Which sign will illuminate during rapid decompression?

• A. Fasten Seat Belts sign
• B. No Smoking sign
• C. Overhead bin warning
• D. Engine fire warning

Answer: (A)

During rapid decompression the cabin loses pressure suddenly, and people can be thrown around or injured. The most effective and immediate safety cue is the sign that tells everyone to fasten their seat belts. Illuminating this sign prompts passengers to buckle up and stay seated, which minimizes movement injuries and helps crew maintain control as the aircraft descends to a safer altitude and cabin conditions stabilize. The other signs aren’t triggered by a pressure drop themselves: the No Smoking sign is a general rule for the flight; an overhead bin warning relates to bin security rather than decompression; and the engine fire warning indicates an engine issue, not a cabin-pressure event.