In AUTO mode, which component typically controls cabin differential pressure?

The outflow valve is the correct component that controls cabin differential pressure in AUTO mode. In this system, the outflow valve adjusts its position automatically to maintain the desired cabin pressure during flight. This adjustment is based on inputs from various sensors and control systems designed to monitor the cabin pressure relative to the outside atmospheric pressure.

When the aircraft climbs or descends, the atmosphere outside the aircraft changes, impacting cabin pressure. The outflow valve responds to these changes by modulating its opening to either release cabin air when the pressure is too high or to close slightly to maintain pressure when it is too low. This automatic adjustment is crucial for passenger comfort and safety, as it ensures that the cabin altitude remains within safe limits throughout the flight.

Other components like the safety valve, inlet valve, and extract valve play different roles in the pressurization and air circulation systems but do not directly control cabin differential pressure like the outflow valve does. The safety valve, for instance, serves as a backup mechanism to prevent excessive pressure buildup, while the inlet and extract valves are involved in regulating air intake and exhaust, contributing to overall cabin air quality and pressurization indirectly.