Which action will likely drain the O2 supply if not done at the end of a flight?

• A. Forgetting to turn the O2 lever to OFF at the end of a flight
• B. Leaving the O2 lever ON after landing
• C. Turning the O2 lever to OFF
• D. Opening the O2 bottle valve fully

Answer: (A)

Oxygen management hinges on stopping flow when it’s not needed. The oxygen system’s lever controls whether oxygen is being delivered to the cockpit/cabin. If you forget to switch the lever to OFF at the end of a flight, the system remains open and continues to feed oxygen, so the bottle will be drained even while the aircraft is on the ground. Turning the lever OFF at shutdown stops the flow and preserves the remaining supply for the next flight. Leaving the lever ON after landing would cause the same unnecessary drain, which is why the end-of-flight shutdown is emphasized. Opening the bottle valve fully would increase consumption even more and isn’t part of proper end-of-flight procedure.