A system of fall back flight control configured for use in electric aircraft includes an input control configured to receive a pilot input and generate a control datum. System includes a flight controller communicatively coupled to the input control and configured to receive the control datum and generate an output datum. The system includes the actuator having a primary mode in which the actuator is configured to move the at least a portion of the electric aircraft as a function of the output datum and a fall back mode in which the actuator is configured to move the at least a portion of the aircraft as a function of the control datum. The actuator configured to receive the control datum, receive the output datum, detect a loss of communication with the flight controller, and select the fall back mode as a function of the detection.

Aircraft, fly-by-wire systems, and controllers are provided. An aircraft includes a trim control system and a fly-by-wire system. The trim control system is configured for controlling surfaces of the aircraft. The fly-by-wire system is communicatively coupled with the trim control system and includes an input device and a controller. The input device is configured to receive a re-trim input from a user. The controller is communicatively coupled with the input device and is configured to control the trim control system, to obtain the re-trim input from the user, and to set a pitch trim of the aircraft based on a stable flight condition at a present airspeed of the aircraft in response to the re-trim input from the input device.

A method for providing adaptive control to a fly-by-wire aircraft includes measuring via at least one first sensor a characteristic of at least one component of the aircraft and measuring via at least one second sensor a state of the aircraft. Using the characteristic of at least one component and the state of the aircraft, a determination of at least one of an actual damage and remaining life of the at least one component is made. The operational envelope of the aircraft is adapted based on the at least one of actual damage and remaining life of the at least one component. Adapting the operational envelope includes adjusting an outer boundary thereof to prohibit operation exceeding a safe operation threshold and generating an intermediate boundary of the operational envelope. Operation of the aircraft within the intermediate boundaries minimizes further damage accrual of the at least one component.

An actuator system for controlling a movable surface has a main shaft connected between a power drive unit and the movable surface to transmit a command from the power drive unit to move the movable surface. If a failure in the main shaft is detected a failure control device connects a secondary shaft from the movable surface to the power drive unit e.g. by releasing a solenoid which releases gears so as to permit differential rotations between an outer ring and a sun gear of a planetary gear system, within prescribed limits. When these limits are exceeded, the solenoid brake is de-energised braking the planetary gear outer ring and tying the gears through an epicycle ratio corresponding to the ratio of gears connecting the main and secondary shafts. The gear system acts as a low mass asymmetry brake that allows post-failure operation of the surface control.

Methods and apparatus for enhancing aircraft flight control surface effectiveness via forced oscillation are described. An example control system of an aircraft includes a flight control surface, an actuator, and one or more processors. The actuator is configured to move the flight control surface. The one or more processors are configured to determine a current position of the flight control surface. The one or more processors are further configured to determine whether the current position exceeds a position threshold. The one or more processors are further configured to generate a forced oscillation signal in response to determining that the current position exceeds the position threshold. The one or more processors are further configured to command the actuator to move the flight control surface based on the forced oscillation signal.

A Stability and Control Augmentation System (“SCAS”) module comprising one or more SCAS actuators, the or each SCAS actuator comprising a mechanical component that translates rotational motion to linear motion along a first axis of said SCAS; one or more electric motors for driving linear movement of the mechanical component in response to a command signal; and one or more angular transducers to detect the position of the SCAS actuator along the first axis.

A control circuitry includes a first filter configured to filter a gravity compensated longitudinal acceleration of an aircraft to generate a filtered gravity compensated longitudinal acceleration. The propulsor trim control circuitry also includes a second filter configured to generate a filtered speed of the aircraft based on a speed of the aircraft. The propulsor trim control circuitry includes intermediary circuitry configured to generate a filtered longitudinal control effector error based on the filtered gravity compensated longitudinal acceleration and the speed. The propulsor trim control circuitry also includes a third filter configured to generate a filtered longitudinal thrust effector command value based on a longitudinal thrust effector command value. The propulsor trim control circuitry further includes output circuitry configured to generate a predicted longitudinal thrust effector trim value for a target horizontal state based on the filtered longitudinal control effector error and the filtered longitudinal thrust effector command value.

Methods and apparatus for enhancing aircraft flight control surface effectiveness via forced oscillation are described. An example control system of an aircraft includes a flight control surface, an actuator, and one or more processors. The actuator is configured to move the flight control surface. The one or more processors are configured to determine a current position of the flight control surface. The one or more processors are further configured to determine whether the current position exceeds a position threshold. The one or more processors are further configured to generate a forced oscillation signal in response to determining that the current position exceeds the position threshold. The one or more processors are further configured to command the actuator to move the flight control surface based on the forced oscillation signal.

A method of controlling an elevator of an aircraft includes selecting a factor for increasing or decreasing a predetermined horizontal tail load alleviation (HTLA) authority limit for an elevator based on at least one aircraft parameter. The HTLA authority limit decreases with an increase in Mach number and/or airspeed. The method also includes computing an elevator position limit as a product of the HTLA authority limit and the factor, and moving the elevator to a commanded elevator position that is no greater than the elevator position limit.

An actuation system comprises a plurality of actuators, a common power drive unit for driving the actuators and a transmission line transmitting drive from the common drive unit to the plurality of actuators. A clutch is arranged in the transmission line between the power drive unit and the plurality of actuators for selectively disconnecting the power drive unit from the plurality of actuators. At least one sensor is provided for sensing an abnormal load condition in the actuation system. The at least one sensor is operatively coupled to a clutch control which is configured such that when the at least one sensor senses an abnormal load condition, the clutch control is operative to disengage the clutch so as to disconnect the power drive unit from the plurality of actuators. A brake is operative to brake the actuators upon disengagement of the clutch.