| Rudder The rudder provides yaw control about the airplane's vertical axis. The A
and B FLT CONTROL Switches control hydraulic shutoff valves for the
rudder and the standby rudder.
Each set of rudder pedals is mechanically connected by cables to the input levers of the main and standby rudder PCUs. The Main Rudder PCU is powered by Hydraulic System A and B. Airplanes without SEL 11 At speeds above approximately 135 kts, Hydraulic System A pressure to the rudder PCU is limited by approximately 50%. This function limits full rudder authority in flight affer takeoff and before landing. Airplanes with SEL 11 At speeds above approximately 135 kts, both Hydraulic System A and B pressure are each reduced within the main PCU by approximately 25% each. This function limits full rudder authority in flight after takeoff and before landing. The Main Rudder PCU contains a Force Fight Monitor (FFM) that detects opposing pressure (force fight) between A and B actuators. This may occur if either system A or B input is jammed or disconnected. The FFM output is used to automatically turn on the Standby Hydraulic pump, open the Standby Rudder Shutoff Valve to pressurize the Standby Rudder PCU, and illuminate the STBY RUD ON, Master Caution, and Flight Control (FLT CONT) Lights. Standby Rudder The Standby Rudder PCU is powered by the Standby Hydraulic System. The Standby Hydraulic System is provided as a backup if System A and / or B pressure is lost. With the Standby PCU powered the pilot retains adequate rudder control capability. It can be operated manually through the FLT CONTROL Switches or automatically. |