Which hydraulic system powers the landing gear?

• A. System 1
• B. System 3
• C. System 2
• D. All three

Answer: (B)

Hydraulic circuits are arranged with separate paths so critical functions can operate independently. The landing gear uses a dedicated hydraulic circuit, System 3, to power its extension and retraction actuators. This design provides a reliable, isolated source of pressure for gear movement, so deployment can occur even if other systems are unavailable. Systems 1 and 2 handle other functions like flight controls, flaps, or brakes, and aren’t the source for gear operation in this setup. Keeping the landing gear on System 3 ensures it has a dedicated, reliable power path, which is why that choice is correct.