Why are redundant gear actuators used on large airplanes?

• A. To simplify maintenance by using a single actuator.
• B. To ensure continued operation if one actuator or circuit fails; enhances safety.
• C. To reduce weight by removing crossfeed.
• D. To allow manual gear extension in flight.

Answer: (B)

Redundancy in flight-critical gear systems is all about staying operable even if something fails. Large airplanes rely on gear that must deploy reliably in takeoff, landing, and emergencies, so engineers use multiple actuators and often separate hydraulic circuits. If one actuator or its power path fails, the remaining actuator(s) can still extend or retract the gear, preventing a gear-up or gear-collapse scenario and keeping safe operation possible.

That’s why the main idea is about fault tolerance and safety: having more than one actuator provides a backup path for movement and reduces the chance that a single fault grounds the gear system. The idea of simplifying maintenance with a single actuator isn’t aligned with the safety goal of always having drive available. Removing crossfeed to save weight isn’t the aim of redundancy, since redundancy typically involves providing independent paths so a failure in one path doesn’t cripple the system. While some designs may include manual extension as a secondary option, redundancy’s primary purpose is to ensure continued gear operation in the presence of faults, not to enable manual extension as the main feature.