FAA Powerplant Written Practice Test

What is the proper starting sequence for a turbojet engine?

1. Ignition, starter, fuel

2. Starter, fuel, ignition

3. Starter, ignition, fuel

4. Fuel, starter, ignition

The correct answer is: Starter, ignition, fuel

The proper starting sequence for a turbojet engine begins with engaging the starter, followed by ignition, and then introducing fuel. Starting with the starter is essential because it initiates the rotation of the engine's turbine and compressor sections, generating airflow necessary for the combustion process. Once the engine has reached a sufficient speed, ignition can be activated. This ensures that a spark is introduced at the right moment, allowing the fuel-air mixture to ignite effectively. Introducing fuel after the ignition is initiated prevents flooding of the combustion chamber with unburned fuel, ensuring a more stable and controlled start-up process. By following this sequence, operators facilitate a smooth start-up of the engine, minimizing the risk of issues like back-firing or compressor stalls that could occur if fuel is introduced prematurely or if the engine is not yet capable of sustaining combustion. This is a critical sequence taught during pilot and technician training for turbojet engines, ensuring optimal performance and safety during engine start.