ITT must be below what temperature before attempting a ground start?

• A. 90°C
• B. 100°C
• C. 110°C
• D. 120°C

Answer: (D)

The test focuses on when it’s safe to attempt a ground start by allowing the engine’s hot section to cool enough. ITT, or Inter-Turbine Temperature, gauges how hot the core is after shutdown. If it’s still too hot, starting can cause a hot start, putting great thermal stress on components like blades and bearings and increasing the risk of damage or failed ignition.

120°C is the chosen safe threshold. It gives a practical cooling limit: it isn’t so low that you’d wait unnecessarily long, but it isn’t high enough to risk a hot start once you reintroduce fuel and ignition. At or below this temperature, the engine’s core is cooled sufficiently to start without subjecting the hot section to excessive thermal stress.

The other numbers aren’t the manufacturer’s required limit for a ground start, so they wouldn’t provide the same protection against hot starts.