Why must gear doors be interlocked with the gear extension/retraction cycle?

• A. To ensure doors are closed before extension.
• B. To ensure doors are fully open before extension and fully closed before retraction, preventing gear damage and streamlining.
• C. To monitor hydraulic pressure.
• D. To activate ground spoilers.

Answer: (B)

The main idea is ensuring safe, coordinated movement between the gear and its doors so nothing interferes with deployment or stowage and so the aerodynamics stay clean in flight.

Gear must extend only when the doors are fully open. If the doors aren’t opened first, the gear could collide with the doors, bind, or fail to seat properly in the wheel well. The interlock prevents extension until door position is correct, guarding against damage and improper gear deployment.

Similarly, before the gear retracts, the doors must be fully closed. Closing around the gear properly ensures the doors don’t strike or jam during retraction and that the wheel well becomes aerodynamically sealed for a clean, streamlined profile, which reduces drag.

So this interlock sequence—doors open for extension, doors closed for retraction—protects the mechanism and improves aerodynamics. The other options don’t address the essential door positions required to physically move the gear or to maintain a smooth, drag-minimized profile.