The flight crew can set the cabin pressurization system to operate in automatic, semi-automatic, or manual modes.

Automatic Operation

In normal operation, cabin pressurization is fully automatic. The flight crew monitors the system but does not need to control it. The cabin air pressure follows schedules provided by the FMGS.

• If FMGS data is unavailable for automatic pressurization, the crew only needs to select the landing field elevation. This is known as semi-automatic mode.
• The pressurization controller normally uses the landing elevation, QNH from the FMGC, and the pressure altitude from ADIRS.
• If FMGC data is unavailable, the controller will use the captain’s BARO reference from ADIRS and the LDG ELEV selection.

Manual Operation

In manual mode, the flight crew directly controls the cabin altitude by adjusting the manual motor of the outflow valves using the controls on the pressurization control panel.

Controller Operation

• When the system is in automatic or semi-automatic mode, one controller is active while the other remains on standby.
• In automatic mode, the active controller signals the position of the valve to the ECAM.

LDG ELEV FAULT

An LDG ELEV FAULT occurs when FMGS landing elevation data is unavailable.