How long shall the oxygen system stabilize before use?

• A. 15 minutes
• B. 45 minutes
• C. At least 30 minutes
• D. 60 minutes

Answer: (C)

When an oxygen system has been serviced or installed, it needs time to come to a stable operating state before it’s used. This stabilization period lets the system reach pressure and temperature equilibrium, ensures the regulators and valves seat properly, and allows any residual moisture or contaminants in the lines to be purged. Giving it at least 30 minutes ensures the oxygen output will be steady and within safe limits when the crew opens the flow valve at altitude. Shorter times may not purge the system or allow the pressure to regulate reliably, while longer times aren’t typically required for normal operation.