Apparatus and associated methods relate to differentiating ice accretion caused by different supercooled water droplets on an airfoil of an aircraft. A sensor having a sensing surface region is mounted at a mounting location of the airfoil such that the sensing surface region is flush with a surrounding adjacent surface of the airfoil. Water particles of sizes less than or equal to a predetermined threshold do not impinge the sensor surface region at the mounting location when the aircraft is in flight. A sensor driver provides an excitation signal to the sensor. A signal detector detects a sensor signal responsive to the provided excitation signal. The sensor signal is indicative of water particles exceeding the predetermined threshold impinging the sensing surface region. In some embodiments, the sensing surface region is mechanically coupled to a resonant cavity. In other embodiments, the sensor is a surface resistance sensor configured to sense surface resistance.

A system and method to modify a qualified actuator command with an unqualified actuator command modifier. The method includes creating a modified actuator command as the difference between the qualified actuator command and the unqualified actuator command and thereafter limiting the modified actuator command with an authority limiter. The system includes a qualified computer having an unqualified control law interfaced with an unqualified computer having a qualified control law.

A sub-system 200 for an aircraft hydraulic system 20 that includes a first inlet 202 for receiving fluid from a supply 22 of hydraulic fluid, a system valve 210 for controlling fluid flow from the sub-system 200 to a hydraulically-operable system 24 of the aircraft hydraulic system 20, a check valve 220 for permitting fluid flow from the sub-system 200 and preventing or hindering fluid flow into the sub-system 200, a second inlet 240 for receiving fluid from a second supply 28 of hydraulic fluid, and a selector 230. The selector 230 configured to place the system valve 210 in fluid communication with the first inlet 202 when the selector 230 is in a first state, and to place the system valve 210 in fluid communication with the check valve 220 and the second inlet 240 when the selector 230 is in a second state different from the first state.

An aerodynamic structure incorporated in an aircraft control surface (10) provides a spar (16) extending along at least a portion of the control surface in a direction and the spar includes a plurality of bends along the direction of extension along the control surface to provide space to accommodate actuator fittings or other structural or operational requirements.

A method of controlling an aircraft electrical taxiing system, the method comprising the steps of: defining a target value (Ld_nmax) for an electrical parameter; generating a nominal force command (Cmd_nom) for the electrical taxiing system; in parallel with generating the nominal force command (Cmd_nom), using a processing system (2) to produce a maximum command force (Force_max) for the electrical taxiing system so that a real value of the electrical parameter reaches the target value (Ld_nmax), the processing system (2) comprising a regulator loop (4); and generating an optimized force command (Cmd_opt) for the electrical taxiing system equal to the smaller of the nominal force command and the maximum command force.

A method of controlling an aircraft electrical taxiing system, the method comprising the steps of: defining a target value (Ld_nmax) for an electrical parameter; generating a nominal force command (Cmd_nom) for the electrical taxiing system; in parallel with generating the nominal force command (Cmd_nom), using a processing system (2) to produce a maximum command force (Force_max) for the electrical taxiing system so that a real value of the electrical parameter reaches the target value (Ld_nmax), the processing system (2) comprising a regulator loop (4); and generating an optimized force command (Cmd_opt) for the electrical taxiing system equal to the smaller of the nominal force command and the maximum command force.

A proportional braking system is provided for use with a movable surface which is movable relative to a housing. The proportional braking system includes a variable displacement brake which is configured for displacement toward or away from braking engagement with the movable surface in proportion to an input command and a brake driver which is receptive of data reflective of movements of the movable surface relative to the housing and which issues the input command to the variable displacement brake in accordance with the data.

A method for position hold override control of an aircraft includes determining, by a processor, that a position hold mode is enabled to hold the aircraft at a substantially fixed position with respect to a target. The processor receives a control input indicative of a commanded change in acceleration of the aircraft as an override of the position hold mode. The processor determines an acceleration command based on the commanded change in acceleration. The acceleration command is adjusted as an adjusted acceleration command responsive to a non-linear scheduled translational rate command based on feedback of a commanded velocity of the aircraft. An update to the commanded velocity of the aircraft is generated based on the adjusted acceleration command.

A system for driving and guiding a trailing edge control surface on a trailing edge region of an aircraft wing comprises a first guide device coupled with the control surface to guide the control surface along a predetermined trajectory relative to the trailing edge region between a retracted position and an extended position, a first drive device couplable with the wing and the control surface to move the control surface along the trajectory, and a second drive device coupled with the control surface and couplable with one of the wing and the first guide device to influence the incidence angle of the control surface, wherein the first drive device and the second drive device are separate from each other and are operable independently, such that the incidence angle of the control surface is influencable at least in the retracted position of the control surface.

The present disclosure provides systems and methods for communicating between control systems via hydraulic fluid. In one example embodiment, a computer-implemented method includes operating a first pressure regulating device associated with a first control system to regulate a fluid pressure of hydraulic fluid being supplied through a hydraulic line, the first pressure regulating device being in fluid communication with a hydraulically actuated component via the hydraulic line. The method includes controlling the operation of the first pressure regulating device to generate a fluid-pressure based signal within the hydraulic line, the signal providing an indication of an operational status of at least one of the first control system or the hydraulically actuated component. The method includes detecting pressure changes within the hydraulic line associated with the signal to allow a second control system to monitor the operational status of the first control system and/or the hydraulically actuated component.