How does Battery 1 assist with starting the engine?

Battery 1 plays a crucial role in the engine starting process by energizing systems essential for a successful startup. During the engine start sequence, Battery 1 supplies power to the starter motor, which is responsible for turning the engine over until it starts. This essential function ensures that the engine achieves the necessary rotational speed to start combustion.

Once the engine has started and the generator begins to produce electrical power, the system on the aircraft can then manage the distribution of power between Battery 1 and Battery 2. Battery 1 is also involved in transitioning power to other systems, which may include providing assistance to Battery 2, especially during the initial phases immediately following engine start.

This aspect of Battery 1's function emphasizes its importance during the initial start-up phase, rather than being involved with powering non-essential systems, providing full power to the aircraft, or starting the generator itself, which relies on the engine to spin up first. Understanding this function helps in grasping how the electrical systems within the PC-12 NG interconnect and work together during critical operational phases.