This subcourse is designed to provide instruction on the concept and operation of the basic components of the hydraulic system. It also describes the various components of a typical hydraulic system, their construction and functions, and their relationship to each other.

When the term hydraulics is applied to aircraft, it means a method of transmitting power from one location to another through the use of a confined fluid. The functions performed by hydraulic systems in aircraft include assisting in flight control, extending and retracting landing gear, positioning flaps, operating hoists, raising and lowering cargo doors, and starting engines.

The hydraulic systems used in Army aircraft are dependable and relatively trouble-free. The maintenance requirements are small in comparison to the work the system performs.