In an aircraft, what is the primary use of hydraulic systems?

The primary use of hydraulic systems in an aircraft is to extend and retract landing gear. Hydraulic systems are essential for providing the necessary force to operate various mechanical components within the aircraft, particularly those that involve heavy loads or require precise movement.

When it comes to landing gear, the hydraulic system generates the pressure needed to lift and lower the gear during takeoff and landing. This is crucial as it not only ensures the gear is securely in place when the aircraft is on the ground but also allows for smooth and rapid deployment when needed.

Overall, while hydraulic systems can assist with other functions, such as controlling flaps or aiding in engine operations, their most critical and recognized role in aviation is facilitating the operation of landing gear, which is a safety feature vital for successful flight operations.