At approximately 14,000 Feet, which event would you expect to occur automatically?

• A. Passenger O2 masks deploy
• B. Outflow Valve closes completely
• C. O2 bottle pressure increases
• D. Oxygen disk blows out

Answer: (A)

Passenger oxygen masks deploy automatically when cabin altitude reaches approximately 14,000 feet. This threshold is set so that as the cabin pressure drops with altitude, occupants receive oxygen without delay to prevent hypoxia. The system uses a cabin altitude sensor to trigger the mask drop, and oxygen begins to flow as soon as the masks are deployed. The outflow valve is part of maintaining cabin pressure and does not close completely as a response to reaching this altitude, and it isn’t responsible for mask deployment. Oxygen bottle pressure does not rise automatically at this altitude; the bottles remain pressurized and supply oxygen only once the system is activated. The notion of an “oxygen disk blowing out” isn’t part of the normal automatic deployment sequence.