A backup system is provided that has a local electric motor and pump for
some or all of the hydraulic actuators on an aircraft. A local backup
hydraulic actuator has two power sources, hydraulic as primary and
electrical as backup. During normal operation, the hydraulic actuator
receives pressurized fluid from a hydraulic system and the fluid flow to
the chambers is controlled by a servo valve. If the hydraulic system
fails, the electronic controller detects the failure by observing the
signal indicative of the pressure from the pressure sensor, and the
controller powers the local hydraulic pump to provide high pressure
hydraulic fluid to the hydraulic actuator via the servo valve.