During rapid decompression, which of the following occurs?

• A. Oxygen masks will drop down
• B. The flight crew will perform a safety briefing
• C. The engines will shut down
• D. The cabin lights switch off

Answer: (A)

When cabin pressure drops suddenly, the immediate safety response is to provide breathable air to everyone on board. The system is designed so the oxygen masks automatically deploy from the overhead panels, dropping down for passengers to use right away. This keeps people from becoming hypoxic while the crew handles the situation and guides the aircraft to a safer altitude.

The other options aren’t automatic actions tied to a rapid decompression. A safety briefing isn’t given during the emergency itself, engines don’t shut down simply because of a loss of pressurization, and cabin lighting isn’t the primary automatic response of a decompression event (emergency lighting might be involved later if power or visibility is affected, but it isn’t the immediate action described).