What is the first step if electrical power must be powered down?

If electrical power needs to be powered down, the first step is to follow the Leaving the Airplane Checklist. This checklist is designed to ensure that all necessary safety protocols are followed when deactivating systems or exiting the aircraft. It includes steps to properly secure the aircraft, which is critical for ensuring safety and preventing any potential hazards that could occur due to unmonitored systems.

This procedure addresses several important aspects of power down, such as verifying the status of the systems and ensuring that all crew members are informed and accounted for in the process. Proper adherence to the checklist helps mitigate any risks associated with the electrical systems being turned off, as it organizes the steps required for a thorough and safe power down operation.

In contrast, the other options involve specific actions that occur after the initial notification and securing of the aircraft. Utilizing the Safety and Power Up Checklist is useful for startup rather than shutdown procedures, while turning off all circuit breakers or notifying the flight crew follows the established protocols but is not the leading action in the process of powering down the electrical systems.