Which switch is responsible for opening the pressurization control valve and closing the defog valve?

The DUMP switch is specifically designed to manage cabin pressure and environmental control systems by opening the pressurization control valve and closing the defog valve. This action is crucial during certain operational scenarios, such as when the aircraft needs to rapidly adjust cabin pressure or during a change in altitude where moisture or fogging could become an issue. The opening of the pressurization control valve allows for the release of cabin pressure, which helps stabilize environmental conditions. Meanwhile, closing the defog valve prevents warm, moist air from entering areas where it could cause fogging, enhancing visibility and comfort in the cockpit and cabin. Understanding the function of the DUMP switch in this context highlights its critical role in maintaining proper cabin pressure architecture and overall flight safety and comfort.