What automatic response occurs if the APU detects an overheating condition?

When the Auxiliary Power Unit (APU) detects an overheating condition, it triggers an automatic shut-off to protect the system from damage. This response is critical because an overheating APU can lead to severe mechanical failure or even fire, so the safety protocol is designed to immediately stop the operation. By shutting down, the APU prevents the escalation of the overheating issue, safeguarding both the equipment and personnel.

The other responses highlight actions that do not align with the safety and operational principles of the APU. For instance, increasing engine power would exacerbate the overheating problem rather than mitigate it. Similarly, sending a maintenance alert may be necessary, but it is not an immediate response to an overheating situation. Lowering the fuel supply might be a potential corrective action, but it does not directly address the critical need for immediate shutdown when overheating is detected.