircraft is adequately fueled while adhering to safety protocols.

Using the fueling control valve in this manner helps to prevent complications that could arise if the valve were closed at any point, such as creating pressure imbalances or interruptions in flow that could lead to equipment damage or safety risks. Maintaining the valve's open position throughout the fueling process also supports proper communication between the fueling team and personnel involved in aircraft operations, ensuring everyone is aware of the fueling status and can respond appropriately if issues arise.