Abstract: A ball screw comprising a screw shaft, a ball nut, and alpha and beta load circuits. The alpha and beta load circuits each include first and second parts. The screw shaft is longitudinally extending with a longitudinal central axis (A) and at least part of the longitudinally extending surface of the screw shaft comprises an external thread, and at least one of the first parts of the alpha and beta load circuits comprise a part of the external thread. The ball nut comprises a body, a bore, the second parts of the alpha and beta load circuits, and an alpha and a beta lubricant channel. The bore is defined by the body, is longitudinally extending with a longitudinal central axis (A), has a first and second end, and has at least one longitudinally extending surface extending between the first and second ends.

Abstract: A blade pitch control and protection system for a propeller includes: an actuator where displacement of said actuator corresponds to a change in blade pitch of said propeller; an electronic unit, a position control sensor configured to interact with said actuator. The position control sensor detects actuator position and thereby said blade pitch of said propeller, and to send a control feedback signal to said electronic unit via a first channel, based on said blade pitch, and a protection sensor configured to interact with said actuator, configured to detect actuator position and thereby said blade pitch of said propeller, and to send a protection feedback signal to said electronic unit via a second channel, based on said blade pitch. The electronic unit is configured to, based on said control feedback signal, control movement of said actuator to alter said blade pitch through a control command.

Abstract: A multi-layer braided article and a method of making the multi-layer braided article. The multi-layer braided article includes a braid extending along a first axis, wherein the braid is folded over itself to form a first layer and a second layer; and a wrapper laid over the first layer of the braid and extending circumferentially around the first axis, wherein the wrapper defines an edge of the first layer about which the braid is folded. The multi-layer braided article may form part of a blade for an aircraft. A sleeve may be provided around a conical portion of the article to connect the article to something else, such as a propeller hub, where the multi-layer braided article is formed as part of a blade. The sleeve may provide a primary or secondary load path.

Abstract: A pedal cartridge for an aircraft. The pedal cartridge is connectable to a pedal mechanism and includes: a pedal. The pedal includes a pedal axle receiving portion configured to receive a pedal axle of the pedal mechanism such that the pedal is rotatably connectable to the pedal axle. The mechanism also includes a first rotation sensor component, the first rotation sensor component configured to interact with a second rotation sensor component of the pedal mechanism to permit rotation of the pedal about the pedal axle to be detected.

Abstract: An apparatus for adjusting aircraft inceptor trim includes an inceptor centring device mechanically coupled to a control shaft that rotates in response to inceptor inputs. The inceptor centring device includes an inceptor centring spring preloaded with a preload force to provide a first biasing force to bias the control shaft to an inceptor neutral position. The apparatus has a trim mechanism, mechanically coupled to the inceptor centring device, and includes a trim locking device having a locked state and an unlocked state. A resistance force of the trim mechanism with the trim locking device in the unlocked state is less than the preload force, such that when the trim mechanism is in the unlocked state, actuation of the inceptor adjusts the position of the inceptor centring device to alter the degree of trim.

Abstract: An assembly for maintaining the pitch angle of a flight control surface for an aircraft. The assembly includes a shaft comprising a screw thread and defining a shaft axis, and a nut. The nut includes a housing, a barrel located in the housing and comprising a screw thread for engaging with the screw thread of the shaft, and at least one locking element located in the housing. The housing comprises a radially inner cam surface adjacent to the locking element. The barrel is configured to rotate relative to the housing when the screw thread of the barrel is engaged and rotating with the screw thread of the shaft so as to move the locking element along the cam surface from a disengaged position in which the locking element is spaced from the screw thread of the shaft, to an engaged position.

Abstract: A method of performing health monitoring for an aircraft having a variable pitch propeller system. The method includes: receiving aircraft flight information; performing a virtual pitch calculation to determine a virtual propeller pitch or virtual blade angle from the aircraft flight information; receiving a measured propeller pitch or blade angle from at least one physical sensor associated with the propeller; and using the virtual propeller pitch or virtual blade angle and the measured propeller pitch or blade angle to perform a health monitoring process to determine a health condition of at least one component of the aircraft, wherein the at least one component is distinct from the blades.

Abstract: A screw actuator includes a primary ball nut, a secondary nut, and a ball screw. The primary ball nut and secondary nut are both in threaded engagement with the ball screw, in which the inner functional plays of the screw actuator are configured such that in normal operation the threads of the secondary nut are in contact with the ball screw threads.

Abstract: A method of operating a variable pitch propeller system for an aircraft. The method includes: receiving aircraft flight information; performing a virtual pitch calculation to determine a virtual propeller pitch or virtual blade angle from the aircraft flight information; and performing a pitch protection process in response to low virtual propeller pitch or virtual blade angle being determined.

Abstract: A motor system includes a brushless motor with a stator, a rotor having a first number of rotor poles, and a motor shaft connected to the rotor. The motor system also includes control electronics configured to control a brushless motor that has a second, number of rotor poles, different from the first number of rotor poles. The second number of rotor poles is an integer multiple, N, of the first number of rotor poles. A position sensor is communicatively connected to the control electronics. A first gear is mounted on the motor shaft and connected for rotation with the motor shaft, the first gear having a first number of teeth. A second gear is engaged with the first gear, the second gear having a second number of gear teeth. The position sensor is configured to detect an angular position of the second gear and provide it to the control electronics.

Abstract: A method of operating a propeller system for an aircraft. The method includes: receiving propeller speed information, the propeller speed information indicating propeller speed; receiving a target propeller speed; performing a propeller speed threshold adjustment process, the propeller speed threshold adjustment process comprising adjusting a propeller speed threshold as a function of the target propeller speed; comparing the propeller speed to the propeller speed threshold; and in response to propeller speed exceeding the propeller speed threshold, performing an overspeed protection process.

Abstract: A pneumatic release system has an inlet arranged to be connected, in use, to a supply of pressurised fluid, and an outlet arranged, to be connected, in use, to an end device. The system defines therethrough, a flow path for fluid from the inlet to the outlet. The system includes a piston mounted in and axially moveable relative to a cylinder, the inlet and outlet defined in the cylinder. The piston has a piston end on which are mounted upper and lower seals and is biased to a first closed position, in which the upper and lower seals define a chamber within the cylinder to retain pressurised fluid from the inlet, the upper seals preventing flow of the fluid from the chamber to the outlet, and wherein an external force applied to the piston moves the upper seals away from sealing engagement with the cylinder.

Abstract: The brake assembly includes a housing, a rotor disc. The rotor disc includes at least one internal cavity. The at least one internal cavity includes a pawl and a thermal fuse. In use, the thermal fuse is configured to maintain the position of the pawl in the at least one internal cavity when a temperature is below a predetermined threshold, and wherein the thermal fuse is configured to melt when a predetermined threshold of temperature is reached during braking to release the pawl out of the at least one internal cavity towards the housing. The housing includes at least one recess configured to receive the pawl.

Abstract: A control mechanism for an aircraft includes: a conversion mechanism having a translatable part and a rotatable part, the translatable part being reversibly translatable and being connectable to an inceptor; an inceptor connector connected to the translatable part of the conversion mechanism; a differential device connected to the rotatable part of the conversion mechanism, the conversion mechanism being configured to reversibly convert translational motion of the inceptor connector to rotational motion of the differential device; an adjustment member connected to the differential device; and a control member connected to the differential device; wherein the differential device is configured such that the adjustment member is maintainable in position during an aircraft control process to permit: translation of the inceptor connector from a translational neutral position; and corresponding movement of the control member, to control the aircraft through the differential device.

Abstract: A method of applying a braided cover to a core comprises braiding a plurality of tows around the core from a plurality of bobbins. One or more properties of the tow on a respective bobbin vary along the length of the tow.

Abstract: A strain gauge assembly includes: a strain gauge comprising a plurality of resistive elements connected as a Wheatstone bridge or half Wheatstone bridge; an excitation signal generator arranged to provide an excitation signal to two resistive elements of the strain gauge; phase shifting circuitry arranged to determine phase shifts in the excitation signal responsive to changes in resistance of the two resistive elements and an end stage configured to output a measure indicative of the phase shift as an indication of strain on the assembly.

Abstract: A pitch change actuation system for varying a propeller blade pitch includes: an actuator body defining an interior volume; and a chamber separator located within the interior volume of the actuator body and dividing the interior volume into a first chamber and a second chamber, the two chambers being fluidly separated by the chamber separator. The first and second chambers are configured to receive hydraulic fluid. The actuator body is configured to translate relative to the chamber separator in response to a difference in hydraulic pressure between the first chamber and second chamber; and the translation of the actuator body is configured to effect a change in propeller blade pitch.

Abstract: A piloting device for piloting an aircraft includes a piloting member suitable for being actuated by a pilot, a mechanism for mounting and guiding in rotation the piloting member about at least one rotation axis with respect to a frame, at least one force sensor connected between the piloting member. The mechanism includes at least one sensing element configured to produce a signal upon deformation indicative of a force applied to the piloting member. The force sensor comprises at least one pair of bearing surfaces. The device also includes at least one pair of stops configured to limit the angular amplitude of rotation of the piloting member with respect to the frame on abutment of the at least one pair of bearing surfaces with at least one pair of stops. The stops or at least one of the bearing surfaces comprises a compliant material.

Abstract: A resistive and locking system for locking rotation of a shaft. The system includes a housing defining an axis AX therethrough. The housing includes a drive shaft mounted in the housing and extending axially from a bottom end of the housing and a first stage comprising a resistive mechanism provided in the housing. The housing also includes a second stage comprising a locking mechanism arranged in the housing above the first stage. The locking mechanism is biased axially to frictionally engage with and lock the first stage mechanism to prevent rotation of the drive shaft, the locking mechanism including a magnetic unlocking mechanism configured to remove the frictional engagement with the first stage on application of power to the locking mechanism.

Abstract: A device for assisting the opening and closing of a door in a structure. The device may comprise: a door shaft configured to rotate about a longitudinal axis thereof in both a first direction and in a second opposite direction, and configured to be mounted to the structure to form a hinge about which the door may rotate in the both the first and second directions relative to the structure; a first actuator linked to the door shaft and configured to control a speed of rotation of the door shaft in the first direction; and a second actuator linked to the door shaft and configured to drive rotation of the door shaft in the second direction. The second actuator is an electromechanical actuator.