What action should be taken if the EGT exceeds 715°C during APU start?

When the Exhaust Gas Temperature (EGT) exceeds 715°C during APU start, terminating the start process immediately and troubleshooting is the appropriate action. This threshold indicates that the engine is experiencing a potentially dangerous over-temperature condition, which could lead to engine damage or failure if not addressed promptly.

Continuing with the start process under these circumstances would increase the risk of damage to the APU, as excessive temperatures can adversely affect engine components, leading to costly repairs or even catastrophic failure. By terminating the start, the situation can be assessed, allowing for troubleshooting and corrective action to be taken, ensuring the safety and reliability of the APU.

Addressing the issue promptly by troubleshooting can also help determine the cause of the over-temperature situation, whether it is due to fuel flow issues, malfunctioning sensors, or other potential factors. This proactive approach is essential in maintaining the proper functioning and longevity of the APU.