What is the startup sequence for the engines in the ERJ-145?

The startup sequence for the engines in the ERJ-145 begins with the activation of the Auxiliary Power Unit (APU), which provides the necessary electrical power and pneumatic air to start the engines. Once the APU is operational, the next step involves allowing fuel flow to the engines. This is crucial because the engines require fuel to start running after the ignition system is engaged. Following the establishment of proper fuel flow, the ignition system is then engaged to enable the combustion process within the engine.

This sequence is vital for ensuring a smooth and safe engine start, as it follows a logical flow that allows for the necessary preparations (like power and air) to be in place before the fuel and ignition sequence is initiated. By using the APU initially, the aircraft ensures that everything is primed for engine ignition, preventing potential issues that could arise from starting the engine without the proper support systems in place.