What is the primary purpose of the aircraft's hydraulic system?

The primary purpose of the aircraft's hydraulic system is to operate control surfaces and other mechanical systems. Hydraulic systems use pressurized fluid to transmit power, which makes them highly effective for moving heavy components with precision, such as flaps, ailerons, and landing gear. This is essential for the aircraft's maneuverability and functionality during various phases of flight, including takeoff, landing, and in-flight adjustments.

In addition to control surfaces, hydraulic systems may also operate braking systems, cargo doors, and other vital systems. The effectiveness and reliability of hydraulic systems make them a cornerstone of modern aircraft design, allowing for smoother and more responsive handling.

The other options do not align with the primary role of hydraulic systems. For instance, while engines are powered by fuel and electrical systems, they do not rely on hydraulics for their basic operation. Similarly, electrical power is generated by the aircraft's generators, and managing fuel distribution involves other systems entirely, not hydraulics. Therefore, the focus on control surfaces and mechanical systems accurately captures the essence of the hydraulic system's primary function in aviation.