FAA Powerplant Written Practice Test

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

1. Fuel flow gauge

2. Exhaust gas temperature gauge

3. Turbine inlet temperature

4. Compressor pressure ratio

The correct answer is: Turbine inlet temperature

Monitoring the turbine inlet temperature is crucial in minimizing the possibility of a "hot" start in a gas turbine engine because this temperature gives a direct indication of the thermal condition of the engine as it initiates the start sequence. A "hot" start occurs when the engine experiences excessive temperature during the start cycle, which can lead to potential damage or failure. The turbine inlet temperature reflects the heat being generated during the combustion process and can indicate if fuel flow and airflow are appropriately balanced to ensure stable ignition and operation. By keeping an eye on this gauge, operators can adjust fuel flow or engine operation to avoid temperatures that may exceed the engine's design limits. Other instruments like the fuel flow gauge or exhaust gas temperature gauge provide indirect information. While they are important for general engine monitoring, the turbine inlet temperature is the most critical for avoiding dangerous startup conditions. The compressor pressure ratio indicates engine performance but does not directly relate to the thermal risks present at startup.