Which statement about the sterile flight deck light is true?

• A. It signals that contact with the flight deck is permitted for any reason.
• B. It is illuminated after the boarding door closes and before surface movement, and is turned off above 10,000 feet.
• C. It remains on during takeoff and landing.
• D. It is turned on only after the aircraft parks.

Answer: (B)

The sterile flight deck light marks the period when only essential actions and communications are allowed in the flight deck. It comes on after the boarding door is closed and before the aircraft starts moving on the ground, signaling cabin crew to keep nonessential conversations and activities to a minimum and to avoid approaching the flight deck unless necessary. The light stays on through taxi, takeoff, and the approach/landing phases, ensuring pilots have a quiet, uninterrupted environment when attention is most critical. It is turned off once the aircraft climbs above 10,000 feet, at which point the sterile cockpit restrictions ease and normal cabin activity can resume. This timing matches the standard practice that sterile conditions apply during the critical phases from door closure up to reaching 10,000 feet.