What is the primary function of main tanks in an aircraft's fuel system?

The primary function of main tanks in an aircraft's fuel system is to supply fuel for its related engine. The main tanks are essential because they hold the bulk of the fuel needed for the aircraft's operation and provide a direct fuel source to the engines under normal operating conditions. This design ensures that the engines receive a continuous and sufficient flow of fuel, which is crucial for maintaining thrust and overall performance during flight.

Auxiliary tanks, external tanks, and emergency fuel storage have different roles within the overall fuel management system. Auxiliary tanks are used to increase the aircraft's range by providing additional fuel, while external tanks are typically added for particular missions to extend flight time. The concept of storing fuel for emergency use refers to contingency planning rather than a primary function of the main tanks, which align with the operational needs of the aircraft during regular flight.