What is the APU Exhaust Gas Temperature (EGT) limit during start?

The APU Exhaust Gas Temperature (EGT) limit during start is 1032°C, which is the correct answer. This limit is established to ensure the safe operation of the Auxiliary Power Unit (APU) during the critical phase of engine start-up. Exceeding this temperature can lead to potential damage or malfunction of the APU, which plays a crucial role in providing electrical and pneumatic power during ground operations.

Maintaining the EGT within the specified limit is essential because high temperatures can lead to thermal stresses and material fatigue in turbine components. This enforced threshold supports not just the longevity of the APU but also promotes safe overall aircraft operation. The other temperature choices fall below this critical maximum and do not align with the operational limits set for APU starts, indicating a lower tolerance for thermal management during this phase.