Which valve provides manual cabin pressure control?

• A. Automatic pressure controller valve
• B. MAN PRESS CONT valve located on the bottom left of the copilot's instrument panel
• C. Vent control valve on overhead panel
• D. Cabin pressure selector valve on pilot's panel

Answer: (B)

Manual cabin pressure control is provided by a dedicated valve that lets the crew override the automatic system and set the cabin pressure directly. This manual pressure control valve, located on the bottom left of the copilot’s instrument panel, is the interface used when you want to bypass the automatic pressure controller and command a specific pressure level or cabin altitude. The automatic pressure controller valve handles automatic regulation by maintaining the programmed cabin pressure through the outflow valve, so it isn’t used for direct manual setting. The vent control valve on the overhead panel manages ventilation flow rather than the pressurization setpoint, and the cabin pressure selector valve on the pilot’s panel isn’t the manual override used for direct control.