What is the function of the primary outflow valve?

The primary outflow valve plays a crucial role in managing cabin pressure within an aircraft. Its main function is to regulate the amount of air that exits the pressurized cabin. By doing so, the valve either retains cabin pressure during climbs and descents or allows for controlled release of that pressure, ensuring that the cabin environment remains safe and comfortable for passengers and crew.

When the aircraft climbs, the outflow valve typically remains closed to maintain cabin pressure. Conversely, during descent, the valve opens to allow air to escape, thus managing the pressure differential. This is essential for passenger comfort and safety, as rapid changes in pressure can lead to discomfort or potential harm.

By allowing the control of cabin pressure based on operational needs, the primary outflow valve is integral in enabling the aircraft to maintain safe and suitable living conditions as it varies in altitude.