How do gear doors ensure safe movement during extension and retraction?

• A. Door interlocks and sequencing valves ensure doors and gear move in the correct order to prevent interference.
• B. There is no requirement for doors to coordinate with gear motion.
• C. Doors are designed to accelerate independently of gear motion.
• D. Doors are controlled solely by hydraulic pressure with no interlocks.

Answer: (A)

The movement of gear doors is tightly coordinated with the gear itself to prevent any interference or damage. Interlocks and sequencing valves make sure the doors operate in the correct order relative to the gear’s position. This means doors won’t start to open while the gear is still reeling in or out, and they won’t close until the gear is fully stowed. Position sensors feed the system so that door motion is locked in place if the gear isn’t in the proper position, and doors are commanded to open or close only when it’s safe. This coordinated control keeps the doors from colliding with the landing gear or wheels, ensures proper sealing when retracted, and prevents hydraulic or structural damage.

Without interlocks, doors could move at the wrong time, risking interference. Doors that accelerate independently of the gear or are driven solely by hydraulic pressure without sequencing could misalign with gear movement and cause damage or improper closure.