After which action is the briefing most effectively communicated?

The briefing is most effectively communicated after the relieving specialist indicates that the preview has been completed because this moment signifies that the prior controller has fully transitioned all necessary information regarding current air traffic and sector status to the new controller. This ensures that the new controller has the most up-to-date and comprehensive understanding of the operational situation they are about to manage.

This timing allows for an immediate and focused briefing where the new controller can ask questions and clarify any uncertainties directly after receiving the relevant information. The effectiveness of this approach lies in its ability to provide seamless continuity of operations, which is crucial for maintaining safety and efficiency in air traffic management.

In contrast, breaks, reviewing previous notes, or the lunch hour may create distractions or lead to attention lapses, thereby reducing the effectiveness of the briefing. These moments do not guarantee the most effective communication of current operational details as seen in the case where the preview is definitively acknowledged as complete.