At what altitude do passenger O2 masks automatically deploy?

• A. 10,000 Feet
• B. 12,000 Feet
• C. 14,000 Feet
• D. 16,000 Feet

Answer: (C)

When cabin pressure drops, the air inside becomes thinner and the amount of oxygen available to the body falls. To protect passengers from hypoxia, oxygen masks are designed to automatically drop at a specific cabin altitude, triggering oxygen flow without any action from you. That automatic deployment happens at 14,000 feet, a point chosen because above this altitude the body won’t get enough oxygen quickly enough to stay safe during a depressurization.

Think of it as a safety threshold that balances being proactive with practicality. If masks deployed too early, during normal high-altitude cruise when the cabin is still pressurized to a safe level, it would be unnecessary and disruptive. If they deployed too late, passengers could begin to suffer hypoxia before help could be provided. The 14,000-foot mark ensures oxygen is available promptly in a loss-of-pressurization event, giving time for the aircraft to descend to a safe altitude or for the crew to manage the situation.