FAA Powerplant Written Practice Test

Which instrument should be monitored to minimize the possibility of a "hot" start in a gas turbine engine?

1. Oil pressure

2. Tachometer

3. Fuel flow rate

4. Turbine inlet temperature

The correct answer is: Turbine inlet temperature

Monitoring the turbine inlet temperature is crucial to minimizing the risk of a "hot" start in a gas turbine engine. A "hot" start occurs when the temperature within the combustion section of the engine exceeds acceptable limits during the engine start sequence. This condition can result from excessive fuel flow or inadequate airflow into the engine, leading to a rapid rise in temperature. The turbine inlet temperature gauge provides real-time feedback on the temperature at the entry point of the turbine section. By closely watching this instrument during start-up, operators can identify any abnormal temperature increases early in the starting process. If the turbine inlet temperature begins to rise too quickly or exceeds the manufacturer's specified limits, corrective actions can be taken, such as advancing the throttle or shutting down the engine, to prevent damage and unsafe operating conditions. Other instruments, while important for the operation of the engine, do not provide the same direct correlation to hot start conditions as the turbine inlet temperature does. This makes the turbine inlet temperature the primary gauge for ensuring the engine starts safely and efficiently without entering a potentially damaging hot start scenario.