At which cabin altitude will O2 masks drop down automatically?

• A. 12,000 ft
• B. 14,000 ft
• C. 16,000 ft
• D. 18,000 ft

Answer: (B)

Oxygen masks drop automatically when the cabin altitude climbs to about 14,000 feet. This threshold is used because, at that level, the air inside a pressurized cabin becomes low enough in oxygen that people can start to hypoxize unless they receive supplemental oxygen. Triggering at 14,000 feet provides timely protection for everyone on board while avoiding unnecessary deployment at lower, safer altitudes. The other numbers are not the standard trigger points for passenger oxygen mask deployment, so 14,000 feet is the correct reference.