What is the first step aircrew members should take in response to unexpected mission changes?

The first step aircrew members should take in response to unexpected mission changes is to remain calm. This is crucial because maintaining composure allows the crew to assess the situation objectively and make rational decisions. A calm demeanor is essential in high-pressure scenarios, as it sets the tone for team communication and coordination during a crisis.

When aircrew members stay calm, they are better equipped to process information, communicate effectively, and prioritize next steps, which might involve notifying ground control, determining the need for additional resources, or discussing potential changes to the flight route. Each of these actions can follow more effectively when the crew is not overwhelmed by stress or anxiety. Therefore, remaining calm serves as a foundational step that enables the crew to respond appropriately and efficiently to unexpected changes.