How does the APU fuel system ensure fuel supply?

• A. By using external fuel tanks
• B. Through a fully automatic system
• C. By manually adjusting fuel valves
• D. By relying on gravity feed

Answer: (B)

The APU fuel system ensures a consistent fuel supply through a fully automatic system. This automation is critical in maintaining the operational efficiency and reliability of the Auxiliary Power Unit (APU), which provides power for starting engines and operating electrical systems when the aircraft engines are not running. The fully automatic nature of the fuel system helps regulate fuel flow, monitor various parameters, and make adjustments as needed without requiring manual intervention. This capability minimizes the risk of human error and enhances the system's overall performance, ensuring that the APU can function smoothly and efficiently whenever needed.

Other methods like using external fuel tanks or gravity feed have their own applications but are not relevant to the APU's fuel system design which relies on automation. Manual adjustments, while sometimes used in different contexts, would not provide the level of reliability and efficiency achieved by an automatic system specifically designed for an APU's operational requirements.