CL-600 Autoflight Control System

The automatic flight control system provides integrated three axis control, guidance and stabilization. It employs dual channel computation driving dual servos or actuators in all three axes (roll, pitch and yaw).


The AFCS consist of three systems:

Stability Augmentation provides yaw damper, turn coordination and Mach trim.

Flight Director provides command information to the pilot and/or the autopilot to maintain selected pitch and roll parameters. It is the “brain” of the autopilot/flight director.

Autopilot provides “muscle” to fly the aircraft by converting flight director/pilot command into control surface movement in the pitch and roll axes.

The stability augmentation is normally engaged throughout flight and stands apart from the rest of the system. It provides control in the yaw axis (rudder) and an output to the horizontal stabilizer.The flight director comprises two independent systems one each for the pilot and co-pilot providing commands in the pitch and roll axes. It will command pilot action by positioning a cue bar in his ADI (Attitude Director Indicator), or autopilot action as selected. The autopilot may be engaged with or without flight directors and responds to commands from the pilot, or either (but not both) flight director. It provides control in roll (ailerons), pitch (elevator) and automatic pitch trim (horizontal stabilizer) when engaged.The vertical navigation computer/controller provides commands to the no.1 flight director computer to maintain a selected vertical (pitch) flight path.

Engagement and basic control of the system is accomplished from the autopilot controller. This panel, located on the center pedestal, contains the AP Engage, YD Engage, Couple, Soft Ride pushbuttons and the Pitch Wheel and Turn Knob. The instrument remote controller located on the center pedestal is the means by which pilots select heading and course on their HSIs (Horizontal Situation Indicator).The vertical navigation computer/controller is located on the center instrument panel and provides three facilities:

Altitude Alerting
Altitude Preselect
Vertical Navigation

Modes are selected on the flight director mode selectors (one for each system) which are located on the glareshield. Both flight directors may have different modes engaged, but only one may be coupled to the autopilot at any one time.

“Autoflight Control System.” Canadair Challenger 601 Training Guide. August 1984: Chapter 10