Which memory item requires alerting the crew during an emergency?

The requirement to don oxygen masks during an emergency is critical because it ensures that the crew and passengers maintain adequate levels of oxygen in situations where cabin pressure may be compromised. This action is crucial not only for the safety of the crew but also for the ability to effectively operate the aircraft. Alerting the crew serves to ensure everyone is aware of the emergency and can take immediate action to secure their own oxygen supply while also being prepared to assist others.

In many emergencies, particularly those involving rapid decompression or smoke in the cockpit, having oxygen available allows the crew to maintain situational awareness and make critical decisions. This memory item emphasizes teamwork and communication among the crew, which is vital in high-stress situations. Therefore, alerting the crew as part of donning oxygen is essential for ensuring a coordinated and safe response to the emergency.