Because of the complexity and interrelationships of the flight control systems of newer model aircraft, only a brief description of a representative stabilizer control (pitch/roll. axis) follows. This system allows pitch about the aircrafts lateral axis and roll about the aircrafts longitudinal axis.

Stabilizer control, which affects both the pitch and roll axis, is provided by forward or aft and/or left or right movement of the control stick grip. Forward or aft movement provides pitch-axis control; left or right movement, roll-axis control. The control, stick grip movement is mechanically transferred to the left and right stabilizer servo cylinders through the pitch and roll command summing network, the feel assemblies, and the summing network. These servo cylinders, which are normally powered by the flight and combined hydraulic power systems, move the stabilizers. If both hydraulic systems fail, the stabilizer servo cylinders automatically receive hydraulic power from the backup system. The trim switch on the control stick grip enables trimming of the aircraft in pitch and roll.

Lateral control systems control roll about the longitudinal axis of the aircraft. In this section, several of the different system arrangements used by aircraft manufacturers are described, and general maintenance requirements for primary flight control systems are discussed.


Figure 9-8.Hydraulically powered aileron control system.