What is the first step in the engine start-up procedures?

The first step in the engine start-up procedures is to switch on the Master ON. This step is crucial as it initiates the electrical system of the engine and powers up essential components necessary for the starting sequence. By engaging the Master ON, the crew allows for the activation of systems that monitor the engine's operational readiness, including fuel delivery and ignition circuits. This systematic approach ensures that all systems are prepared before attempting to start the engine, ultimately fostering a safer and more efficient start-up process.

In the context of the overall procedure, making sure that the Master switch is activated first provides a logical foundation for subsequent steps, such as engaging the ignition and pressing the starter button. It is vital in a fire rescue setting to adhere to this sequence to prevent any complications or malfunctions that may arise from incorrect start-up procedures.