What is the maximum normal APU ITT limit for 1 second?

The maximum normal APU ITT (Inter-Turbine Temperature) limit for 1 second is 820°C. This limit is critical for ensuring the safe operation of the Auxiliary Power Unit (APU) in the Dassault Falcon 7X. The APU provides electrical power and pneumatic pressure, which is essential for starting the main engines and for other auxiliary systems when the aircraft is on the ground or in flight.

Maintaining the APU ITT within specified limits is crucial to prevent damage to the engine components and to ensure longevity and reliability of the APU. Operating above this temperature threshold, even for a short duration, can lead to significant thermal stress and potential failure of the engine parts, particularly affecting the turbine.

The specified limit of 820°C reflects a careful balance between performance needs and safety considerations. In contrast, temperatures rising to 900°C or higher would significantly increase the risk of thermal damage, which is why they exceed the permissible limit. Thus, adherence to the specified 820°C limit for short-duration situations is essential for maintaining operational integrity and safety.