Standby Hydraulic System

The standby hydraulic system provides backup if system A and/or B pressure is lost. It uses an electric motor driven pump and can be activated manually or automatically.

Manual Operation (FLT CONTROL switch STBY RUD)

activates standby electric motor driven pump
shuts off related hydraulic system pressure to ailerons, elevators, rudder by closing flight control shutoff valve
opens the standby rudder shutoff valve
deactivates related flight control LOW PRESSURE light
allows standby system to power the rudder and thrust reversers
illuminates STBY RUD ON, Master Caution, FLT CONT lights

Manual Operation (ALTERNATE FLAPS master switch ARM)

activates standby electric motor driven pump
closes trailing edge flap bypass valve
arms ALTERNATE FLAPS position switch
allows standby system to power the leading edge flaps and slats and thrust reversers