What is the function of annunciators in the CSOSS sequencing process?

• A. They signal the crew to rotate.
• B. They log events for later review.
• C. They calibrate sensors.
• D. They signal status and facilitate transitions through planning, command, and execution phases.

Answer: (D)

Annunciators provide real-time status signals that guide the flow of the sequencing process. In CSOSS sequencing, they show whether a step is ready to begin, when a phase is completed, or when an action is required due to an abnormal condition. This gives the crew a clear, shared understanding of where the plan stands and what comes next, helping to synchronize planning, command, and execution so transitions between phases happen smoothly and safely. They aren’t used to rotate personnel, log events for later review, or calibrate sensors—their primary role is immediate status signaling and facilitating the right transitions at the right time.