The standard duration of oxygen output for passenger oxygen generators is how many minutes?

• A. 9 minutes
• B. 13 minutes
• C. 17 minutes
• D. 22 minutes

Answer: (B)

The key idea is that passenger oxygen systems are designed to provide breathable oxygen for a fixed, sufficient period after depressurization. Passenger oxygen masks use chemical oxygen generators that release oxygen for about 13 minutes, a duration chosen to cover the time needed for an emergency descent to a safe cabin altitude and to allow the situation to stabilize. This ensures there’s enough oxygen for most of the initial crisis without requiring larger or longer-lasting systems. That’s why 13 minutes is the standard duration. Shorter times wouldn’t guarantee enough breathing time during descent, while longer times aren’t the typical design for passenger masks.