What prevents fluid loss when the filter bowl and element are removed fom the f-16's?

When the filter bowl and element are removed from an F-16's fuel system, fluid loss is typically prevented by the presence of check valves and pressure maintenance systems that minimize fuel leakage. Additionally, the design of the fuel system includes features such as sealing surfaces and shut-off valves that activate during maintenance procedures. These mechanisms ensure that fuel does not escape, maintaining system integrity and safety during maintenance operations.