Hydraulic System Failure
No emergency system is provided for the hydraulically operated aerodynamic flight control system, speed brakes, and wing flaps. However, this airplane has an SAS emergency hydraulic system which automatically provides hydraulic power to the SAS pitch and roll servos in the event of a No. 2 hydraulic system failure.
If failure of one flight control hydraulic system occurs, the other system assumes the entire load of aerodynamic flight control system operation. However, under such a condition, available control surface hinge moments will be one half their design value, because of reduction of hydraulic flow. Refer to "Aerodynamic Flight Control System" for more informations.
The artificial-feel system failure can be indicated by a lightening of stick forces (resulting in overcontrol), lack of trim response, and poor stick-centering characteristics. If failure of flight control artificial feel is encountered, proceed as follows:
If the trim system fails in either extreme-travel position, the maximum force required by the pilot to move the control surface to the opposite extreme is not beyond physical capabilities. If the pitch trim knob [4, fig. 5-5] fails, the trim system can be controlled by the alternate trim switch on the center stick [8, fig. 4-1]. The trim control switch [1, fig. 5-4] must be moved to ALTERNATE before the alternate trim switch is operable.