What is announced on the 1MC when the CO arrives?

When the Commanding Officer (CO) arrives, it is a significant moment that is traditionally recognized by announcing "Arleigh Burke Arriving" over the 1MC, which is the ship's internal communications system. This announcement serves both a formal and ceremonial purpose, marking the presence of the CO onboard and fostering a sense of respect and protocol among the crew. It is essential for maintaining good order and discipline, as the ship's personnel are always mindful of the CO's authority and importance in naval operations. Additionally, recognizing the arrival of the CO reinforces the hierarchical structure of command within the Navy, reminding everyone of the leadership and responsibilities that come with the position.

Other options, while they may seem relevant, are not traditionally used for this specific announcement. Using phrases like "New Commander Onboard" does not accurately reflect the specific context of the arrival of the CO in that moment, and the mention of "Arleigh Burke Departing" would be appropriate for a different scenario altogether. This distinction highlights the importance of proper naval communication protocol.