During aircraft refueling in a Type 4 system, under what conditions does only the lead pump continue running?

In a Type 4 refueling system, the operational dynamics dictate that the lead pump continues to run under specific flow rate conditions. The correct answer indicates the situation where the lead pump operates at a higher flow rate while the other pumps are effectively managed to ensure a consistent and safe flow of fuel.

When the lead pump is configured to continue running at 600 gpm while dealing with more than 40 gpm from other pumps, it allows for efficient fuel distribution while maintaining pressure and flow stability in the system. This scenario is crucial to ensure that adequate fuel is delivered to the aircraft without compromising safety or efficiency.

The synergy created by these flow conditions enables the system to handle varying demands effectively, ensuring that the lead pump can take on the primary responsibility of fuel delivery, while any additional flow, surplus to the lead pump’s output, is distributed by the auxiliary pumps, which can be shut off or modulated as necessary.

This knowledge is vital in maintaining the operational efficiency of aircraft refueling, as well as ensuring compliance with safety protocols during the refueling process.