Where can the drop-down O2 masks be found in the cabin and how many of them in each location are there?

• A. 4 masks in the PSU per seat row; 2 masks in each toilet; 2 masks above each main door
• B. 2 masks in the PSU per seat row; 4 masks in each toilet; 1 mask above each main door
• C. 3 masks in the PSU per seat row; 2 masks in each toilet; 3 masks above each main door
• D. 4 masks in the PSU per seat row; 3 masks in each toilet; 4 masks above each main door

Answer: (A)

Oxygen masks are arranged to be quickly reachable for everyone on board during a cabin depressurization, with distribution planned to cover passengers by area. In this layout, the masks are stored in the passenger service units (PSUs) above the seats, and the counts are chosen to match how many passengers sit in each section.

The drop-down masks in the PSUs above each seat row provide four masks per row—two masks on each side of the aisle—so the two seats on either side of a row can access masks promptly. Having two masks in each toilet ensures there’s a mask available in the lavatories if needed. Placing two masks above each main door makes sure crew near the exits have immediate access to oxygen as soon as deployment begins and supports quick, centralized access near the doors. This combination of locations and counts aligns with the required coverage across the cabin in the scenario described.