Which statement about the automatic seatbelt illumination in AUTO mode is true?

• A. It illuminates when cabin altitude exceeds 10,000 ft
• B. It illuminates when landing gear extended
• C. It illuminates when cabin altitude exceeds 10,000 ft and gear extended
• D. It illuminates when cabin altitude exceeds 10,000 ft, gear extended, and flaps greater than 0

Answer: (D)

In AUTO mode, the automatic seatbelt illumination uses three inputs to decide when to light: cabin altitude, landing gear position, and flaps position. The system is designed to turn on only when all three conditions indicate a phase of flight where passengers should be secured—cabin altitude above 10,000 ft, gear extended, and flaps greater than zero. This combination signals a transition toward approach or a safer, stabilized configuration where turbulence or unexpected maneuvers could occur, so the illumination helps ensure passengers buckle up.

If any one of these conditions isn’t met, the sign stays off, avoiding unnecessary illumination during cruise or other phases. Therefore, the statement that describes the trigger as requiring all three conditions—cabin altitude over 10,000 ft, gear extended, and flaps greater than 0—is the correct one.