How is cabin pressure typically controlled in a pressurized aircraft?

In pressurized aircraft, cabin pressure is typically controlled using an automatic outflow valve. This system is designed to maintain the desired cabin pressure during various phases of flight. The automatic outflow valve operates in conjunction with sensors that monitor cabin altitude and pressure, allowing the valve to adjust automatically based on the aircraft's altitude, ensuring a comfortable environment for passengers and crew.

The advantage of this automatic mechanism is that it reacts rapidly to changes in altitude, optimizing cabin pressure without requiring constant manual input from the flight crew. This is particularly crucial during ascent and descent, where pressure changes occur quickly. Additionally, the automatic system can help prevent over-pressurization or depressurization, which could pose safety risks.

In contrast, while a manual outflow valve allows for human control of the cabin pressure, it relies on the crew's intervention and can increase the risk of error. Pressure relief valves and cabin altitude regulators serve different specific functions in the overall pressure control system, further illustrating why the automatic outflow valve is the most effective and commonly used method for managing cabin pressure in pressurized aircraft.