FAA Powerplant Written Practice Test

What is the correct starting sequence of a turbojet engine?

1. Ignition, fuel, starter

2. Fuel, starter, ignition

3. Starter, ignition, fuel

4. Starter, fuel, ignition

The correct answer is: Starter, ignition, fuel

When starting a turbojet engine, the correct sequence begins with engaging the starter. The starter is responsible for initiating the engine's rotation and creating the airflow necessary for combustion. After the engine reaches a certain speed and conditions are favorable, ignition is introduced to ignite the fuel-air mixture in the combustion chamber. This is crucial as ignition must occur at the right moment to ensure that combustion begins efficiently and safely. Following the ignition, fuel is supplied to sustain the combustion process, leading to normal engine operation. In this sequence, ensuring that the starter activates first is vital because it prepares the engine for ignition. Ignition is needed to initiate combustion, while fuel is necessary to maintain that combustion once it's started. Understanding this sequential progression helps in grasping the operational startup procedures of turbojet engines.