When is oxygen supplied from a continuous flow oxygen system?

In a continuous flow oxygen system, oxygen is provided to the user during inhalation, which typically occurs after the reservoir bag has been depleted. The design of this system ensures that a steady flow of oxygen is available when the user inhales, permitting adequate oxygen intake, especially in scenarios where supplemental oxygen is necessary, such as at altitude.

At high altitudes or in situations of reduced cabin pressure, it's critical that passengers and crew receive supplemental oxygen to counteract the effects of decreased atmospheric oxygen levels. When a continuous flow system operates, it does not provide a constant supply; rather, it delivers oxygen precisely when needed—during the inhalation phase—ensuring that the user receives the oxygen they require without overwhelming them or wasting the resource when they exhale.