Figure 9-2 shows a mechanically controlled, hydraulically assisted system. Because these systems reduce pilot fatigue and improve system performance, they are now commonly used. Such systems include automatic pilot, automatic landing systems, and stability augmentation systems. Navy specifications require two separate hydraulic systems for operating the primary flight control surfaces. Current specifications call for an independent hydraulic power source for emergency operation of the primary flight control surfaces.
Some manufacturers provide an emergency system powered by a motor-driven hydraulic pump.
Many aircraft use a conventional elevator system for this purpose. Aircraft that operate in the higher speed ranges usually have a movable horizontal stabilizer. Integrated Publishing's Official Web Page Click here for a current index of everything on this web site. All Rights Reserved.