What purpose does a sump box serve in an aircraft's fuel system?

The correct purpose of a sump box in an aircraft's fuel system relates to its function of collecting and ensuring a steady supply of fuel for various operations, including feeding the fuel boost pump. The sump box allows for fuel to be collected from different parts of the fuel system, which is particularly beneficial during changes in altitude, pitch, or roll that an aircraft may experience during flight. This consistent supply is crucial for maintaining engine performance and ensuring that the fuel pumps can operate without interruption, regardless of the aircraft's orientation.

In contrast, while preventing fuel contamination is an important function of various components within the fuel system, this is not the primary function of the sump box. Similarly, the idea of storing excess fuel is more characteristic of larger fuel tanks or reserve systems rather than the sump box, which is designed to facilitate the immediate operational dynamics of fuel delivery. Regulation of fuel temperature is managed by different components, such as heat exchangers, rather than by the sump box itself. Therefore, the primary role of the sump box is to ensure the boost pump has guaranteed access to fuel, which is vital for sustaining engine operation during varying flight conditions.