Landing gear doors function to:

• A. Open to allow radar
• B. Close over the gear and reduce drag and fuel consumption
• C. Serve as the door for maintenance
• D. Lock the gear in the up position

Answer: (B)

Landing gear doors seal the wheel well when the gear is retracted, creating a smooth, uninterrupted surface for the airflow. This aerodynamic seal reduces parasitic drag, which lowers drag on the airplane and helps improve fuel efficiency and speed. The doors open to let the wheels deploy during extension and then close again once the gear is up, preserving that streamlined shape in flight. They also protect the gear bay from debris and weather. They aren’t used to allow radar access, nor are they the mechanism that locks the gear in place—the uplock and gear actuators handle that, while the doors focus on aero sealing and protection.