Abstract: A system for backdriving the flight deck controllers of a fly-by-wire aircraft that is under autopilot control to provide a pilot with tactile and visual feedback of autopilot activity. The system, distributed between the aircraft primary flight computers and the autopilot flight computer, uses actuators mechanically coupled to each flight deck controller to position the flight deck controller to mimic manual operation of the flight control surfaces. Additionally, the system allows smooth disengagement of the autopilot and transfer of the aircraft to pilot control when the pilot takes control of any flight deck controller by moving it from a backdrive system-commanded position by a predetermined displacement for a predetermined time.

Abstract: An underspeed protection system for an aircraft under autopilot control selects a target speed based upon the greater of a minimum maneuver speed and a stick shaker speed. The system then compares a monitored speed to the target speed to produce an error signal. The system also monitors vertical speed to determine if tie aircraft begins to descend. If the error signal due to the underspeed condition causes the aircraft to descend, the system provides a hold zero vertical speed signal in place of the error signal such that the aircraft seeks to maintain its altitude. The hold zero vertical speed signal overrides the underspeed error signal such that the aircraft does not pitch forward to seek an increased speed.

Abstract: An aircraft overspeed protection system produces proportional and integral commands for input to an autopilot controlling the aircraft. The proportional and integral commands are produced by comparing actual monitored speed of the aircraft with a target speed from a target speed selector. The target speed selector selects as the target speed a trigger speed above a nominal maximum operating airspeed of the aircraft until the trigger speed is reached by the aircraft. When the trigger speed is reached by the aircraft, the overspeed control goes into Overspeed Protect Command active mode and the target speed selector selects a new target speed below the nominal maximum operating speed of the aircraft. The overspeed protection system remains in Overspeed Protect Command active mode until the pilot takes a positive action by selecting a new autopilot mode or by disengaging the autopilot.

Abstract: In an aircraft under autopilot control, a stall protection system overrides established autopilot parameters in response to a monitored angle of attack for the aircraft exceeding a trigger angle of attack. The trigger angle of attack is established with reference to a stick shaker angle of attack for the aircraft. When the aircraft exceeds the trigger angle of attack, the stall protection system produces an error signal causing the autopilot to seek an angle of attack 1 degree below the stick shaker angle of attack. Initially, the stall protection system provides a boost command to the error signal to accelerate the response of the aircraft to the error signal. The boost command is produced by a driving signal generator that selects one of four driving signals in response to monitored flap angle and impact pressure.

Abstract: A system for backdriving the flight deck controllers of a fly-by-wire aircraft that is under autopilot control to provide a pilot with tactile and visual feedback of autopilot activity. The system, distributed between the aircraft primary flight computers and the autopilot flight computer, uses actuators mechanically coupled to each flight deck controller to position the flight deck controller to mimic manual operation of the flight control surfaces. Additionally, the system allows smooth disengagement of the autopilot and transfer of the aircraft to pilot control when the pilot takes control of any flight deck controller by moving it from a backdrive system-commanded position by a predetermined displacement for a predetermined time.

Abstract: An underspeed protection system for an aircraft under autopilot control selects a target speed based upon the greater of a minimum maneuver speed and a stick shaker speed. The system then compares a monitored speed to the target speed to produce an error signal. The system also monitors vertical speed to determine if the aircraft begins to descend. If the error signal due to the underspeed condition causes the aircraft to descend, the system provides a hold zero vertical speed signal in place of the error signal such that the aircraft seeks to maintain its altitude. The hold zero vertical speed signal overrides the underspeed error signal such that the aircraft does not pitch forward to seek an increased speed.