What is the minimum fuel requirement for APU operation?

The minimum fuel requirement for APU operation is 2,000 pounds. This figure is crucial for ensuring that the Auxiliary Power Unit (APU) functions optimally during its operation. The APU serves as a power source for the aircraft when the engines are not running, providing electrical power and pneumatic pressure for starting the engines and for environmental control systems. Having a minimum fuel reserve allows for uninterrupted operation of the APU, facilitating essential systems that are vital for the aircraft's functionality, particularly during pre-flight checks and ground operations.

A lower fuel level than the minimum requirement could lead to system malfunctions or inadequate power for engine start procedures, thus jeopardizing mission readiness and safety. Therefore, adhering to the 2,000-pound minimum ensures that the APU can operate efficiently without risk of fuel starvation.