FAA Powerplant Written Practice Test

From what point on a turbine engine are measurements taken when trimming?

1. Fuel Injection Point

2. Compressor Inlet

3. Turbine Discharge Pressure Line

4. Exhaust Outlet

The correct answer is: Turbine Discharge Pressure Line

In the context of turbine engine performance and trimming, measurements are typically taken from the turbine discharge pressure line. This is because the turbine discharge represents the engine's performance after the combustion process and provides a reliable indication of the engine's thrust and efficiency. Trimming involves adjusting the engine to achieve optimal performance, and assessing the pressure in the discharge line allows technicians to monitor the engine’s operational characteristics and make necessary calibrations. This measurement accounts for various factors affecting performance, such as airflow and combustion efficiency, which are critical for maintaining the desired engine parameters. Other points like the fuel injection point and compressor inlet may relate to different aspects of engine performance but do not directly indicate the combustion efficiency or thrust output available at the turbine discharge. Similarly, measuring at the exhaust outlet can provide some information about engine performance but is less relevant for trimming as it does not focus specifically on the pressure after the turbine, where the effects of combustion are fully realized.