What action is required when the cabin altitude is above 12,500 feet?

When the cabin altitude exceeds 12,500 feet, the use of emergency oxygen regulators is essential to ensure the safety of personnel onboard. At these elevations, the risk of hypoxia increases significantly due to the lower partial pressure of oxygen in the atmosphere. Emergency oxygen regulators provide the necessary supplemental oxygen to maintain adequate oxygen levels, allowing crew members to function effectively and respond to any in-flight emergencies.

Activating emergency oxygen is a critical safety protocol designed to mitigate the risks associated with high cabin altitudes. It ensures that, in the event of cabin depressurization or oxygen depletion, the crew can continue to operate the aircraft safely.

Other actions, such as initiating a rapid descent or activating manual pressurization, may also be appropriate under certain circumstances but are not directly mandated solely based on cabin altitude exceeding 12,500 feet. Similarly, notifying air traffic control can be important for maintaining situational awareness and managing flight operations, but it does not directly address the immediate need for oxygen in this scenario. Therefore, using emergency oxygen regulators is the specific requirement in the context of elevated cabin altitude.