Patent Description:
Reliable ways to visually detect that an aircraft has experienced a hard landing are limited. Typically, pilots and/or aircraft/maintenance crews will visually inspect the aircraft during a pre-flight walk-around. However, a simple visual inspection may not always reveal whether a hard landing has occurred. When a hard landing is suspected to have occurred, the Flight Data Recorder (FDR) may be analyzed. Such analysis generally requires removing the aircraft from service and represents considerable time for the pilot and/or aircraft/maintenance crews to review the FDR in order to validate that a hard landing was experienced by the aircraft, which may cause significant expenses/financial loss for airline companies and/or aircraft owners.

<CIT> and <CIT> each discloses a hard landing indicator for an aircraft.

Aspects of the invention provide a hard landing indicator according to appended claim <NUM> and a method according to appended claim <NUM>. In an embodiment of the disclosure, a landing gear for an aircraft comprises a hard landing indicator according to appended claim <NUM> and a torque link assembly including an upper torque link and a lower torque link hingedly connected to one another at a common pivot. The upper and lower torque links are displaceable toward one another upon the aircraft experiencing a landing. A hard landing indicator is secured to one of the upper and lower torque links and has a part oriented toward the other one of the upper and lower torque links, the other torque link impacting the part upon the other torque link being displaced toward the hard landing indicator by a hard landing of the aircraft, an impact of the other torque link with the part leaving a visual mark thereon.

According to the presently claimed invention, the hard landing indicator includes a first portion secured to the one of the upper and lower torque links, and a second portion projecting outwardly from the first portion toward a path of displacement of the other torque link to be impacted thereby.

In an embodiment, the first portion includes a main plate and at least one side plate projecting from a side of the main plate away from the other torque link, the second portion projecting outwardly from the at least one of side plate toward the path of displacement of the other torque link, the second portion being transverse to the at least one side plate.

In an embodiment, the hard landing indicator is secured to the lower torque link, the lower torque link having an upper surface, a lower surface and side surfaces extending between the upper and lower surfaces, the main plate abutting the upper surface and the at least one side plate abutting one of the side surfaces of the lower torque link.

In an embodiment, the side surfaces of the lower torque link extend obliquely relative to each other between opposite first and second longitudinal ends of the lower torque link, the at least one side plate of the hard landing indicator being oblique relative to a longitudinal axis of the hard landing indicator.

In an embodiment, the lower torque link includes a recessed region spaced inwardly from the upper surface and between the side surfaces, the recessed region delimited by a recess wall extending inwardly from the upper surface, the hard landing indicator having a projection extending outwardly from an inner surface of the main plate, the projection abutting against the recess wall of the recessed region.

In an embodiment, the second portion of the hard landing indicator is a tab, the tab extending from the at least one side plate toward the path of displacement of the other torque link and being transverse to said side plate.

In an embodiment, the tab has opposite first and second side surfaces and a peripheral surface extending between the first and second side surfaces, a portion of the peripheral surface receiving the impact from the other torque link upon the aircraft experiencing the hard landing.

In an embodiment, the main plate includes at least one flange, the at least one flange extending along a length of the main plate and projecting from an outer surface thereof.

In an embodiment, at least one slot is defined through the at least one flange, the landing gear comprising an attachment means inserted through the slot to attach the hard landing indicator to the one of the upper and lower torque links.

In another aspect, there is provided a hard landing indicator mountable to a landing gear of an aircraft, the landing gear having first and second components displaceable toward each other upon the aircraft experiencing a landing, the hard landing indicator comprising: a first portion securable to the first component of the landing gear; a second portion projecting outwardly from the first portion and oriented toward the second component of the landing gear to be positioned within a path of displacement of the second component toward the first component, the second portion being impacted and marked by the second component upon the second component being displaced by a hard landing of the aircraft.

In an embodiment, the first portion includes a main plate and at least one side plate projecting from a side of the main plate, the second portion projecting outwardly from and being transverse to the at least one side plate.

In an embodiment, the at least one side plate is oblique relative to a longitudinal axis of the hard landing indicator, an acute angle being defined between the at least one side plate and the longitudinal axis.

In an embodiment, the main plate and the at least one side plate are integrally molded with one another.

In an embodiment, the second portion is a tab having opposite first and second side surfaces and a peripheral surface extending between the first and second side surfaces, a portion of the peripheral surface receiving the impact from the second component of the landing gear upon the aircraft experiencing the hard landing.

In an embodiment, at least one slot is defined through the at least one flange for receiving an attachment means to attach the hard landing indicator to the first component of the landing gear.

In an embodiment, the hard landing indicator further comprises a projection extending outwardly from an inner surface of the main plate, the projection abutting against a portion of the first component of the landing gear upon securing the hard landing device thereon.

In another aspect, there is provided a method for installing a hard landing indicator on a landing gear of an aircraft, the landing gear including first and second components hingedly connected to one another and displaceable towards each other, the method comprising: securing a first portion of the hard landing indicator on the first component of the landing gear to position a second portion of the hard landing indicator projecting outwardly from the first portion within a path of displacement of the second component of the landing gear toward the first component, the second portion being impacted and marked by the second component upon the second component being displaced by a hard landing of the aircraft.

In an embodiment, securing the first portion includes preventing the hard landing indicator from being displaced along the first component of the landing gear.

In an embodiment, preventing the hard landing indicator from being displaced includes preventing the hard landing indicator from being displaced along a length of the first component.

In an embodiment, preventing the hard landing indicator from being displaced includes preventing the hard landing indicator from being displaced along a width of the first component.

In an embodiment, preventing the hard landing indicator from being displaced along the length of the first component includes abutting a portion of the hard landing indicator against a wall of the first component delimiting a recessed area of the hard landing indictor.

In an embodiment, securing the first portion of the hard landing indicator on the first component includes wrapping an attachment means at least partially about the first portion and about the first component of the landing gear, and tightening the attachment means to immovably secure the hard landing indicator to the first portion of the landing gear.

In an example not covered by the presently claimed invention, there is provided a method of observing a landing gear of an aircraft, the method comprising: verifying visually a hard landing indicator secured to a first component of the landing gear for a visible marking on the hard landing gear, the visible marking being indicative of a hard landing of the aircraft and caused by an impact of a second component of the landing gear with the hard landing indicator due to a pivotable displacement of the second component toward the first component during the hard landing of the aircraft.

In a further example, the method further comprises concluding an absence of the hard landing of the aircraft when the visible marking is absent from the hard landing indicator.

It is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible, the scope of protection being nevertheless defined by the appended claims.

Embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying figures in which:.

Referring to the drawings and more particularly to Fig. <NUM>, an aircraft is shown at <NUM>, and is generally described to illustrate some components for reference purposes in the present disclosure. The aircraft <NUM> has a fuselage <NUM> having a fore end and an aft end, with a cabin generally located between the cockpit and the tail assembly. A tail assembly comprises a vertical stabilizer <NUM> with a rudder, and horizontal stabilizers <NUM> with elevators. The tail assembly has a fuselage-mounted tail, but other configurations may also be used for the aircraft <NUM>, such as cruciform, T-tail, etc. Wings <NUM> project laterally from the fuselage <NUM>. The aircraft <NUM> has engines <NUM> supported by the wings <NUM> in the depicted embodiment, although for other aircraft they can be mounted to the fuselage <NUM>. The aircraft <NUM> also has landing gears <NUM>, shown schematically in Fig. <NUM>. The aircraft <NUM> is shown as a jet-engine aircraft, but may also be a propeller aircraft. It is also understood that the aircraft <NUM> can be a business aircraft, alternately it can be any other type of aircraft, manned or unmanned, including, but not limited to, a commercial aircraft or a military aircraft.

Referring to Figs. <NUM> to <FIG>, one type of landing gear <NUM> for the aircraft <NUM> includes a torque link assembly <NUM> and a strut shock <NUM>. The torque link assembly <NUM> may include a first component <NUM> and a second component <NUM> hingedly connected to one another. In the depicted embodiment, the first component is a lower torque link <NUM> and the second component is an upper torque link <NUM>. The lower torque link <NUM> and the upper torque link <NUM> are hingedly connected to one another and displaceable toward one another upon the landing gear <NUM> experiencing a landing.

The lower and upper torque links <NUM>, <NUM> are connected together at one of their respective ends. A hinge 23A is defined between the lower and upper torque links <NUM>, <NUM>. The hinge 23A includes an axle <NUM> and openings 23B in adjacent ends of the lower and upper torque links <NUM>, <NUM>. The axle <NUM> extends through the openings 23B to connect the lower and upper torque links <NUM>, <NUM> to one another at their respective ends and implements a common rotating axis such that the lower and upper torque links <NUM>, <NUM> may angularly displace towards and away from one another in a scissor-like fashion (i.e. as the blades of a scissor typically do). The lower and upper torque links <NUM>, <NUM> are pivotable about the axis defined by the axle <NUM> towards and away from each other. The axle <NUM> is mounted in the openings 23B with or without an additional bearing (e.g. slide bearing, ball bearings, etc.) to facilitate rotation of the axle <NUM> and in turn the scissor-like movement of the lower and upper links <NUM>, <NUM>.

The lower torque link <NUM> and/or the upper torque link <NUM> have a first surface <NUM> defined by a first wall, which may be an upper surface or upper wall, a second surface <NUM> defined by a second wall, which may be a lower surface or lower wall, and opposite third and fourth surfaces <NUM>, <NUM>, which may be opposite side surfaces or opposite side walls. The following description is of the lower torque link <NUM>, it being understood that the upper torque link <NUM> has similar features to these described hereafter. The lower torque link <NUM> in the depicted embodiment includes a recessed region <NUM> spaced inwardly from the first surface <NUM> and between the third and fourth surfaces <NUM>, <NUM>. The recessed region <NUM> is delimited by a recess wall <NUM> extending inwardly from the first surface <NUM>. The recess wall <NUM> circumscribes the recessed region <NUM>. The presence of the recess <NUM> helps to reduce the weight of the lower torque link <NUM>, and thus of the torque link assembly <NUM>. The surfaces <NUM>, <NUM>, <NUM>, <NUM> are planar surfaces (partially or entirely planar) in the depicted embodiment, and in alternate embodiments they may include portions with irregular reliefs. As shown in <FIG>, the opposite side surfaces <NUM>, <NUM> extend obliquely relative to each other between opposite first and second longitudinal ends of the lower torque link <NUM>. Each of the side surfaces <NUM>, <NUM> extend in directions that diverge away from the hinge axle <NUM>. The side surfaces <NUM>, <NUM> are not parallel to one another. An acute angle is defined between the side surfaces <NUM>, <NUM>. An acute angle B is also defined between the side surfaces <NUM>, <NUM> and a longitudinal axis B-B of the lower torque link <NUM>. Stated differently, side surfaces <NUM>, <NUM> each extend between both ends of the lower torque link <NUM> in non-parallel directions, such that, viewed from the top, the lower torque link <NUM> is wider at one longitudinal end than at its other longitudinal end. In other words, side surfaces <NUM>, <NUM> of the lower torque link <NUM> extend such that their respective planes converge toward a common point. The lower or upper torque link <NUM>, <NUM> may be shaped differently in other embodiments.

The lower and upper torque links <NUM>, <NUM> are connected at another one of their respective ends to portions of the landing gear <NUM>. Referring to Fig. <NUM>, the lower torque link <NUM> is connected to a strut shock movable portion <NUM>, which may be a piston of the strut shock <NUM>. The lower torque link <NUM> in Fig. <NUM> is connected to a wheel mounting axle assembly <NUM> to which wheels of the landing gear <NUM> are secured. The upper torque link <NUM> is connected to a stationary shock strut cylinder <NUM> of the strut shock <NUM>. In an alternate embodiment, the upper torque link <NUM> is connected directly to another supporting structure of the landing gear <NUM>.

During a landing, the wheels and the wheel mounting axle assembly <NUM> connected to the movable portion <NUM> of the strut shock <NUM> move vertically upward and their movement is absorbed within the shock strut cylinder <NUM> to reduce a vertical acceleration of the aircraft <NUM>. Since the lower and upper torque links <NUM>, <NUM> are connected to respective portions of the strut shock <NUM> and hingedly connected to one another, a relative vertical movement between the strut shock movable portion <NUM> and the stationary shock strut cylinder <NUM> results in a compressed state of the strut shock <NUM> causing the lower and upper torque links <NUM>, <NUM> to pivot towards each other. As such, a space (i.e. a generally triangular space) defined between the lower and upper torque links <NUM>, <NUM> diminishes. Stated differently, and referring to <FIG>, an angle A between the lower and upper torque links <NUM>, <NUM> is reduced as they pivot toward each other. It will therefore be appreciated that the pivoting displacement of the lower and upper torque links <NUM>, <NUM> is a relative displacement, in that the lower and upper torque links <NUM>, <NUM> are brought closer together by either one or both of the lower and upper torque links <NUM>, <NUM> experiencing displacement.

As the lower and upper torque links <NUM>, <NUM> pivot toward each other, the side surface <NUM>, <NUM> of the upper torque link <NUM> is brought closer to the a corresponding side surface <NUM>, <NUM> of the lower toque link <NUM>. During initial pivoting displacement of the lower and upper torque links <NUM>, <NUM> toward each other, the adjacent side surfaces <NUM>, <NUM> do not interfere with each other. After further displacement, the side surfaces <NUM>, <NUM> scissor very close to one another and may even contact one another. It will thus be appreciated, and as further described below, that an object positioned in this path of displacement of the lower and upper torque links <NUM>, <NUM> toward each other will be impacted by one of the torque links <NUM>, <NUM>.

In certain situations, the aircraft <NUM> may experience a "hard" landing. A hard landing is not a typical landing of the aircraft <NUM>. It is usually an exceptional occurrence and corresponds to a landing during which a vertical acceleration threshold of the aircraft <NUM> is exceeded. When a hard landing occurs, the strut shock <NUM> may compress more than it would during a standard or normal landing. For example, the distance over which the strut shock <NUM> may compress during a hard landing may be greater than <NUM> inches, in some cases as much as <NUM> inches, depending on the types of landing gear, the landing gear arrangement and/or types of aircraft. In contrast, and again as an example, when no hard landing is experienced and thus a normal landing of the aircraft <NUM> occurs, the strut shock <NUM> may compress a distance of only <NUM> inches. In some cases, a hard landing of the aircraft <NUM> may result in structural damage to portions of the landing gear <NUM> or other portions of the aircraft <NUM>.

If pilots and/or maintenance crews suspect that a hard landing occurred, they may visually inspect the aircraft during a walk-around to visually detect any structural damage caused by the potential hard landing. Relying on a pilot's or maintenance crew's experience to determine when a hard landing has occurred may result in judgment errors. For instance, the pilot may incorrectly determine that no hard landing had occurred when there actually was one, which may result in flight of an aircraft which is not flightworthy. Conversely, the pilot may incorrectly determine that a hard landing has occurred, which may lead to unnecessary maintenance assessments and flight delay. From time to time, for greater certainty, pilots and/or maintenance crews may have to review and analyze the Flight Data Recorder (FDR) to determine whether a hard landing actually occurred. However, this may be time consuming and incur huge expenses for the airliner companies and/or the aircraft owner(s).

Disclosed herein is a device and a method for detecting a hard landing of the aircraft <NUM> visually and easily that may be applicable to various types of landing gears <NUM>.

Referring to Figs. <NUM> and <FIG>, a hard landing indicator <NUM> is shown mounted and secured to the landing gear <NUM>. The indicator <NUM> may be attached to the main or the nose landing gear <NUM> of the aircraft <NUM>. As will be explained in greater detail below, the hard landing indicator <NUM> provides a visible indication of a hard landing of the aircraft <NUM>. This visible indication can be viewed by a pilot and/or maintenance crew during their visual inspection of the aircraft <NUM>, and will indicate to them that a hard landing of the aircraft <NUM> occurred. The hard landing indicator <NUM> is secured to a component of the landing gear <NUM>. In the depicted embodiment, the hard landing indicator <NUM> is secured to one of the upper and lower torque links <NUM>, <NUM> of the torque assembly <NUM>. In alternate embodiments of the landing gear, the hard landing indicator <NUM> may be secured to other components. For example, in the embodiment where the landing gear <NUM> is a "trailing arm" type landing gear, the hard landing indicator <NUM> may be secured to a portion of the trailing arm, for instance.

<NUM> and <FIG> show an embodiment of the hard landing indicator <NUM>. The hard landing indicator <NUM> has a base or first portion <NUM> securable to the first component of the landing gear <NUM> such as the lower torque link <NUM>, and a second portion <NUM> projecting outwardly from the first portion <NUM>. The second portion <NUM> projects outwardly from the first portion <NUM> toward a path of displacement of the upper torque link <NUM> toward the lower torque link <NUM>. As such, the second portion <NUM> is positioned such that the side surface <NUM>, <NUM> of the upper torque link <NUM> of the landing gear <NUM> will impact the second portion <NUM> during a hard landing of the aircraft <NUM> when the upper torque link <NUM> is displaced toward the lower torque link <NUM>. As a result of this impact, the upper torque link <NUM> will leave a visual and visible mark on the second portion <NUM> of the hard landing indicator <NUM>. In an alternate embodiment, the first portion <NUM> of the hard landing indicator <NUM> is secured to the upper torque link <NUM>, and the second portion <NUM> is positioned to receive an impact from the lower torque link <NUM> in the case of a hard landing. In other embodiments, the first and second components of the landing gear <NUM> may be parts of a trailing arm landing gear, such as the trailing arm itself, the structural post and/or other structural bracings of the trailing arm landing gear.

The first and second portions <NUM>, <NUM> of the hard landing indicator <NUM> may take different forms. <NUM> and <FIG>, the first portion <NUM> includes a main plate <NUM> and at least one side plate <NUM> projecting from a side of the main plate <NUM>. When mounted on one of the lower and upper torque links <NUM>, <NUM>, the main plate <NUM> abuts the upper surface <NUM> of the torque link <NUM>, <NUM>, and the side plate <NUM> abuts one of the side surfaces <NUM>, <NUM> of the torque link <NUM>, <NUM>. The side plate <NUM> is transverse to the main plate <NUM>. The side plate <NUM> has an orientation which is non-parallel to the longitudinal axis A-A of the hard landing indicator <NUM>. The orientation of the side plate <NUM> conforms to the obliquely extending side surface (<NUM> or <NUM>) of the torque link <NUM>, <NUM> against which the side plate <NUM> abuts. For instance, the side plate <NUM> may lie in a plane that intersects the longitudinal axis A-A and is non-parallel or oblique to the longitudinal axis A-A. The angle between the plane defined by the side plate <NUM> and the longitudinal axis A-A is substantially the same acute angle as that between the side surface <NUM>, <NUM> and the longitudinal axis B-B of the lower torque link <NUM>, discussed above.

As better shown in <FIG>, the first portion <NUM> includes a pair of opposite side plates <NUM> projecting from spaced-apart sides of the main plate <NUM>. Each one of the side plates <NUM> abuts one of the side surfaces <NUM>, <NUM> of the torque link <NUM>, <NUM>. The pair of side plates <NUM> extend obliquely relative to each other to conform to the obliquely extending side surfaces <NUM>, <NUM>. As shown, a first one of the side plates <NUM> includes the second portion <NUM> of the hard landing indicator <NUM>, and a second one of the side plates <NUM> is substantially smaller than the first one of the side plates <NUM>. The second one of the side plates <NUM> may be referred to as a lip for abutting against the other side surface <NUM>, <NUM> not already abutted against by the first one of the side plates <NUM>. In some variants, the second one of the side plates <NUM> may be the same size as the first one of the side plates <NUM> (or substantially the same size). The hard landing indicator <NUM> may also be mounted differently. For instance, the main plate <NUM> may abut the lower surface <NUM> of the torque link on which it is mounted, and the side plate <NUM> may abut one of the side surfaces <NUM>, <NUM> of the torque link. As such, the hard landing indicator <NUM> may be mounted under the upper torque link <NUM>, for instance, and may still have its second portion <NUM> projecting outwardly toward the path of displacement of the upper torque link <NUM>.

Still referring to Figs. <NUM> and <FIG>, the main plate <NUM> includes one or more flanges <NUM>. Each flange <NUM> extends in a direction substantially parallel to the longitudinal axis A-A of the hard landing indicator <NUM> and projects from an outer surface of the main plate <NUM>. One or more slots <NUM> are defined through each flange <NUM>. The slots <NUM> are shaped and sized to receive an attachment means <NUM> (see <FIG> for an example), such as a zip tie, a strap with a strap lock, a band, etc., to attach the hard landing indicator <NUM> to the landing gear <NUM> (i.e. to secure the hard landing indicator <NUM> on one of the torque links <NUM>, <NUM>). In Fig. <NUM>, each flange <NUM> has two slots <NUM>, each shaped and sized to receive its own attachment means <NUM>. In alternate embodiments, the slots <NUM> may be grooves defined in the flanges <NUM>, such that the slots <NUM> are open at one end (instead of being holes through the flanges <NUM>). This may facilitate engagement of the attachment means <NUM> in the slots <NUM> and still help to keep the attachment means <NUM> in place on the main plate <NUM>.

<NUM> and <FIG>, a first flange <NUM> and a second flange <NUM>' are present on the main plate <NUM>. The second flange <NUM>' may or may not extend parallel to the first flange <NUM>, such that the second flange <NUM>' may be disposed obliquely (i.e. at angle) relative to the first flange <NUM>. In some cases, the flanges <NUM>, <NUM>' form elongated ribs which help to rigidify the main plate <NUM>. The elongated rib may be straight (i.e. partially or entirely straight) and/or have a profiled shape including curved portions. The second flange <NUM>' may or may not include a slot <NUM>. Where the second flange <NUM>' includes such slot(s) <NUM>, the attachment means <NUM> may also pass through said slots <NUM> in the second flange <NUM>'. The slots <NUM> may prevent the attachment means <NUM> from slipping off the hard landing indicator <NUM> during operation when the hard landing indicator <NUM> is secured onto the landing gear <NUM> with the attachment means <NUM>. In an alternate embodiment, instead of attaching the hard landing indicator <NUM> on the landing gear <NUM> with separate attachment means <NUM> such as zip ties, the attachment means <NUM> are an integral part of the hard landing indicator <NUM>, for instance an integral part of the main pate <NUM> and/or at least one of the side plates <NUM>. This may reduce the number of separate parts and facilitate handling and installation of the hard landing indicator <NUM> on the landing gear <NUM>. For instance, in an embodiment, the attachment means <NUM> includes an elongated extension of the side plate <NUM> wrapping at least partially about the component of the landing gear <NUM> (e.g. wrapping about one of the torque links <NUM>, <NUM>). In addition to or instead of the mechanical attachment means <NUM>, the hard landing indicator <NUM> may be adhesively bonded to the component of the landing gear <NUM>, for instance adhesively bonded to either one of some of the upper surface <NUM> and side surfaces <NUM>, <NUM> of the torque link (<NUM>, <NUM>). In some cases, although the attachment means <NUM> may include an elongated extension of the side plate <NUM> wrapping at least partially about the component of the landing gear <NUM>, adhesively or not bonded to the component of the landing gear <NUM>, the attachment means <NUM> may additionally include zip ties (or similar), as discussed above. This may provide an additional level of safety when securing the hard landing indicator <NUM> to the landing gear <NUM>.

<FIG> and <FIG> show the hard landing indicator <NUM> positioned on the lower torque link <NUM>. The hard landing indicator <NUM> has a stud, peg, knob or projection <NUM> extending outwardly from an inner surface of the main plate <NUM>. Dimensions and shapes of the projection <NUM> may vary as required. For example, in the depicted embodiment, the projection <NUM> is cylindrical and extends from the inner surface of the main plate <NUM>. The projection <NUM> may have any other suitable shape in other embodiments. Upon installing the hard landing indicator <NUM> on the lower torque link <NUM>, the hard landing indicator <NUM> is displaced until the projection <NUM> abuts against the recess wall <NUM> of the recessed region <NUM>. As such, when the hard landing indicator <NUM> is mounted on the lower torque link <NUM> at the location it is intended to be installed, the projection <NUM> may prevent movement of the hard landing indicator <NUM> along the lower torque link <NUM> in a direction that extends along the longitudinal axis B-B of the lower torque link <NUM> toward the hinge 23A. In other words, when the projection <NUM> engages the recess wall <NUM>, the hard landing indicator <NUM> is restricted from moving longitudinally along the longitudinal axis B-B of the lower torque link <NUM> toward the hinge 23A. The projection <NUM> may thus act as a positioning means to position the hard landing indicator <NUM> on the component of the landing gear <NUM>.

Referring to <FIG>, the second portion <NUM> of the hard landing indicator <NUM> includes, or is the form of, a tab 42A. The tab 42A extends from one of the side plates <NUM> and is transverse to the side plate <NUM>. The tab 42A may have different shapes. In the embodiment shown in <FIG>, the tab 42A has opposite first and second side surfaces <NUM> and a peripheral surface <NUM>. During a hard landing of the aircraft <NUM>, as the upper torque link <NUM> is displaced toward the lower torque link <NUM>, the upper torque link <NUM> impacts the peripheral surface <NUM> of the tab 42A and leaves a visible marking <NUM> (see <FIG>). If the visible marking <NUM> is not present on the tab 42A, then it can be concluded that a hard landing of the aircraft <NUM> did not occur. During most landings of the aircraft <NUM>, the upper torque link <NUM> will not impact the peripheral surface <NUM> of the tab 42A and leave the visible marking <NUM>. In an embodiment, the tab 42A may have a thin and elongated body shaped as a fin. The tab 42A may extend outwardly from one of the side plates <NUM> transversally to the longitudinal axis A-A of the main plate <NUM> (see Fig. <NUM>). A cross-sectional shape of the tab 42A may vary along a height of the tab 42A.

Referring to Fig. <NUM>, the peripheral surface <NUM> may include a first and a second flat portions <NUM><NUM>, <NUM><NUM> extending transversally from each other, forming a projecting corner <NUM><NUM>, and an inwardly curved portion <NUM><NUM> extending from the second flat portion <NUM><NUM> and forming an apex <NUM><NUM> before extending toward the side plate <NUM>. In other embodiments, the tab 42A may take different shapes. The shape of the tab 42A may be selected to offer enough strength to prevent fragmentation and thus avoid detachment of broken fragments of the tab 42A to be left on the tarmac after landing, to ensure robustness of the tab 42A, and/or to ensure the visible marking <NUM> be easily witnessed by an observer.

Referring to <FIG> and <FIG>, the second portion <NUM>, which receives the impact from the component of the landing gear <NUM> in the case of a hard landing, is not frangible, such that the second portion <NUM> should not detach or shear from the remainder of the hard landing indicator <NUM> upon receiving the impact resulting from a hard landing. As such, the second portion <NUM>, for instance the tab 42A, may be irreversibly deformed upon being impacted, whereby the visible marking <NUM> due to the impact may take the form of a notch or divot in the peripheral surface <NUM> of the tab 42A. In an alternate embodiment, the visible marking <NUM> may be in the form of a line or scratch in the peripheral surface <NUM>. In an embodiment, the second portion <NUM> has a bright colour such as yellow or white. It is expected that the hard landing indicator <NUM> will be covered in dirt and grease during operation of the aircraft because of its location on the landing gear <NUM>. In the embodiment where the second portion <NUM> has the bright colour, the visible marking <NUM> created by the impact will form a line, scratch, divot, notch, etc. that is brighter than adjacent portions of the dirty second portion <NUM> and thus be more clearly visible. It will therefore be appreciated that the visible marking <NUM> left on the second portion <NUM> by the component of the landing gear <NUM> does not disturb or alter the structural integrity of the second portion <NUM> or the hard landing indicator <NUM>, and does not result in portions of the hard landing indicator <NUM> being broken off or separate from a remainder of the hard landing indicator <NUM>. This contrasts with some conventional devices, whose impacted parts displace, break, or are torn off from the remainder of the device.

In an embodiment, the hard landing indicator <NUM> may be made entirely or partially of a thermoplastic material, for example Polytetrafluoroethylene (PFTE). Other materials may be used, such as other polymeric materials (e.g. nylons). At least the second portion <NUM> may be made from such a material. Such a plastic second portion <NUM> may be more easily deformable/markable upon being impacted by the component of the landing gear <NUM>, which is typically made of a rigid material such as an metal alloy (e.g. aluminium allow, titanium alloy, metal alloy, etc.). The hard landing indicator <NUM> may be injection molded as a single piece, such that, for example, the main plate <NUM> and the side plates <NUM> may be integrally molded to one another, which may reduce manufacturing costs and render it easily to manufacture. Other materials and/or manufacturing method may be used to manufacture the hard landing indicator <NUM>. The material(s) used for manufacturing the hard landing indicator <NUM> may be selected for their capacity to withstand degradation from chemical products, such as oil or other hydraulic fluids of the aircraft <NUM> and landing gear <NUM> and/or able to withstand extreme temperature ranges.

Referring to <FIG> and <FIG>, there is disclosed a method for installing the hard landing indicator <NUM> on the landing gear <NUM>. The method includes securing the first portion <NUM> of the hard landing indicator <NUM> on the first component of the landing gear <NUM> to position the second portion <NUM> of the hard landing indicator <NUM> such that it may project outwardly from the first portion <NUM> within the path of displacement of the second component of the landing gear <NUM> toward the first component of the landing gear <NUM>. More particularly, in an embodiment where the first portion <NUM> includes the main plate <NUM> and side plate <NUM>, securing the first portion <NUM> includes positioning the first portion <NUM> such that the main plate <NUM> abuts against the upper surface of the lower torque link and the side plate <NUM> abuts on the side surface <NUM> of the lower torque link <NUM>. In the embodiment where the hard landing indicator <NUM> includes opposite first and second side plates <NUM>, securing the first portion <NUM> includes positioning the first portion <NUM> such that the first one of the side plates <NUM> abuts against one of the side surfaces <NUM>, <NUM> of the torque link <NUM> and the second one of the side plates <NUM> (e.g. the lip) abuts against the other one of the side surfaces <NUM>, <NUM>. Stated differently, the main plate <NUM> and the pair of opposite side plates <NUM> straddle respectively the upper surface <NUM> and first and second side surfaces <NUM>, <NUM> of the lower torque link <NUM>. As the pair of opposite side plates <NUM> may have the same acute angle B relative to the longitudinal axis A-A of the hard landing indicator <NUM> as that of the side surfaces <NUM>, <NUM> relative to the longitudinal axis B-B of the lower torque link <NUM>, movement in a direction along the longitudinal axis B-B of the lower torque link <NUM> is prevented when the first portion <NUM> is positioned where it is intended on the lower torque link <NUM>. In other words, when positioned on the torque link <NUM>, the hard landing indicator <NUM> may be restricted from sliding in the direction where the side surfaces <NUM>, <NUM> of the torque link <NUM> diverge from one another. The pair of obliquely opposite side plates <NUM> of the hard landing indicator <NUM> may therefore act as a positioning means to position the hard landing indicator <NUM> on complementary surfaces of a landing gear <NUM>.

In an embodiment, where the hard landing indicator <NUM> has the projection <NUM> discussed above, positioning the hard landing indicator <NUM> further includes engaging the projection <NUM> in the recessed region <NUM> of the torque link <NUM>, <NUM>. As such, the hard landing indicator <NUM> is prevented from moving in a direction extending along the longitudinal axis B-B of the torque link <NUM>, <NUM>. In embodiments where the hard landing indicator <NUM> includes only one oblique side plate <NUM> and the projection <NUM>, the hard landing indicator <NUM> may be positioned on the torque link <NUM>, <NUM> at a specific location, by locating where the single oblique plate <NUM> may abut against one of the side surfaces <NUM>, <NUM> of the torque link <NUM>, <NUM> and where the projection <NUM> may abut against the recess wall <NUM>. When the hard landing indicator <NUM> is installed in this location, this may cause the hard landing indicator <NUM> to be located at one end of the recessed region <NUM>, adjacent one longitudinal end of the torque link <NUM>, <NUM>, in a state where it may no longer substantially move along the longitudinal axis B-B of the torque link <NUM>, <NUM>.

More particularly, the single side plate <NUM> prevents the hard landing indicator <NUM> from moving in a direction along the longitudinal axis B-B extending away from the hinge 23A of the torque link assembly <NUM>, and the projection <NUM> prevents the hard landing indicator <NUM> from moving in a direction along the longitudinal axis B-B toward the hinge 23A. In an embodiment, this may provide an efficient way to position the hard landing indicator <NUM> at a predetermined place on the torque link <NUM>, <NUM> in the correct orientation, such that the second portion <NUM> is positioned in the path of displacement of the other torque link <NUM>, <NUM> to be impacted thereby during a hard landing. These positioning means, including at least one oblique side plate <NUM> and the projection <NUM>, may thus prevent incorrect installation of the hard landing indicator <NUM> or its movement during operation of the landing gear <NUM> and/or aircraft <NUM>. In this location, the hard landing indicator <NUM> may then be attached using the attachment means <NUM>. In embodiments where the attachment means <NUM> are zip ties, the zip tie(s) may be engaged within the slot(s) <NUM> of the flange(s) <NUM> and wrapped about the torque link <NUM>, <NUM>, or a portion of the torque link <NUM>, <NUM>. The attachment means <NUM> may then be tightened, so that the hard landing indicator <NUM> may be immovably secured to the landing gear <NUM>.

After having experienced a hard landing of the aircraft, the second portion <NUM> of the hard landing indicator <NUM>, which may be or include the tab 42A discussed above, will have been marked with the visible marking <NUM>. The visible marking <NUM> indicates to an observer that a hard landing occurred and that the aircraft <NUM> should be serviced and inspected for possible structural damages. More particularly, detecting a hard landing of the aircraft <NUM> may comprise visually observing the visible marking <NUM> on the hard landing indicator <NUM> caused by the impact of a second component of the landing gear <NUM> with the hard landing indicator <NUM>. Before putting the aircraft <NUM> back in service, the marked hard landing indicator <NUM> may be removed from the landing gear <NUM> (e.g. by cutting or otherwise removing the attachment means <NUM>) and replaced by an unaffected (i.e. new and/or undeformed and/or unmarked) hard landing indicator <NUM>. The installation procedure may thus be repeated.

The above description is meant to be by way of example only, and one skilled in the art will recognize that changes may be made to the embodiments described. Modifications will be apparent to those skilled in the art, in light of a review of this disclosure.

Claim 1:
A hard landing indicator (<NUM>) mountable to a landing gear (<NUM>) of an aircraft, the landing gear comprising first and second components (<NUM>, <NUM>), each of the first and second components (<NUM>, <NUM>) having adjacent first and second side surfaces (<NUM>, <NUM>), the first and second components (<NUM>, <NUM>) being displaceable toward each other in a scissor-like manner upon the aircraft experiencing a landing, the hard landing indicator (<NUM>) comprising:
a first portion (<NUM>) securable to the first component (<NUM>) of the landing gear; and
a second portion (<NUM>) projecting from the first portion (<NUM>) so as to be positioned within a path of displacement of the second component (<NUM>) toward the first component (<NUM>), the second portion (<NUM>) being impacted and marked by the second component (<NUM>) upon the second component (<NUM>) being displaced by a hard landing of the aircraft.