What is the first action in the depressurization memory items?

The first action in the depressurization memory items is to don oxygen. When an aircraft experiences a depressurization event, the immediate risk to crew and passengers is hypoxia due to the decreased availability of oxygen at altitude. By putting on oxygen masks as the initial response, individuals can quickly secure an adequate supply of oxygen, which is critical for maintaining consciousness and ensuring safety.

The subsequent actions, although important, are secondary to the immediate need for oxygen. Alerting other crew members, activating emergency beacons, and notifying the command center are all necessary steps, but they can only be effectively carried out once the immediate physiological need for supplemental oxygen is addressed. By prioritizing oxygen, the crew ensures that everyone can function and respond effectively to the emergency.