In AUTO, under what conditions do the seatbelt signs automatically illuminate?

• A. Cabin altitude above 10,000 ft, landing gear extended, or flaps greater than 0 degrees.
• B. Cabin altitude below 3,000 ft with flaps 0.
• C. During takeoff and landing.
• D. When the airplane is cruising at altitude with no passengers.

Answer: (A)

Automatic illumination of the seatbelt signs happens when the aircraft is in flight configurations that require passengers to be seated with belts fastened. In this context, the signs will turn on automatically whenever any of these conditions are present: cabin altitude exceeds 10,000 feet, landing gear is extended, or flaps are set to a position greater than zero degrees.

Why these conditions matter: above 10,000 feet the risk of turbulence is more likely, so it’s prudent to have belts fastened. When the landing gear is extended, you’re typically in the approach or landing phase, where maneuvers can be abrupt and securing passengers is important. Flaps greater than zero indicate the aircraft is not in its clean cruise configuration, usually during takeoff or approach, when slower speeds and higher responsiveness make belt use more necessary for safety.

The other statements don’t define the automatic triggers: a low cabin altitude with flaps at zero isn’t a standard automatic condition, takeoff and landing describe phases rather than the exact automatic criteria, and cruising at altitude with no passengers isn’t a valid trigger.