Conventional Mechanical
•Pilot input mechanically connected to flight control hydraulic servo-actuator by cables, linkages, bellcranks
•Servo-actuator follows pilot command with high force output
•Autopilot input mechanically summed
•Manual reversion in case of loss of hydraulics or autopilot malfunction
Fly-by-Wire
•Pilot input read by computers
•Computer provides input to electrohydraulic flight control actuator
•Control laws include
•Enhanced logic to automate many functions
•Artificial damping and stability
•Flight Envelope Protection to prevent airframe from exceeding structural limits
•Multiple computers and actuators provide sufficient redundancy – no manual reversion
