At a cabin pressure altitude of 12,500 feet, what happens?

At a cabin pressure altitude of 12,500 feet, the situation becomes critical for cabin pressure management in an aircraft. When the cabin altitude reaches this level, the system is designed to alert the crew that the cabin altitude has exceeded a safe threshold. This alert is communicated through the Cabin Alt High CAS (Crew Alerting System) message, which warns the pilots that they need to take action to ensure passenger safety.

This alert is significant because above 12,500 feet, the risk of hypoxia increases for unprotected passengers, necessitating either the use of supplemental oxygen or a reduction in altitude to maintain flight safety. Recognizing this alarm enables the crew to promptly address the issue, either by descending to a lower altitude or activating supplemental oxygen systems to safeguard the health and safety of everyone onboard. This proactive approach is crucial in maintaining a safe flying environment.

While other scenarios, such as stabilization of cabin pressure or deployment of oxygen masks, may occur in certain circumstances, they are contingent upon the specific situation following the initial alert of cabin altitude exceeding the critical level.