What is the maximum ITT at fuel introduction?

The maximum Interstage Turbine Temperature (ITT) at fuel introduction is indeed at 150ºC. This temperature represents a critical limit for safe operations in turbofan engines, specifically during the fuel introduction phase, where it ensures that the engine components are not subjected to excessive thermal stress which could lead to operational issues or engine failure.

Maintaining the ITT at or below this threshold during fuel introduction helps to ensure combustion stability and efficiency, thereby reducing the risk of engine damage. Elevated temperatures beyond the recommended limit can result in hot streaks or damage to the turbine blades and other engine components, ultimately affecting performance and safety.

In the context of the other options, while temperatures like 850ºC, 870ºC, and 1000ºC may represent operational limits at other phases or under different conditions, they exceed the necessary threshold for fuel introduction. Therefore, they are not appropriate choices for the temperature at which fuel induction may safely occur.