For turbine engine fueling systems that use pressure fueling, what pressures must be specified near the fuel filler?

• A. Maximum fueling supply pressure and maximum defueling pressure
• B. Maximum defueling pressure only
• C. Minimum fueling pressure
• D. No pressure specification

Answer: (A)

In pressure fueling, it's essential to control the pressure that can be applied to the fuel system, especially at the filler location. Specifying the maximum fueling supply pressure ensures the fueling source cannot push more pressure into the tank than the system was designed to handle, protecting tanks, hoses, fittings, and the venting system from overpressure and potential leaks or ruptures. Including the maximum defueling pressure covers the opposite flow direction, preventing dangerous surges or backpressure when fuel is being removed and ensuring safe operation during defueling. Together, these two limits provide clear, safety-focused guidance for both fueling and defueling operations right at the filler.

Inevitably, leaving out one of these pressures or claiming only a minimum or no specification would fail to address the real safety concerns: the system could be overpressurized during fueling or subjected to hazardous conditions during defueling.