Abstract: This invention allows for the precise determination of an aircraft's landing conditions and whether an aircraft has experienced a hard landing that exceeds the allowable design loads of the aircraft's landing gear. The system comprises a computer that measures signals from an inertial measurement unit (IMU) at high data rates (e.g. 100 Hz) and also records signals from the aircraft avionics data bus. The computer compares the output from the inertial measurement unit's accelerometers against at least one predetermined threshold parameter to determine whether the aircraft's three dimensional landing deceleration is safely within the design allowances or other regulatory limitations, or whether the landing event needs further investigation.

Abstract: Aircraft landing gear includes a retractable housing comprising an upper leg (11); a lower leg (15) including a wheel axle (16) slidingly disposed within the upper leg (11) and resiliency biassed to an extended condition; a turning collar (18) rotatably disposed about the housing and having connection means for a drag stay (17); and a steering collar (19) operatively connected to a steering motor (41) and connected to the lower leg (15) by a torque link (21, 22); in which the turning collar (18) is provided with a cam surface (24) which cooperates in use with the torque link (21, 22) to maintain the lower leg (15) with the wheel in the fore-and-aft position when in the extended condition.

Abstract: The invention relates to a method of fabricating a composite material connecting rod, the method comprising the step of cutting out a pattern presenting two opposite edges from a composite fiber fabric made up of a plurality of superposed primary plies that are bonded together in such a manner that the primary plies can slide relative to one another, rolling the pattern into a tube in such a manner that the primary plies slide relative to one another to give a chamfer shape to the two edges, and joining together the chamfer-shaped edges so that they overlap.

Abstract: The invention relates to a method of making at least one stiffener element, the method comprising steps of: cutting out two substantially identical elongate flanks (2, 4) from fiber plates, each flank presenting two lateral projections (10, 14) on either side of a central portion (6); superposing the flanks (2, 4) and stitching them together along two parallel lines (8, 12) that mark the boundaries between the lateral projections and the central portions; and folding the lateral projections (10, 14) along the lines of stitching to either side of the assembly as formed in this way in order to form flanges (22, 24).

Abstract: Apparatus for monitoring a parameter associated with a structural component comprises a module (1) which is attachable to the structural component and which is associated with a sensor (2) for making measurements of said parameter. The module incorporates a power supply (7) for powering the apparatus; a memory (4) for storing data from the sensor, and a processor (3) to process measurement signals from the sensor (2) and to store data in said memory (4). A display (5) for displaying measurements made by the sensor (2) may also be provided. The processor may make use of an algorithm such as a rainflow counting algorithm to reduce data stored. For energy saving, the sensor (2) is only powered on as required to take a measurement. The sensor (3) is interfaced to the processor through a signal processing subsystem (6) consisting of an amplifier and A to D converter, and each is turned on and off as required to power the sensor (2) for measuring.

Abstract: Friction device includes at least two members, one of which is mobile, or potentially mobile, in terms of relative displacement with respect to the other under the action of an external stimulus. The relative displacement is liable to cause the relative displacement of two friction surfaces subjected to pressing forces, so as to convert the external stimulus into a friction force and to thus control the displacement of the mobile or potentially mobile member. The pressing forces are produced by pre-stressing mechanisms and the members are able to act on the effects of the pre-stressing mechanisms so as to use the resultant effect of the relative displacement of the mobile or potentially mobile member to reduce the pressing forces.

Abstract: The present invention is a device that allows the pressure inside an aircraft landing gear shock strut to be measured. A charging valve is modified by integrating a small pressure sensing device into the stem of the part such that the active diaphragm is subjected to the pressure within the charged vessel. The wires from the pressure sensing device are connected to a receptacle or connector in the bore of the stem such that a corresponding electrical receptacle may be mated for the purposes of making a measurement. The internal receptacle is designed such that the flow of air or oil is not excessively impeded and normal servicing tools do not interfere with the receptacle.

Abstract: The invention provides a method of fabricating a lug on a structural element of composite material made at least locally out of a stack of primary plies of composite fibers defining at least one extension for forming the lug. The method includes the step of separating the primary plies at least in the extension and of inserting intermediate plies between the primary plies.

Abstract: This invention allows for the precise determination of an aircraft's landing conditions and whether an aircraft has experienced a hard landing that exceeds the allowable design loads of the aircraft's landing gear. The system comprises a computer that measures signals from an inertial measurement unit (IMU) at high data rates (e.g. 100 Hz) and also records signals from the aircraft avionics data bus. The computer compares the output from the inertial measurement unit's accelerometers against at least one predetermined threshold parameter to determine whether the aircraft's three dimensional landing deceleration is safely within the design allowances or other regulatory limitations, or whether the landing event needs further investigation.

Abstract: The invention provides a method of fabricating a lug on a structural element of composite material made at least locally out of a stack of primary plies of composite fibers defining at least one extension for forming the lug. The method includes the step of separating the primary plies at least in the extension and of inserting intermediate plies between the primary plies.

Abstract: The invention relates to a telescopic shock absorber for an aircraft undercarriage, the shock absorber comprising a strut (1) in which a rod (2) is mounted to slide, the shock absorber including controlled retraction means (41 . . . 43) for retracting the rod into the strut to a retracted position. The shock absorber includes positive retention means (27, 29) for retaining the rod in the strut and adapted to retain the rod in the retracted position when the rod is moved thereto by the retraction means, the positive retention means being arranged, at least in the event of a severe landing of the aircraft, to allow the rod to be pushed into the strut beyond the retracted position.

Abstract: A deep hole boring head is provided which is capable of rotating about a central axis, a body whose front part has at least one cutting edge followed by a recess which leads to a duct inside the body, this duct allowing the chips formed during the boring to be cleared away rearwards, and includes at a front end thereof and at a center portion thereof a pilot drill bit capable of guiding the head during boring. Use for the boring of a production piece is made of titanium, the ratio L/D between the depth L of the hole bored and the diameter D of the latter being greater than or equal to 10, and the diameter D being greater than or equal to 65 mm.

Abstract: A method and apparatus for reducing the noise generated by an aircraft undercarriage when the aircraft is flying and the undercarriage is deployed, includes coating at least a portion of a structural element of the undercarriage in a material that is of lower density than the material of the structural element in order to give this portion an aerodynamic shape suitable for smoothing a stream of air flowing around the portion.

Abstract: The present invention provides a lock sensor for use in an actuator such as is used in aircraft landing gear systems. The lock sensor comprises at least one field emitting device (46) mounted on a locking actuator pressure vessel where the field emitting device (46) monitors the position of at least one target (48). The field emitting device (46) emits a field that when breached by the target sends a signal to indicate that the actuator is in a locked state.

Abstract: The invention relates to a wind-brace device for an aircraft undercarriage, the device comprising a hinged brace movable between a folded position and a stabilization position for stabilizing the undercarriage in the deployed position, a stabilizer member for stabilizing the brace comprising two hinged-together arms, one of the arms having one end hinged to the brace about a hinge axis, and a spring member for urging the arm of the stabilizer member towards the locked position. The spring member is connected to a lever hinged to the brace, the lever presenting a slot in which there is engaged a finger secured to the arm that is hinged to the brace.

Abstract: A semi-levered landing gear for an aircraft comprises a main shock absorber strut (1) connected to the airframe; a bogie beam (4) extending fore and aft of the airframe with forward and aft wheels (J, T) and a main pivot connection (5) to the strut (1) between the forward and aft wheels (7, T) and an auxiliary actuator (49) connected between the strut (1) and the front of the bogie beam (4) at an auxiliary pivot (14). The auxiliary actuator (49) comprises a two stage telescopic hydraulic unit comprising a first stage piston and cylinder actuator (59, 63) and a second stage piston and cylinder actuator (56, 50) operating coaxially within an outer casing (50). A respective piston rod (65, 60) each extends from each end of the casing (50) and is connected to a respective one of said (strut 1) and bogie beam (4). The first stage actuator (59, 63) is operable to an extended position, and the second stage actuator (56, 60) is operable between a retracted position (FIG. 11) and an extended position (FIG.

Abstract: An airplane undercarriage including a shock absorber having first and second portions that are movable relative to each other. The undercarriage further including a first wave transceiver assembly disposed on the first movable portion. The assembly includes a first transmitter for transmitting a first wave towards the second movable portion and a first receiver for receiving the first wave after it has been reflected on an obstacle formed by a mechanical part secured to the second movable portion. The undercarriage also includes an independent second wave transceiver assembly disposed on the first movable portion. The second assembly includes a second transmitter for transmitting a second wave towards the second movable portion, and a second receiver for receiving the second wave after it has been reflected on an obstacle formed by a free surface of a hydraulic fluid contained in the shock absorber or a mechanical part defining the free surface.

Abstract: A damper for an airplane landing gear leg comprises a main strut (11) and a rod piston (13) co-operating with the strut (11) to define a main chamber (15) and annular chamber (16) for hydraulic fluid, and presenting internally two adjacent chambers (19, 20) that are isolated from each other by a separator piston (21). The damper (10) further comprises a first secondary strut (26) telescopically Slidable on the above-mentioned rod piston (13), and a second secondary strut (37) telescopically slidable on the other end of the first secondary strut (26). The two second annular chambers (31, 40) as defined in this way are respectively connected to associated control circuits thus enabling the total length of the damper to be shortened or lengthened respectively for the purpose of causing the landing gear to contract or to be extended.

Abstract: This invention provides a pin assembly that is self-lubricating and includes a pin, a pin insert that is received within the pin and a quantity of lubricating agent. The present invention also provides an insert for a pin that may be used in a pin joint that contains an automatic lubrication dispensing mechanism.

Abstract: Disclosed is an arrangement in which the main landing gear assemblies of a large commercial airplane are each joined to the airplane at four attachment points. Two of the attachment points connect the landing gear side brace and drag brace to the airplane. The two remaining attachment points are aft and forward trunnions that are mounted to the airplane wing. The aft trunnion pivotally connects one side of the landing gear shock strut to the airplane and carries both vertical and torsional loading. The forward trunnion is pivotally connected to the other side of the shock strut by a trunnion link. An actuator is coupled between the shock strut and the trunnion link. When the landing gear is down and locked the actuator is not activated and the trunnion link does not have the rigidity and stiffness required to transfer vertical loads to the forward trunnion.