What is a common indicator of needing APU maintenance?

A common indicator of needing APU maintenance is the presence of unexpected system alerts. These alerts often serve as an early warning system, indicating that the APU is experiencing issues or may be operating outside of its normal parameters. When the APU is functioning properly, you typically wouldn't see alerts; therefore, unexpected alerts can point to problems requiring immediate attention to ensure the APU continues to operate effectively and safely.

Monitoring these alerts is crucial for the maintenance team, as they can help diagnose issues before they escalate into more significant problems. Regular attention to system alerts can help maintain the reliability and efficiency of APU operations, preventing potential breakdowns and costly repairs.