What happens when the ON position is selected for the BAG VENT switch?

When the BAG VENT switch is selected to the ON position, the bag vent valve opens. This action allows for proper venting of the bag compartments in the aircraft, which is critical for maintaining cabin pressure and ensuring the safety of both passengers and crew. By opening the bag vent valve, any excess pressure that may have built up can be released, thus promoting a stable cabin environment. Proper understanding of this function is vital for anyone operating or managing the aircraft, as it directly affects the performance of the aircraft's environmental control system.

Other choices relate to incorrect functions—such as closing the bag vent valve, entering a manual mode, or releasing pressure immediately—which do not accurately describe the operational outcome of setting the switch to the ON position.