What provides the flight crew with oxygen in an A320?

In the A320, the flight crew is provided with oxygen through a gaseous bottle. This system is designed to supply oxygen to the crew members in case of an emergency, such as cabin depressurization. The gaseous oxygen system utilizes compressed oxygen stored in a tank that can be readily accessed and delivered to the crew through masks.

This method ensures that, in an emergency, the crew has immediate access to oxygen, allowing them to maintain consciousness and manage the situation effectively. The gaseous bottle system is beneficial because it is lightweight, reliable, and can be refilled relatively easily compared to other systems.

Options like the nitrogen generator, liquid oxygen system, and compressed air cylinder serve different purposes and are not designed to provide immediate oxygen to the flight crew. The nitrogen generator is primarily used for inerting fuel tanks and controlling cabin pressure, while a liquid oxygen system, though used in some aircraft, is not standard in the A320. The compressed air cylinder, generally used for pneumatic systems, would not be suitable for providing breathable oxygen to crew members.