How many oxygen masks are there in each PSU?

• A. At least one more than the number of seats
• B. Exactly as many as seats
• C. At least two fewer than seats
• D. One per row of seats

Answer: (A)

Oxygen masks in each PSU are counted to ensure every passenger in the area has access to a mask, with a safety cushion built in. The design includes one mask for every seat in that PSU’s seating group plus an extra mask kept as a spare. This redundancy accounts for potential mask damage or misplacement and guarantees there’s always a mask available for each passenger in that zone. For example, if a row has six seats, the PSU would contain six passenger masks plus one additional spare mask, totaling seven. That built-in extra means there are at least one more mask than there are seats, which is why the correct answer says there are at least one more than the number of seats.