FAA Powerplant Written Practice Test

What is a correct statement regarding the ignition system of a turbine engine?

1. The system remains energized during flight

2. It is normally off once the engine starts

3. It causes high-voltage losses

4. It requires constant manual adjustment

The correct answer is: It is normally off once the engine starts

The ignition system of a turbine engine is typically designed to function only during the engine start phase and is normally turned off once the engine is running stably and producing sufficient airflow and combustion. This is because the ignition is only necessary to establish combustion at engine start; once the engine is operating normally, the combustion process is self-sustaining due to the high temperatures and pressures present in a turbine engine. In turbine engines, the ignition system is critical during start-up but not needed continuously during operation, as the combustion process relies on the engine's design to maintain the necessary fuel-air mixture and conditions for ongoing combustion. This characteristic of the system underscores its functionality strictly for start-up and transitional operations.