Why are turbine inlet temperatures monitored, and what do ITT or EGT gauges indicate?

• A. They indicate turbine blade health and engine stress; approaching limits signals a potential problem; monitor for safe operation.
• B. They measure cabin temperature.
• C. They indicate fuel flow rate.
• D. They monitor hydraulic pressure in lines.

Answer: (A)

Turbine inlet temperatures are monitored because they show the heat load the turbine blades must withstand during operation, which directly affects blade life and overall engine safety. ITT (inter-turbine temperature) or EGT (exhaust gas temperature) gauges indicate how hot the gas is at critical points in the engine flow. ITT reflects the temperature of gases entering the turbine and is a direct indicator of the thermal stress on the turbine stage; EGT shows the temperature of the exhaust after combustion, which relates to combustion efficiency and the engine’s thermal state. If these temperatures approach their limits, it signals that the engine is under excessive thermal stress or that the fuel control may be delivering too much fuel, risking damage or failure, so operators can take appropriate corrective action to maintain safe operation. These gauges are not measurements of cabin temperature, fuel flow rate, or hydraulic pressure.