What is the appropriate action regarding oxygen masks in response to cockpit or cabin smoke/fire?

In the event of smoke or fire in the cockpit or cabin, the appropriate action is to don oxygen masks. This is crucial because the presence of smoke can quickly lead to diminished visibility and compromised oxygen levels, jeopardizing the safety of everyone on board. Using oxygen masks ensures that pilots and passengers have access to breathable air and helps maintain functionality in high-stress situations.

Wearing the masks allows the crew to continue flying and managing the aircraft while addressing the emergency. In addition, it provides the capability to communicate effectively with air traffic control and coordinate further actions, whether that means returning to an airport, preparing for a possible evacuation, or implementing other safety protocols.

While checking fuel flow, evacuating the aircraft, or reducing engine power may be relevant actions under different emergency scenarios, they do not directly address the immediate threat posed by smoke or fire, where the priority is to secure breathable air and stabilize the environment.