Immobilization system for immobilizing an aircraft, use thereof, and aircraft runway provided with such an immobilization system

Abstract

The invention relates to a system, housed in a pit in an aircraft runway, comprising at least one immobilizing member (1) which comprises a framework (2) that is fixed relative to the walls of the pit, a receiving mat (3) intended to receive landing gear of the aircraft, drive means (4) for driving this mat relative to the framework, braking means (5) for braking this mat, and control means (8) able to activate the drive means in response to a first signal, then deactivate the drive means while activating the braking means in response to a second signal. The system according to the invention provides for the immobilization of an aircraft in difficulty without significant stresses being exerted on this aircraft, which remains in perfect flying condition. The invention makes it possible to do away with any subsequent operation for checking the integrity of the aircraft structure. Moreover, the invention makes it possible to avoid any technical unavailability of the runway. Lastly, the invention is applicable to the immobilization of aircraft during both the landing phase and the take-off phase thereof.

Description

[0001] Aircraft immobilization system, its use, and airfield equipped with such an immobilization system

[0002] Technical field of the invention

[0003] The invention relates to the technical field of aeronautics, particularly civil but also military. More specifically, it concerns the immobilization of aircraft experiencing difficulties while traveling on an airstrip. More precisely, the invention first relates to an aircraft immobilization system, as well as the use of such a system. It also relates to an airstrip equipped with at least one such immobilization system, enabling the aircraft to be stopped while preserving its mechanical integrity and the physical safety of the passengers.

[0004] State of the art

[0005] There are approximately 4,000 commercial airports worldwide, most of which have multiple runways. Each runway is theoretically designed, particularly in terms of length, to allow for the safe landing and subsequent stopping of each aircraft. However, it is understood that malfunctions can occur, preventing the aircraft from coming to a complete stop at the end of the runway. Such malfunctions are often related to mechanical failures, especially in the braking system or in certain moving parts such as slats or flaps. Adverse weather conditions or pilot error can also cause an aircraft to veer off the runway.

[0006] To prevent aircraft from colliding head-on with structures beyond the end of the runway, which could be catastrophic for the occupants, state-of-the-art technology has long provided devices for the emergency immobilization of such aircraft. These include rudimentary systems using a cable or barrier placed across the runway, which slows and then stops the aircraft in distress. A cable system, not used for passenger aircraft, is primarily employed on aircraft carriers. Arresting barriers are deployed by the military to immobilize light aircraft such as fighter jets.

[0007] To ensure the effective immobilization of a distressed aircraft, a system known as an "arresting bed" is used. This is an acronym for Engineered Material Arresting System (EMAS). Such an arresting bed, located beyond the runway threshold, consists of a substantial layer of ballast covered with several centimeters of crushed concrete. When a distressed aircraft impacts this unstabilized structure, its kinetic energy is absorbed, bringing it to a complete stop.

[0008] While this solution proves generally effective, guaranteeing aircraft arrest in the vast majority of circumstances, it does have significant drawbacks. Indeed, it involves severe damage to the aircraft, which is immobilized using the arresting bed described above.

[0009] In essence, when an aircraft is brought to a stop by an arresting gear, it first suffers at least some damage to its fuselage, requiring a very long period of grounding. In most cases, there is also major damage or even breakage of the landing gear, whether main and / or auxiliary. This damage or breakage necessitates the immediate replacement of the affected mechanical parts, which entails a cost of several million euros.

[0010] Furthermore, in the case of aircraft with low-ground-clearance turbofan engines, there is a significant risk of ingestion of foreign objects, such as fragments of concrete, ballast, or other projectiles. It is then generally necessary to replace these turbofan engines, at a cost that can reach tens of millions of euros.

[0011] Also worth mentioning is the risk of the wings striking the ground if the aircraft rolls over due to a landing gear failure. Furthermore, it is generally necessary to replace numerous parts, including radio communication, radio navigation, and radio altimeter antennas, as well as probes, cargo bay doors, and inspection hatches.

[0012] It should be noted that the mechanical damage listed above corresponds to an optimistic scenario in which the aircraft will be able to operate again, subject to extensive repairs. Conversely, in a pessimistic scenario, the aircraft will be completely scrapped after being immobilized by a crash bed.

[0013] Besides the damage to the aircraft itself, the use of an arresting bed creates other logistical problems for the airport. First, the airport must be able to move the aircraft, immobilized in the arresting bed, using one or two heavy-duty cranes. These cranes must be operational quickly to avoid prolonged runway closures. In any case, air traffic management must then be implemented with the runway operating in a degraded mode, or even closed, until the arresting bed is repaired. Furthermore, if the airport has only one runway, it is necessary to organize the diversion of all aircraft to other aprons.

[0014] We know of several documents that deal with devices for immobilizing an aircraft. CN 102 198 864 teaches how to rotate a conveyor belt in the opposite direction to the aircraft's forward movement during landing. CN 107 933 945 describes an immobilization device for an aircraft carrier, the structure of which projects upwards from the carrier's main landing surface. FR 2 762 291 concerns the landing of an aircraft on a floating structure, such as an aircraft carrier. Finally, CN 109 159 907 concerns an aircraft carrier equipped with an immobilization device whose braking tracks are driven in the opposite direction to the aircraft's forward movement.

[0015] The solutions described in the documents above are unsatisfactory for the following reasons. First, CN 107 933 945, FR 2 762 291, and CN 109 159 907 disclose devices that, as they stand, cannot be integrated into the runway pit of an aerodrome or airport. Furthermore, the various devices described in these earlier documents do not allow for the optimal immobilization of an aircraft facing a critical situation.

[0016] In view of the foregoing, one objective of the present invention is therefore to remedy, at least partially, the disadvantages of the prior art mentioned above.

[0017] Another objective of the invention is to provide a system which, while ensuring reliable immobilization of an aircraft in distress, preserves the mechanical integrity of that aircraft.

[0018] Another objective of the invention is to offer such a system which causes little or no disruption to the overall logistics of the airport or airfield which is equipped with it.

[0019] Another objective of the invention is to provide such a system that allows an aircraft in distress to be immobilized not only during its landing phase, but also during its takeoff process. Objects of the invention

[0020] According to the invention, at least one of the above objectives is achieved by means of an aircraft immobilization system (I, I'; II, III; III') (2000), said system being suitable for being housed in a pit of an aviation runway forming part of an aerodrome or an airport, this system comprising at least one immobilization device (1, 101, 201; 301;401), each immobilization device comprising a frame (2) intended to be fixed to the walls of said pit, a receiving mat (3), forming an endless strip wound around the frame, this mat being intended to receive a landing gear of the aircraft, means (4) for driving this receiving mat relative to the frame, means (5) for braking this receiving mat, control means (8) configured to measure a speed value of the aircraft, before its arrival on the or each immobilization device, to activate the drive means so as to move each receiving mat at a speed greater than or equal to the measured speed, according to the direction of travel of the aircraft, and then to identify the arrival of at least one landing gear on at least one receiving mat; and finally;

[0021] - to deactivate the drive means while activating the braking means when this arrival is identified.

[0022] According to other features of the immobilization system according to the invention, taken individually or in any technically compatible combination: the system further comprises at least one identification element, in particular a contactor (7, 107, 207), capable of identifying the arrival of a landing gear (2300, 2400, 2500) of the aircraft on a respective immobilization device, this arrival identification element being capable of generating said first signal in the direction of the control means. Each receiving conveyor has a length of between 50 and 300 m (meters), in particular between 100 and 250 m, and in particular close to 200 m. The system further comprises at least one main conveyor (3) adapted to receive a main landing gear of said aircraft, this conveyor having a width of between 3.5 and 4.5 m, and in particular close to 4 m.said immobilization system further includes at least one so-called auxiliary mat adapted to receive an auxiliary landing gear of said aircraft, this mat having a width of between 2.5 and 3.5 m, in particular being close to 3 m. said immobilization system further includes means for measuring the speed of the aircraft, before the arrival of each landing gear on a respective receiving mat, these measuring means being capable of generating said second signal in the direction of the control means.

[0023] The invention also relates to the use of the above immobilization system to immobilize an aircraft rolling on an airstrip, particularly at a speed greater than 30 km / h, especially greater than 40 km / h.

[0024] According to other features of this use in accordance with the invention, taken individually or in any technically compatible combination: a) a speed value of the aircraft is measured before its arrival on the immobilization device(s); the drive means are activated so as to move each receiving mat at a speed greater than or equal to the measured speed; the arrival of at least one landing gear on at least one receiving mat is identified; the drive means are deactivated while the braking means are activated upon identification of this arrival; b) the drive means are activated so as to move each receiving mat at a predetermined value before measuring the speed of the aircraft, then if the predetermined value is less than the measured speed value of the aircraft,The drive systems are reactivated to increase the speed of each conveyor belt until it reaches at least the measured value; c) the aircraft is immobilized relative to the receiving conveyor belt(s), in particular by applying the parking brake of that aircraft, immediately after identifying the arrival of at least one landing gear on at least one receiving conveyor belt.

[0025] The invention also relates to an airstrip comprising at least one immobilization system such as above.

[0026] According to other features of this aircraft runway according to the invention, taken individually or in any technically compatible combination: the runway comprises a main taxiway (1100), as well as two runway thresholds (1200, 1300) provided at the two ends of the taxiway, the system(s) being provided in the vicinity of a respective runway threshold; the runway comprises at least one arresting extension located beyond the runway threshold, said immobilization system being placed in the arresting extension, in particular along the median longitudinal axis of the runway; the runway comprises at least one runway threshold without an arresting extension, said immobilization system being located near said runway threshold while being offset from the median longitudinal axis of the runway; the immobilization system(s) comprises:

[0027] • two main immobilizing devices (1, 101), located at substantially the same distance from the runway threshold, each intended to immobilize a respective main landing gear (2300, 2400) of the aircraft; and advantageously

[0028] • an auxiliary immobilizing device (201), offset from the main immobilizing devices along the longitudinal axis of the runway, this auxiliary immobilizing device being advantageously intended to immobilize the auxiliary landing gear (2500) of the aircraft; the runway further includes means for measuring the speed of the aircraft, before the arrival of each landing gear on a respective receiving mat, these measuring means being capable of generating said second signal in the direction of the control means.

[0029] The invention ultimately relates to an airport or aerodrome, comprising at least one runway as described above.

[0030] Description of the figures

[0031] The invention will be described below with reference to the accompanying drawings, given solely by way of non-limiting examples, in which:

[0032] [Fig. 1] is a top view, schematically illustrating an airstrip that can be equipped with an immobilization system according to the invention, as well as the different zones that make up this runway.

[0033] [Fig. 2] is a top view, illustrating on a larger scale the implementation of an immobilization system according to the invention at the end of a track, such as that in Figure 1.

[0034] [Fig. 3] is a side view, illustrating one of the immobilizing components belonging to the immobilizing system of Figure 2. [Fig. 4] is a top view, schematically illustrating the framework of the immobilizing component of Figure 3, as well as its positioning relative to the track.

[0035] [Fig. 5] is a top view, illustrating on a larger scale the inner face of a receiving mat equipping the immobilizing device of figures 3 and 4.

[0036] [Fig. 6] is a schematic view, illustrating the control means of the immobilization system of figures 2 to 5.

[0037] [Fig. 7] is a side view, illustrating a first phase of the implementation of the track of figure 2, equipped with the immobilization system according to the invention.

[0038] [Fig. 8] is a side view, illustrating a second phase of the implementation of the track of figure 2, equipped with the immobilization system according to the invention.

[0039] [Fig. 9] is a side view, illustrating a third phase of the implementation of the track of figure 2, equipped with the immobilization system according to the invention.

[0040] [Fig. 10] is a top view, analogous to figure 1, illustrating the positioning of two immobilization systems according to figures 2 to 8, at opposite ends of an airstrip.

[0041] [Fig. 11] is a top view, similar to figure 2, illustrating a first variant of an embodiment of an immobilization system according to the invention.

[0042] [Fig. 12] is a top view, similar to figure 2, illustrating a second embodiment of an immobilization system according to the invention, more particularly suitable for a light aircraft.

[0043] [Fig. 13] is a top view, similar to figure 1, illustrating the positioning of two immobilization systems according to the invention at opposite ends of an aircraft runway, the arrangement of which represents a first alternative to that of figure 1.

[0044] [Fig. 14] is a top view, similar to figure 1, illustrating the positioning of two immobilization systems according to the invention at opposite ends of an airstrip, the arrangement of which represents a second alternative to that of figure 1.

[0045] The following numerical references will be used in the detailed description given below.

[0046] 1000: track - 1010: pit or excavation - 1020: concrete structure of the track - 1011 and 1012: opposite side walls of 1010 - 1015: rear edge of the pit - 1016: rear end of the pit - 1050: upper surface of the track

[0047] 1100: Main area - 1200, 1300: Runway thresholds - 1250, 1350: Arrest extensions - 1210, 1310: Inner end of thresholds - 1220, 1320: Outer end of thresholds - 2000: Aircraft - 2100: Fuselage - 2200: Wings - 2300 and 2400: Main landing gear - 2500: Auxiliary landing gear. 1: Immobilization system according to the invention. 1, 101: Main immobilization components - 201: Auxiliary immobilization component

[0048] X1, Y1 longitudinal and transverse axes of organ 1

[0049] 2: framework of 1 - 20, 21: beams - 25, 26: rails - 28: rollers

[0050] 3: Receiving mat - 30: Blades of 3 - 31: Connections - 35: Upper surface of the mat

[0051] 4, 104, 204: drive means - 40: motor - 42, 44: shafts - 46, 48: toothed wheels

[0052] 5, 105, 205: braking means - 52, 54: brakes - 56, 58: supports

[0053] 60, 62: guide wheels - 7, 107, 207: contactor - 75: speed measurement module

[0054] 8: control means - 80: central unit - 81, 181, 281: lines between 80 and contactors - 82, 182, 282: lines between 80 and drive means - 83, 183, 283: lines between 80 and braking means - 85: line between 80 and 75 - 87: line between 80 and 88 (lookout controller)

[0055] 301, 401: immobilizing components (figure 11)

[0056] 501: immobilizing device (figure 12)

[0057] 3000: runway - 3300: runway threshold - 3250: stopping extension (Figure 13)

[0058] 4000: runway - 4200, 4300: runway thresholds

[0059] Detailed description

[0060] Figure 1 illustrates an airfield runway of a type known per se, which is designated as a whole by the reference numeral 1000. According to the invention, this runway is part of an aerodrome or airport, namely a structure fixed relative to the ground reference frame. This runway comprises a main flight area 1100 terminated at its two opposite longitudinal ends by runway thresholds 1200 and 1300. These runway thresholds are said to be staggered because each of them terminates, opposite the main area 1100, by a respective stopping extension 1250 and 1350.

[0061] Figure 1 illustrates an aircraft runway, the layout of which corresponds to a first known possibility. Typically, this runway may include a single arresting extension, or it may have no arresting extension at all. Alternatively, instead of one or both arresting extensions, the runway may be equipped with a so-called clear extension. Some of these alternatives are described with reference to Figures 13 and 14, illustrating variations in the implementation of the immobilization systems according to the invention.

[0062] Figure 2 illustrates a preferred embodiment of an immobilization system according to the invention. This system, designated as a whole by reference numeral I, is intended to immobilize an aircraft in an emergency situation. This aircraft 2000, known per se and not part of the invention, essentially comprises a fuselage 2100, two wings 2200, two main landing gears 2300 and 2400, and an auxiliary landing gear 2500.

[0063] As shown in Figure 2, the system I according to the invention advantageously comprises three distinct immobilizing elements. There are two main elements 1 and 101, each specifically designed to cooperate with a respective main landing gear 2300 and 2400, and an auxiliary element 201 specifically designed to cooperate with the auxiliary landing gear 2500. With reference to Figures 3 to 5, the structure of the immobilizing element 1 will now be described in more detail, it being understood that the structure of the other elements 101 and 201 is similar. The mechanical components of the immobilizing elements 101 and 201, which are analogous to those of the immobilizing element 1, are assigned the same reference numbers plus 100 and 200, respectively.

[0064] The immobilizing device 1 is received in a pit or excavation 1010, formed in the concrete structure 1020 of the runway. X1 denotes the longitudinal axis of this device, with reference to the length of the runway, and Y1 denotes the transverse axis. 11 and 12 denote the rear and forward ends of the immobilizing device, respectively, with reference to the aircraft's approach along the runway. In other words, in operation, the aircraft initially reaches the immobilizing device via its rear end 11. 1015 denotes the rear edge of the pit, at the level of the runway surface, and 1016 denotes the rear end of this same pit. Given the semi-circular profile of the immobilizing device in this region, the end 1016 is slightly set back relative to the edge 1015.

[0065] This restraint system comprises, firstly, a frame 2, formed by a plurality of transverse beams 20 and 21, and by a plurality of longitudinal rails 25 and 26. As Figure 3 shows in particular, the various upper beams 20 and lower beams 21 are evenly distributed one behind the other, near the upper and lower surfaces of the pit, respectively. It should be noted that the beams 21 have smaller dimensions than the beams 20, since they are subjected to much lower mechanical stresses. As Figure 4 shows in particular, each beam is mounted, by appropriate means, in the opposite side walls 1011 and 1012 bordering this pit 1010. The rails 25 and 26 are fixed, by appropriate means, to the upper edges of the beams 20 and 21, respectively.The various rails are evenly spaced side by side above the beams. Rails 25 and 26 also support a plurality of cylindrical rollers 28, extending transversely one behind the other. These rollers, which are mounted freely on the rails, are designed to facilitate the movement of the slats of the conveyor belt 3 described below. As can be seen from the above, the beams 20 and rails 25 bear the majority of the load, while the beams 21 and rails 26 serve primarily to guide the conveyor belt 3.

[0066] This receiving mat 3, fitted to the immobilization device 1, defines an endless strip. This mat is formed by a succession of slats 30 joined in pairs by links 31, each of which allows articulation between adjacent slats around a transverse axis, namely parallel to the axis Y1 defined above. In order to ensure the smoothest possible aircraft taxiing, the upper surface 35 of the mat 3 is advantageously flush with the upper surface 1050 of the runway.

[0067] The immobilizing element 1 also includes means 4 for driving the conveyor belt relative to the frame 2. These drive means comprise, firstly, a motor 40, shown schematically, which is advantageously electric. Furthermore, at least one drive shaft is provided, in this case two such shafts 42 and 44 extending transversely and located near opposite ends of the frame. As shown in Figure 3, these shafts are equipped with toothed wheels 46 and 48, the periphery of which has raised features (not shown). These raised features are adapted to mesh with recesses 33, visible in Figure 5, which are formed on the inner face 32 of each blade, i.e., facing inwards towards the endless belt.

[0068] Referring again to Figure 3, the immobilizing device also includes means 5 for braking each drive shaft. Two brakes 52 and 54, of any suitable type, including disc brakes, are provided, each capable of cooperating with the respective toothed wheels 46 and 48. These brakes are equipped with a support 56, 58 mounted, in a manner known per se, on an adjacent beam.

[0069] This immobilizing device 1 also includes various guide wheels, which are mounted freely around a transverse axis. Figure 3 illustrates two of these wheels, 60 and 62, it being understood that additional wheels may be provided. In particular, an end wheel, positioned opposite wheel 60, is advantageously fitted to the immobilizing device. These wheels, which are not driven, are propelled by the movement of the conveyor belt, serving only to guide it.

[0070] Finally, Figure 3 illustrates a contactor 7, of any known type, installed on runway 1000. This contactor is advantageously buried near the edge 1015 of the pit, which provides additional reinforcement for the pit walls, thanks to its metallic nature. As will be seen later, this contactor controls both the braking action and the disconnection of the electric motor's power supply. It also controls the illumination of an indicator light (not shown), for example, blue, located on a lateral edge of the system. Once illuminated, this light authorizes the pilot to engage the parking brake, in order to immobilize the aircraft on the mats before braking and stopping them.

[0071] We will now give, by way of non-limiting example, various relative numerical values, on the one hand, for the main immobilizing devices 1 and 101, and on the other hand, for the auxiliary immobilizing device 201, which values ​​are advantageously suited to the use of the system according to the invention for immobilizing an aircraft in distress: total length L1 of the immobilizing device 1 or 101, namely the distance between its opposite ends 11 and 12, as well as total length L201 of the immobilizing device 201: between 50 and 300 meters, preferably between 100 and 250 meters, in particular close to 200 m; total width (11) of the immobilizing device 1 or 101: between 3.5 and 4.5 m, preferably close to 4 m; total width (1201) of the immobilizing device 201: between 2.5 and 3.5 m, preferably close to 3 m. m

[0072] The person skilled in the art will adapt the load resistance of each immobilizing component, as well as the total power of the electric motor, according to the reception capacities of the different airports or airfields.

[0073] The invention is applicable to various types of aircraft, including commercial aircraft transporting both passengers and cargo, as well as fighter jets. These aircraft, which can be immobilized according to the invention, have a speed such that they cannot change direction without risk of tipping over. This speed is typically greater than 30 km / h, and in particular 40 km / h. The speeds mentioned above are those of the aircraft upon arrival on the receiving mat(s). Advantageously, the transverse distance (E201) between the opposite edges of each immobilizing device 1 and 101, and the immobilizing device 201, is greater than 75 cm. Typically, this distance is between 75 and 200 cm, preferably between 100 and 150 cm.

[0074] The distance (Ds), along the longitudinal direction, between the runway threshold and the end opposite each immobilization device 1, 101, will be chosen according to the topography of the airport or aerodrome. It is understood that the shorter the stopping extension 1250, the smaller this distance (Ds) will be.

[0075] Figure 6 illustrates the control means equipping the immobilization system I according to the invention, which are collectively designated by reference numeral 8. In this figure 6, the three immobilization elements 1, 101, and 201, forming this immobilization system, are schematically illustrated. These control means comprise a central unit 80, initially connected to the contactors 7, 107, and 207 by respective lines 81, 181, and 281. The central unit is also capable of controlling the drive means 4, 104, and 204, by respective lines 82, 182, and 282, as well as the braking means 5, 105, and 205, by respective lines 83, 183, and 283.

[0076] The immobilization system according to the invention is further advantageously equipped with a module 75, which measures the aircraft's speed. As shown in Figure 3, this measuring module is, for example, positioned behind the main components 1 and 101. A different positioning of the measuring module can be chosen to ensure optimal speed measurement. The measured values ​​are transferred from module 75 to the central unit 8 via an additional line 85. Finally, another line 87 connects this central unit to the lookout controller, shown schematically and designated by reference numeral 88.

[0077] An example of the implementation of the immobilization system I, described above, will now be explained with reference in particular to figures 7 to 9.

[0078] It is assumed that an aircraft 2000, operating over the main zone 1100, is experiencing a malfunction that could endanger it. It should be noted that, as will be detailed below, the invention advantageously allows an aircraft experiencing a malfunction to be immobilized not only during landing but also during takeoff. The control means 8 can initially be triggered by the air traffic controller 88, possibly following a request from the captain. This triggering can also be automatic, particularly when the module 75 detects an aircraft speed exceeding a predetermined threshold.

[0079] The value of the speed V2000 of the aircraft 2000, detected by the module, is transmitted to the central unit 8. The latter activates the drive means 4,104 and 204, so that each conveyor belt 3,103 and 203 is driven at a speed V3, V103, V203 greater than or equal to the measured speed V2000. In practice, equal speeds will be chosen.

[0080] According to an advantageous embodiment of the invention, the conveyor belts can be set in motion before the aircraft's speed is measured. In this scenario, an alert is issued at an early stage, as soon as a malfunction is detected, particularly by the pilot in command. The central unit then sets each belt in motion at a predetermined speed, denoted V0. It then compares this predetermined speed with the measured speed, denoted Vm, and subsequently acts on the drive system to modify the belts' speed as needed. In particular, if the measured speed is higher than the predetermined speed, the central unit accelerates each belt to bring it to a speed equal to the measured speed. Conversely, if the measured speed is lower than the predetermined speed, the belt can be slowed down as necessary.

[0081] According to an essential feature of the invention, the conveyor belts are driven so as to move in the direction of the aircraft's forward movement, namely from left to right in Figure 7. The activation of drive shafts 42 and 44 is shown in Figure 7, indicated by arrows F42 and F44. The displacement F2000 of the aircraft relative to the runway surface is also shown, as well as the displacements F1 and F201 of the immobilizing devices 1 and 201. The displacement of device 101, which is hidden in Figure 7, is identical to the displacement F1. The braking means 5 are deactivated, and are therefore represented by dashed lines in Figure 7.

[0082] When each landing gear 2300, 2400, and 2500 passes in front of contactors 7, 107, and 207 respectively, as illustrated in Figure 8, the corresponding information is relayed to the control unit via lines 81, 181, and 281. Note that contactor 107, shown schematically in Figure 6, is not shown in Figure 8 because it is located behind contactor 7. This control unit then deactivates the propulsion system, which is represented by the dashed lines on shafts 42 and 44, while simultaneously activating the braking system, which is now shown with solid lines. The control unit performs the above operations first for auxiliary component 201, and then for the main components 1 and 101, since the latter are offset along the longitudinal axis.

[0083] At approximately the same time as each landing gear passes each contactor, as described above, the aircraft's wheels make contact with the receiving mats 3, 103, and 203. It should be noted that, at this instant, the aircraft's linear speed is less than or equal to that of the mats. Indeed, compared to its passage past the contactors 7, 107, and 207, the aircraft has undergone a slight deceleration, primarily due to friction. Upon wheel contact, their rotation stops almost immediately, as indicated by the crossed arrows F'2300 and F'2500 in Figure 8.

[0084] The pilot can then immobilize the aircraft relative to the various mats by activating the parking brake. The aircraft's speed, in the frame of reference of the immobilization system according to the invention, is zero. However, the various reception mats, as well as the aircraft they support, are still mobile relative to the runway frame of reference, as indicated by arrows F1 and F2000 placed one below the other. It should be noted that the parking brake, activated according to the above operation, is separate from the main braking system. It should also be noted that, once on the reception mats, the aircraft is not braked by this main system, but is only held in position relative to the mat by the parking brake.

[0085] Thanks to the braking system, the goal is to slow down and then stop, within the runway's frame of reference, the mats and, consequently, the aircraft immobilized on them. Figure 9 illustrates both the aircraft and the landing mats once immobilized, as indicated by the crossed arrows F'1 and F'2000. It should be noted that this aircraft has moved along each immobilization device, relative to its position in Figure 8, while remaining on the surface of the various landing mats.

[0086] According to a particularly advantageous feature of the invention, there can be a latency period between, on the one hand, the moment when the aircraft's wheels make contact with the landing mats and, on the other hand, the moment when the control unit deactivates the propulsion system while activating the braking system. This latency period, which is typically close to one second, prevents any slippage of the aircraft's wheels on the aforementioned mats. Based on the configuration shown in Figure 9, two possibilities can be considered. The aircraft failure may first be minor, namely that the aircraft had to be immobilized by the system according to the invention due to an excessive approach speed, typically linked to a malfunction of its high-lift flaps. However, this aircraft is still capable of taxiing under its own power.In this way, the pilot can move the aircraft at low speed, without the intervention of ground crew, until it comes to a complete stop at the terminal. The overall downtime is therefore particularly short, without disrupting air traffic.

[0087] In the event of a major failure, where the aircraft cannot continue taxiing under its own power after being immobilized by the system according to the invention, ground crew must intervene to free the aircraft. The total immobilization time will then correspond to the time required to tow the aircraft to free it and thus clear the runway. This duration remains relatively short, on the order of ten minutes. It should be noted that this operation can be carried out using an aerodrome tractor, without requiring the use of a high-capacity crane as in the prior art using the arresting beds mentioned above.

[0088] As shown in Figure 10, runway 1000 includes, in addition to the immobilization system I described above, a supplementary immobilization system I' located at the other end of the runway. The various mechanical components of system I' are positioned symmetrically with respect to those of system I, on either side of a median axis Y1000 of the runway. Typically, an aircraft can take off and / or land from either end of a runway, depending in particular on weather conditions. Therefore, the arrangement shown in Figure 10 allows for the immobilization of an aircraft experiencing potential difficulties, regardless of its direction of travel.

[0089] We will now describe different variants and alternatives, in relation to the main embodiment shown in figures 1 to 10.

[0090] In this main embodiment, each immobilization system comprises three immobilization elements, each of which is capable of cooperating with a respective landing gear of the aircraft. The variant in Figure 11 provides only two immobilization elements, 301 and 401, cooperating with the main landing gear. In other words, the immobilization system II according to Figure 11 lacks an auxiliary immobilization element, such as that 201 of the main embodiment. This variant of Figure 11 is economically advantageous without compromising safety. It is particularly well-suited to relatively light airliners.

[0091] Figure 12 describes a second variant, in which the immobilization system III comprises a single immobilization element 501. This element is capable of cooperating with all three landing gears, it being understood that an immobilization system III', shown in dashed lines, can be provided, cooperating only with the main landing gear. This variant of Figure 12 is more particularly suited to fighter aircraft, here designated by the reference 2500, whose width is typically less than 4 m and whose weight is typically less than 50 tonnes.

[0092] In the main embodiment, as well as in the variants of figures 11 and 12, the opposite ends of track 1000 are equipped with respective stopping extensions.

[0093] According to a first alternative, illustrated in Figure 13, the invention also finds its application to a runway 3000 equipped with a single stopping extension 3250. In this case, the latter is associated with a first immobilization system I, positioned similarly to that described above. However, unlike Figures 11 and 12, the other immobilization system I' is located near the threshold 3300, which lacks an extension, while being offset from the runway's median axis X3000.

[0094] Thus, an aircraft can be immobilized by system I' when it is taxiing from right to left, as shown in Figure 13. Furthermore, when another aircraft lands on the runway from left to right, it does not exert any mechanical force on this immobilization system I'. This prevents any damage to the system, since the load created by an aircraft landing is much greater than that of the same aircraft taxiing on the runway.

[0095] According to a second alternative, illustrated in Figure 14, the invention also finds its application on a runway 4000 without any stopping extension. In this case, the two immobilization systems I and I' are provided in the vicinity of the runway thresholds 4200 and 4300, being laterally offset with respect to the median axis X4000.

[0096] As can be seen from the above description, the invention offers numerous advantages over the prior art. The system according to the invention provides for immobilizing an aircraft in distress while taxiing on a runway, without exerting significant stress on the aircraft. Essentially, this immobilization is achieved by transferring the aircraft's energy upon its arrival on the receiving mats, which are fitted to the various immobilization devices. Under these conditions, an aircraft immobilized according to the invention remains in perfect flying condition.

[0097] Compared to prior art using an arresting bed, the invention eliminates the need for any subsequent operations to check the structural integrity of the aircraft. For example, in the event of a failure of its high-lift flaps, the aircraft will be able to take off again the same day after being immobilized thanks to the system of the invention.

[0098] Furthermore, the invention eliminates any technical downtime of the runway, since the implementation of the immobilization system does not alter its mechanical structure. Consequently, the operating cost of the system, according to the invention, remains negligible. Aircraft diversions, observed in the prior art using arresting beds, are also eliminated.

[0099] According to a particularly advantageous feature, the invention also finds application in immobilizing aircraft during their takeoff phase. Indeed, since the speed of the landing mats is adjustable according to the aircraft's speed, the system according to the invention can be adapted to immobilize an aircraft experiencing difficulties during takeoff.

[0100] We will now highlight the differences between the present invention and the various prior immobilization systems presented in the preamble to this description. First, it should be noted that, according to the invention, the immobilization devices are set in motion in the same direction as the aircraft's forward movement, unlike in prior documents. The technical effects related to this difference will be explained below.

[0101] It should first be recalled that, to immobilize an aircraft, its kinetic energy must be absorbed. The invention is not based on a progressive reduction of the aircraft's speed, but on a system allowing for the instantaneous dissipation of this kinetic energy. In this respect, the kinetic energy is transferred from the aircraft to the mats as soon as the landing gear makes contact with these mats. At this moment, advantageously by activating the parking brake, it is no longer the aircraft that possesses this kinetic energy, but the mats themselves. Conversely, in the prior art, in particular CN102198864, the immobilizing devices are set in motion in the opposite direction to the aircraft's forward movement. This is theoretically logical, since opposing forward movement seems, at first glance, intuitive for ensuring immobilization.However, in this solution, the aircraft will have to absorb this kinetic energy by its own means in order to come to a stop.

[0102] Under these conditions, the present invention finds its application in emergency situations where the aircraft is no longer able to slow down normally. The invention does not seek to prolong or improve a standard maneuver, but rather to immediately neutralize an aircraft in distress in order to dissipate its kinetic energy and preserve the lives of passengers and crew. The invention therefore falls under the category of absolute safety in an emergency.

[0103] In contrast, prior art is used solely to improve passenger comfort on an aircraft that is mechanically sound. Known solutions thus optimize the landing phase by slowing the aircraft down, which is entirely different from the object of the present invention.

[0104] In summary, the prior art, which relates to easier landing, falls under the category of operational assistance in controlled flight. In contrast, the immobilization system according to the invention constitutes a last resort safety system designed to preserve the lives of passengers and crew when all normal procedures have become ineffective.

[0105] The invention is not limited to the examples described and shown.

[0106] Runway thresholds can be made from any suitable material. Concrete is a preferred material, but earth or other materials are also options.

[0107] Finally, the immobilization system, according to the invention, can be provided at other locations on the runway than those described above. For example, such an immobilization system can be installed in a runway bypass, also known as a "Rapid Exit".

Claims

DEMANDS 1. Aircraft immobilization system (I, I'; II, III; III') (2000), said system being suitable for housing in a pit of an aviation runway forming part of an aerodrome or an airport, said system comprising at least one immobilization device (1, 101, 201; 301;401), each immobilization device comprising: a frame (2) intended to be fixed to the walls of said pit, a receiving mat (3), forming an endless strip wound around the frame, this mat being intended to receive a landing gear of the aircraft, means (4) for driving this receiving mat relative to the frame, means (5) for braking this receiving mat, control means (8) configured to measure a speed value of the aircraft, before its arrival on the or each immobilization device, to activate the drive means so as to move each receiving mat at a speed greater than or equal to the measured speed, according to the direction of travel of the aircraft, and then to identify the arrival of at least one landing gear on at least one receiving mat; and finally; - to deactivate the drive means while activating the braking means when this arrival is identified.

2. Immobilization system according to claim 1, further comprising at least one identification element, in particular a contactor (7, 107, 207), capable of identifying the arrival of a landing gear (2300, 2400, 2500) of the aircraft on a respective immobilization device, this arrival identification element being capable of generating said first signal in the direction of the control means.

3. Immobilization system according to any one of the preceding claims, wherein each receiving mat has a length between 50 and 300 m (meters), in particular between 100 and 250 m, in particular being close to 200 m.

4. Immobilization system according to any one of the preceding claims, comprising at least one main mat (3) adapted to receive a main landing gear of said aircraft, this mat having a width between 3.5 and 4.5 m, in particular being close to 4 m.

5. Immobilization system according to any one of the preceding claims, comprising at least one so-called auxiliary mat adapted to receive an auxiliary landing gear of said aircraft, this mat having a width between 2.5 and 3.5 m, in particular being close to 3 m.

6. Immobilization system according to any one of the preceding claims, comprising at least further means for measuring the speed of the aircraft, before the arrival of each landing gear on a respective receiving mat, these measuring means being capable of generating said second signal in the direction of the control means.

7. Use of a system according to any one of the preceding claims, to immobilize an aircraft rolling on an airstrip, in particular at a speed greater than 30 km / h, in particular greater than 40 km / h.

8. Use according to the preceding claim, wherein a speed value of the aircraft is measured, before its arrival on the or each immobilizing device, the drive means are activated so as to move each receiving mat at a speed greater than or equal to the measured speed, according to the direction of forward movement of the aircraft, the arrival of at least one landing gear on at least one receiving mat is identified, the drive means are deactivated while the braking means are activated upon identification of this arrival.

9. Use according to the preceding claim, wherein the drive means are activated so as to move each receiving mat to a predetermined value, before measuring the speed of the aircraft, then if the predetermined value is less than the measured speed value of the aircraft, the drive means are activated again so as to increase the speed of each mat until it reaches at least the measured value.

10. Use according to any one of claims 7 to 9, wherein the aircraft is immobilized with respect to the landing mat or mats, in particular by actuating the parking brake of the aircraft, immediately after identifying the arrival of at least one landing gear on at least one landing mat.

11. Aircraft runway (1000), belonging to an airport or aerodrome, this runway comprising at least one immobilization system according to one of claims 1 to 6.

12. Runway according to claim 11, comprising a main taxiing area (1100), as well as two runway thresholds (1200, 1300) provided at the two ends of the taxiing area, the system or each system being provided in the vicinity of a respective runway threshold.

13. Runway according to claim 11, comprising at least one stopping extension situated beyond the runway threshold, said immobilization system being placed in the stopping extension, in particular along the median longitudinal axis of the runway.

14. Runway according to claim 11, comprising at least one runway threshold without a stopping extension, said immobilization system being located near said runway threshold while being offset from the median longitudinal axis of the runway.

15. Runway according to any one of claims 11 to 14, wherein the or each immobilization system comprises two main immobilization devices (1,101), located substantially at the same distance from the runway threshold, each intended to immobilize a respective main landing gear (2300, 2400) of the aircraft; and advantageously an auxiliary immobilization device (201), offset from the main immobilization devices along the longitudinal axis of the runway, this auxiliary immobilization device being advantageously intended to immobilize the auxiliary landing gear (2500) of the aircraft.

16. Runway according to any one of claims 11 to 15, further comprising means for measuring the speed of the aircraft, before the arrival of each landing gear on a respective receiving mat, these measuring means being capable of generating said second signal in the direction of the control means.

17. Airport or aerodrome comprising at least one runway according to one of the claims 11 to 16.

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