ITT must be below what temperature before attempting an air start?

• A. 120°C
• B. 90°C
• C. 80°C
• D. 100°C

Answer: (B)

The main idea is safety during an air start: you don’t want to start the engine when it’s still too hot, because residual heat can cause thermal damage as rotation is brought up and fuel is reintroduced. Inter-Turbine Temperature (ITT) measures how hot the turbine sections are. If ITT is above a safe level, starting with air could push temperatures into a range that risks blade distortion, bearing damage, or hot spots in the combustor.

The necessary threshold here is 90°C. Keeping ITT below this limit before attempting an air start provides enough cooling margin to handle the start transient without overheating critical components. Numbers higher than that (like 100°C or 120°C) would tolerate too much heat and raise the risk of damage, while a value like 80°C, though even safer, is not the published limit for this procedure.