What should be done when the OBOGS becomes inoperative?

When the On-Board Oxygen Generating System (OBOGS) becomes inoperative, the immediate response is to pull the green ring. This action initiates the deployment of the emergency oxygen system, allowing the pilot to secure a supplemental oxygen supply. In situations where OBOGS fails, having reliable access to oxygen is crucial to ensuring that the pilot can continue to function effectively at altitude where the oxygen levels are insufficient for normal breathing.

While checking oxygen levels or turning off the Power Control Lever (PCL) may seem like reasonable actions, they do not directly address the immediate need for oxygen in an emergency situation. Deploying the emergency oxygen system is the priority to ensure the safety of the pilot. Pulling the ejection handle is a drastic measure that is typically reserved for situations where there is no other option available, making it an inappropriate response for a simple OBOGS failure. Thus, pulling the green ring to access the emergency oxygen is the correct and most effective course of action.