Distinguish between ITT and EGT in terms of measurement location and use.

• A. ITT is measured in exhaust; EGT inside turbine; ITT for exhaust limits
• B. ITT is measured in hot section inside turbine; EGT measured in exhaust; ITT used for start/run limits, EGT for exhaust health
• C. ITT and EGT are the same measurement
• D. ITT is measured after cool-down; EGT before start

Answer: (B)

The main idea is where the temperature is measured and what that measurement is used for in protecting and monitoring the engine.

Inter Turbine Temperature is the temperature of the hot gas inside the turbine section, typically at or just before the turbine inlet. This location directly reflects the heat the turbine blades will experience, so it’s the critical value used to set start and run limits. Keeping ITT within limits protects the turbine blades from thermal damage as fuel flow and air flow change during start, acceleration, and steady operation.

Exhaust Gas Temperature is measured in the exhaust stream after the turbine. It serves as a broader indicator of combustion efficiency and overall exhaust health. High or out-of-spec EGT can point to issues with fuel-air mixture, combustion stability, or downstream components, but it’s not the primary blade temperature limit like ITT.

So, ITT is measured in the hot section inside the turbine and used for start/run limits, while EGT is measured in the exhaust and used to monitor exhaust health and combustion performance.