How do cabin pressure controllers manage cabin pressure in automatic mode?

Cabin pressure controllers in automatic mode primarily utilize a system of redundant digital pressure controllers to manage the cabin pressure effectively. These digital controllers continuously monitor the internal cabin pressure and make real-time adjustments to the outflow valves to maintain the desired pressure levels. The redundancy in the system ensures reliability and safety, as if one controller fails, the other can take over to maintain proper cabin pressure.

This method allows for precise control and adjustments without requiring manual intervention, which is crucial during various phases of flight, especially during ascent and descent. By leveraging technology, these systems optimize passenger comfort and safety by managing the rate of pressure change in relation to external atmospheric conditions.

While external atmospheric conditions do play a role in how pressure is managed, they are not directly used to adjust the cabin pressure in automatic mode. Monitoring oxygen levels or manually adjusting the outflow valve would also not be functions of an automatic system, highlighting the advantages of using a redundant digital pressure control approach for efficiency and reliability.