How is the landing gear retraction and extension powered under normal conditions, and what is used for emergency extension?

• A. Normal: Electric; Emergency: Gravity
• B. Normal: Hydraulic; Emergency: Electric
• C. Normal: Pneumatic; Emergency: Hydraulic
• D. Normal: Mechanical springs; Emergency: Gravity

Answer: (A)

Landing gear retraction and extension on the PC-12 NGX is driven by an electric-powered hydraulic system in normal operation. An electric motor powers a hydraulic pump, and the hydraulic actuators move the gear through its retract and extend cycles. If electrical power (or hydraulic pressure) is lost, the design provides for emergency extension using gravity: once the release mechanism is used, the gear can descend and lock down under gravity, allowing a safe landing even without normal power. This is why electric power is listed for normal operation and gravity is used for emergency extension.