Aircraft fuel tank inerting system

Abstract

The present disclosure relates to an aircraft fuel tank inerting system, which may include at least one fuel tank, at least one vent tank, an inert air assembly, at least one fluid valve connected to the at least one fuel tank, the at least one vent tank and the inert air assembly, and / or an electronic control unit. The electronic control unit may control the at least one fluid valve to provide inert air from the inert air assembly to the at least one fuel tank and / or to the at least one vent tank. The electronic control unit may control the at least one fluid valve to provide inert air from the inert air assembly to the fuel tank during a climb phase of flight, and control the at least one fluid valve to provide inert air from the inert air assembly to the at least one vent tank during a descent phase of the flight.

Description

Technical Field

[0001] The present disclosure relates generally to fuel systems, including systems and methods for inerting fuel tanks that may be used in aerospace applications. Background Art

[0002] The background description is listed below for the purpose of providing context only. Therefore, no aspect of the background description is admitted, either explicitly or implicitly, as prior art to the instant disclosure to the extent that it is not otherwise prior art.

[0003] Some inerting systems may not operate efficiently and / or may be relatively cumbersome.

[0004] It would be desirable to have a solution / option that minimizes or eliminates one or more of the problems or disadvantages of inerting systems.The above discussion is intended only to illustrate examples of the art and should not be considered a denial of scope. Summary of the invention

[0005] In an embodiment, an aircraft fuel tank inerting system may include a fuel tank, a vent tank, an inert air assembly, fluid valves connected to the fuel tank, the vent tank, and the inert air assembly, and / or an electronic control unit. The electronic control unit may be configured to control the fluid valves to provide inert air from the inert air assembly to the fuel tank and / or the vent tank. The electronic control unit may be configured to control the fluid valves to provide inert air from an inert air source to the fuel tank during a climb phase of flight, and to control the fluid valves to provide inert air from an inert air source to the vent tank during a descent phase of flight.

[0006] The above and other aspects, features, details, utilities and / or advantages of embodiments of the present disclosure will become apparent by reading the following description and by viewing the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 A schematic diagram generally illustrates an embodiment of an aircraft fuel tank inerting system in accordance with the teachings of the present disclosure.

[0008] Figure 2 A schematic diagram generally illustrates an embodiment of an aircraft fuel tank inerting system in accordance with the teachings of the present disclosure.

[0009] Figure 3 A schematic diagram generally illustrates an embodiment of an aircraft fuel tank inerting system in accordance with the teachings of the present disclosure.

[0010] Figure 4A and Figure 4B A schematic diagram generally illustrates components of a vent tank of an embodiment of an aircraft fuel tank inerting system in accordance with the teachings of the present disclosure.

[0011] FIG. 5A to FIG. 5C Schematic diagrams generally illustrate fluid valves in different positions of an embodiment of an aircraft fuel tank inerting system in accordance with the teachings of the present disclosure. DETAILED DESCRIPTION

[0012] Reference will now be made in more detail to embodiments of the present disclosure, examples of which are described herein and shown in the accompanying drawings. Although the present disclosure will be described in conjunction with the embodiments and / or examples, it should be understood that they are not intended to limit the present disclosure to these embodiments and / or examples. On the contrary, the present disclosure is intended to cover alternatives, modifications and equivalents.

[0013] In an embodiment, such as Figure 1 As generally shown in FIG. 1 , an aircraft fuel tank inerting system 10 may include an inert air assembly 12, one or more main fuel tanks 14, 16, 18 (e.g., a left wing tank 14, a right wing tank 16, and / or a center tank 18), one or more vent tanks 20, 22 (e.g., a left wing vent tank 20 and / or a right wing vent tank 22), one or more fluid valves 24, 26, 28 (e.g., a first fluid valve 24, a second fluid valve 26, and / or a third fluid valve 28), and / or an electronic control unit (ECU) 30. The aircraft fuel tank inerting system 10 may be configured to maintain a certain maximum oxygen (O2) level in the air in the fuel tanks 14, 16, 18 in order to mitigate or eliminate the risk of fire or explosion.

[0014] According to the embodiment, such as Figure 1 and Figure 2As generally shown in FIG. 1 , the inert air assembly 12 may be configured to receive a fluid, such as exhaust air 32 from an aircraft engine 102, and provide an inert air 34. The inert air 34 may include, for example and without limitation, nitrogen enriched air (NEA). The exhaust air 32 from the engine 102 may flow to an exhaust air isolation valve 36 of the inert air assembly 12. The exhaust air 32 may then flow to a pressure switch 38 (e.g., a differential pressure switch) and a filter / ozone converter 40, which may be connected in parallel. A pressure sensor 42 and / or a temperature sensor 44 may be connected between (i) the isolation valve 36 and (ii) the pressure switch 38 and the filter / ozone converter 40. Water may be removed from the exhaust air 32 and discharged. The exhaust air 32 may flow to one or more air separation modules (ASMs) 46. One or more ASMs 46 may be configured to reduce the amount of oxygen in the exhaust air 32 and / or increase the amount of nitrogen (or other inert gas) in the exhaust air 32, such as to provide inert air 34. One or more ASMs 46 may be configured to provide inert air 34, which may contain less than 20% oxygen, less than 15% oxygen, less than 10% oxygen, and / or less than 5% oxygen, or other levels of oxygen. Oxygen enriched air (OEA) may be a byproduct of the ASMs 46 and may be exhausted, such as via a ram air outlet 48. The inert air 34 may be provided to the boxes 14, 16, 18, such as via a flow control valve 50, a high flow orifice 52, and / or a low flow orifice 54. A pressure sensor 42 and / or an oxygen sensor 56 may be connected at or near the outlet of one or more ASMs 46. The pressure sensor 42 and / or the bleed / relief valve 58 may be connected between one or more of the orifices 52 , 54 and a flame arrestor / check valve 60 that may be disposed at an inert air outlet 62 of the inert air assembly 12 .

[0015] In an embodiment, the ECU 30 may be configured to control one or more portions of the inert air assembly 12, such as and without limitation, an exhaust air isolation valve 36, a differential pressure switch 38, a filter / ozone converter 40, one or more ASMs 46, and / or a flow control valve 50. The inert air assembly 12 may be, for example and without limitation, at least partially disposed in a wing 104, 106 of the aircraft 100, such as in a fairing of the wing 104, 106.

[0016] According to the embodiment, such as Figure 3As generally shown in FIG. 1 , the aircraft 100 may include one or more main fuel tanks 14, 16, 18, such as a left wing tank 14, a right wing tank 16, and / or a center tank 18. Additionally or alternatively, the aircraft 100 may include one or more vent tanks 20, 22, such as a left vent tank 20 and a right vent tank 22. The vent tanks 20, 22 may be configured to receive fuel from the main fuel tanks 14, 16, 18, such as in the event that high temperatures cause expansion of fuel in the main tanks 14, 16, 18, fuel sloshing due to maneuvers, and / or refueling spillage. The aircraft fuel inerting system 12 may be configured to provide inert air 34 to some or all of the tanks 14, 16, 18.

[0017] In an embodiment, such as Figure 3 , Figure 4A and Figure 4B As generally shown in FIG. 1 , the vent tanks 20, 22 may include one or more vent tank components 64, 66. For example and without limitation, the vent tanks 20, 22 may include one or more climb and descent valves 68, pressure relief valves 70 (e.g., for refueling and emergency descent), flame arresters 72, and / or one or more bleed / decompression valves 74. The vent tank components 64, 66 may be in fluid communication with the environment (e.g., ambient / outside air) and may be configured to exhaust air from the tanks 14, 16, 18 if the pressure in the tanks 14, 16, 18 is above a threshold value and / or may be configured to receive outside air if the pressure (or pressure differential) in the tanks 14, 16, 18 is below a threshold value. The vent tanks 20, 22 may be disposed at or near the outer ends of the wings 104, 106 of the aircraft 100.

[0018] According to the embodiment, such as Figure 1 , Figure 3 and FIG. 5A to FIG. 5C As generally shown in FIG. 1 , an aircraft fuel tank inerting system 10 may include one or more fluid valves 24, 26, 28. For example and not limitation, an aircraft fuel tank inerting system 12 may include a fluid valve 24, 26 for each vented tank 20, 22, although the fluid valve 28 may be used with more than one vented tank 20, 22. The fluid valves 24, 26, 28 may be configured to control the flow of inert air 34 (from the inert air assembly 12) into the tanks 14, 16, 18. An inlet 76 of the fluid valve 24, 26, 28 may be in fluid communication with an outlet 62 of the inert air assembly 12. A first outlet 78 of the fluid valve 24, 26, 28 may be in fluid communication with the main / wing tank 14, 16, 18. A second outlet 80 of the fluid valve 24, 26, 28 may be in fluid communication with the vented tank 20, 22. In a first / closed position, as shown in FIG. 1 , the inert air 34 may flow into the tank 14, 16, 18. Figure 5AAs generally shown in FIG. 1 , the fluid valves 24, 26, 28 may block fluid communication between the inlet 76 and the first and second outlets 78, 80 (e.g., the inert air 34 may not be provided to any of the boxes 14, 16, 18, 29, 22), such as to enable a BIT (built-in self-test) to be performed to check for potential faults in the fluid distribution system. In the second / open position, as shown Figure 5B As generally shown in FIG. 1 , the fluid valves 24, 26, 28 may provide fluid communication between the inlet 76 and the first outlet 28 (eg, to provide inert air 34 to the main / wing box 14, 16, 18). Figure 5C As generally shown in FIG. 1 , the fluid valves 24, 26, 28 may provide fluid communication between the inlet 76 and the second outlet 80 (e.g., to provide the inert air 34 to the vent oil tanks 20, 22). The fluid valves 24, 26, 28 may be disposed in the main tank 14, 16, 18, partially disposed in the vent oil tanks 20, 22, or completely disposed in the vent oil tanks 20, 22.

[0019] In an embodiment, the ECU 30 may be configured to control the operation of one or more fluid valves 24, 26, 28, such as between a closed position, an open position, and a bypass position. If the air in the fuel tanks 14, 16, 18 has a sufficiently low oxygen concentration and / or if the aircraft 100 is on the ground, the ECU 30 may operate the fluid valves 24, 26, 28 (e.g., the first fluid valve 24, the second fluid valve 26, and / or the third fluid valve 28) in a closed position. The ECU 30 may be connected to a sensor 82 (e.g., a weight on wheel sensor) that may indicate whether the aircraft 100 to which the ECU 30 is connected is on the ground. If the ECU 30 determines that the aircraft 100 is on the ground, the ECU 30 may operate (or maintain) the fluid valves 24, 26, 28 in a closed position. Additionally or alternatively, if the tank 14, 16, 18 reaches a sufficient inert margin (e.g., an oxygen concentration of about 14% or less), the ECU 30 may operate the fluid valve in a closed position during the cruise phase of flight. The ECU 30 may operate the fluid valve in a closed position to perform a test, such as a built-in self-test (BIT) function, which may evaluate the operation of one or more other valves 14, 16, 18 in the fuel tank inerting system 10. The ECU 30 may be configured to independently control the first fluid valve 24, the second fluid valve 26, and the third fluid valve 28. The ECU 30 may be connected to one or more sensors 84 that may be configured to obtain information about the tank 14, 16, 18, such as and without limitation, an oxygen sensor that may provide information about the oxygen concentration in the air in the tank 14, 16, 18.

[0020] According to an embodiment, the ECU 30 may operate the fluid valves 24, 26, 28 in the open / second position during the climb phase of flight and / or during the cruise phase of flight (e.g., if the tanks have not yet reached a sufficient inert margin). In the open position, the fluid valves may provide inert air 34 from the inert air assembly 12 to the tanks 14, 16, 18 via one or more first fluid conduits 86. The inert air 34 may flow into the first fluid conduits 86 and may exit the first fluid conduits 86 at one or more locations along the first fluid conduits 86 into the tanks 14, 16, 18. The inert air 34 may mix with tank air, which may have a higher oxygen concentration than the inert air 34, to reduce the oxygen concentration of the tank air, such as to a level below a threshold value (e.g., 12% at 20,000 feet and 14% between 20,000 feet and a cruise ceiling of approximately 43,000 feet).

[0021] In an embodiment, the ECU 30 may be configured to operate the fluid valves 24, 26, 28 in the bypass / third position. In the bypass position, the fluid valves 24, 26, 28 may provide inert air 34 from the inert air assembly 12 to the vent tanks 20, 22. The ECU 30 may operate the fluid valves 24, 26, 28 in the bypass position during the descent phase of flight and / or in situations where the pressure in the tanks 14, 16, 18 is significantly lower than the ambient air pressure. In this case, outside / ambient air may flow into the vent tanks 20, 22 and then into the main tanks 14, 16, 18 to equalize the pressure in these main tanks at least to some extent. The ambient air entering the vent tanks 20, 22 may contain a relatively high concentration of oxygen, such as about 20%-22%. The fluid valves 24, 26, 28 may provide the inert air 34 to the vent tanks 20, 22, and the inert air 34 may be mixed with the ambient air in the vent tanks 20, 22 (e.g., the vent tanks 20, 22 may act as a mixing chamber). The resulting mixed air may include a reduced oxygen concentration. For example and without limitation, the mixed air may include an oxygen concentration of approximately 14%-16%. The mixed air may flow from the vent tanks 20, 22 into a second fluid conduit 88, which may be connected to one or more main tanks 14, 16, 18. The mixed air may flow through the second fluid conduit 88, and may exit the second fluid conduit 88 at one or more locations along the second fluid conduit 88 into one or more main tanks 14, 16, 18. The mixed air may continue to mix in the second fluid conduit 88.

[0022] In an embodiment, the first fluid valve 24 may be connected to the left wing box 14 and the left vent tank 20, the second fluid valve 26 may be connected to the right wing box 16 and the right vent tank 22, and / or the third fluid valve 28 may be connected to the center box 18 and one or both of the vent tanks 20, 22. The first fluid valve 24 and the second fluid valve 26 may include substantially the same configuration (e.g., having a closed position, an open position, and a bypass position). The third fluid valve 28 may include a different configuration than the first fluid valve 24 and the second fluid valve 26. For example and without limitation, the third fluid valve 28 may include a closed position and an open position, and may not include a bypass position. The ECU 30 may operate the third fluid valve 28 in an open position to reduce the oxygen concentration in the center box 18.

[0023] According to an embodiment, the second fluid conduit 88 may be connected to the left vent oil tank 20 and the right vent oil tank 22. One or more second fluid conduits 88 connected to the first vent oil tank 20 may provide fluid communication from the first vent oil tank 20 to the left wing box 14 and / or to the center box 18. One or more second fluid conduits 88 connected to the second vent oil tank 22 may provide fluid communication from the second vent oil tank 22 to the right wing box 16 and / or to the center box 18. For example and without limitation, the ECU 30 may operate the first fluid valve 24 and the second fluid valve 26 in the bypass position so that mixed air is provided from the left vent oil tank 20 and the right vent oil tank 22 to the main boxes 14, 16, 18 via the second fluid conduit 88.

[0024] According to an embodiment, a method of inerting an aircraft fuel tank may include providing an aircraft 100 having an aircraft fuel tank inerting system 10, at least one fuel tank 14, 16, 18, and / or at least one vent tank 20, 22. The aircraft fuel tank inerting system 10 may include at least one fluid valve 24, 26, 28 and an inert air assembly 12. The method may include operating one or more fluid valves 24, 26, 28 in an open position during a climb phase of flight to provide inert air 34 from the inert air assembly 12 to one or more fuel tanks 14, 16, 18. The method may include operating one or more fluid valves 24, 26, 28 in a closed position during a cruise phase of flight if the fuel tanks 14, 16, 18 have reached an inert margin above a threshold. The method may include operating one or more fluid valves 24, 26, 28 in a bypass position during a descent phase of flight to provide inert air 34 to the vent tanks 20, 22. The method may include mixing the inert air 34 from the inert air assembly 12 with the ambient air in the vent tanks 20, 22 to form a mixed air. The mixed air may continue to mix in the second fluid conduit 88, which may be connected to the vent tanks 20, 22 and the fuel tanks 14, 16, 18. The method may include providing the mixed air to the fuel tanks 14, 16, 18. The method may include operating the (first) fluid valve 24 and the second fluid valve 26 in a bypass position to provide the mixed air from the (first) vent tank 20 to the (left wing) fuel tank 14, from the second vent tank 22 to the second (right wing) fuel tank 16 and / or from both the (first) vent tank 20 and the second vent tank 22 to the third (center) fuel tank 18 via the second fluid conduit 88. The method may include operating one or more fluid valves 24, 26, 28 in a closed position if the aircraft 100 is on the ground. One or more portions of the method may be implemented / performed via the ECU 30.

[0025] According to some designs, outside / ambient air may be provided directly to the main tank from the vent tank, and inert air may be provided separately to the main tank. Ambient air may be provided directly to the main tank at one or more discrete locations. Because ambient air may contain high levels of oxygen, the flow of ambient air into the tank may create areas / regions of higher concentration oxygen in the main tank that may be referred to as "hot spots." To limit the impact of such an arrangement, the air in the main tank may be maintained at an even lower oxygen level to compensate for the ambient air, which may involve providing additional inert air to the main tank. Providing additional inert air to the main tank may involve increasing the capacity and / or duty cycle of the inert air assembly (e.g., increasing the number of ASMs).

[0026] In contrast, depending on the embodiment of the aircraft fuel tank inerting system 10, ambient air may not be provided directly to the main tanks 14, 16, 18. Instead, ambient air may be premixed with the inert air 34 so that the air entering the main tanks 14, 16, 18 (e.g., mixed air) has a reduced oxygen concentration, which may limit and / or prevent the generation of hot spots. For such embodiments, the maximum capacity of the inert air assembly may be reduced, which may reduce the weight of the inert air assembly (e.g., the inert air assembly may include fewer ASMs, which may each weigh approximately 30 pounds). Additionally or alternatively, the duty cycle of the inert air assembly 12 may be reduced due to the lower demand for inert air, which may increase the life cycle of the inert air assembly 12.

[0027] In an embodiment, ECU 30 may include an electronic controller and / or include an electronic processor, such as a programmable microprocessor and / or a microcontroller. In an embodiment, ECU 30 may include, for example, an application specific integrated circuit (ASIC). ECU 30 may include a central processing unit (CPU), a memory (e.g., a non-transient computer readable storage medium) and / or an input / output (I / O) interface. ECU 30 may be configured to perform various functions, including those described in more detail herein, using appropriate programming instructions and / or codes embodied in software, hardware and / or other media. In an embodiment, ECU 30 may include multiple controllers. In an embodiment, ECU may be connected to a display, such as a touch screen display.

[0028] Various embodiments of various devices, systems and / or methods are described herein. Numerous specific details are set forth in order to provide a comprehensive understanding of the overall structure, function, manufacture and use of the embodiments described in the specification and shown in the drawings. However, it should be understood by those skilled in the art that the embodiments can be implemented without such specific details. In other examples, well-known operations, parts and elements are not described in detail so as not to obscure the embodiments described in this specification. It will be understood by those of ordinary skill in the art that the embodiments described and shown herein are non-limiting examples, and therefore it should be understood that the specific structural and functional details disclosed herein may be representative and do not necessarily limit the scope of the embodiments.

[0029] References throughout the specification to "various embodiments," "according to an embodiment," "in an embodiment," or "an embodiment," etc., mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Therefore, the phrases "in various embodiments," "according to an embodiment," "in an embodiment," or "an embodiment," etc., appearing in places throughout the specification do not all refer to the same embodiment. In addition, particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Therefore, specific features, structures, or characteristics shown or described in connection with one embodiment / example may be combined in whole or in part with features, structures, functions, and / or characteristics of one or more other embodiments / examples, but in a non-limiting manner, provided that such combination is not illogical or non-functional. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the scope of the present disclosure.

[0030] It should be understood that reference to a single element is not limiting and may include one or more such elements. Any directional references (e.g., plus, minus, upper, lower, upward, downward, left, right, leftward, rightward, top, bottom, above, below, vertical, horizontal, clockwise, and counterclockwise) are used only for identification purposes to help the reader understand the present disclosure and are not limiting, especially with respect to the position, orientation, or use of the embodiments.

[0031] The reference of the joint (for example, attachment, coupling, connection, etc.) should be understood as broad, and may include the intermediate member between the connection portion of the element and the relative motion between the elements. Therefore, the reference of the joint does not mean that two elements are directly connected / coupled and fixed to each other. The use of "for example" in this specification should be understood as broad, and is used to provide a non-limiting example of the embodiment of the present disclosure, and the present disclosure is not limited to such examples. The use of "and" and "or" should be understood as broad (for example, as "and / or"). For example and without limitation, the use of "and" does not necessarily need to list all elements or features, and the use of "or" is intended to include end values, unless such a construction is illogical.

[0032] Although processes, systems, and methods may be described herein with respect to one or more steps in a particular order, it will be understood that such methods may be implemented with steps in a different order, with certain steps being performed simultaneously, certain steps being added, and / or certain steps being omitted.

[0033] It is intended that all that is described above or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting. Changes in detail or structure may be made without departing from the present disclosure.

[0034] It should be understood that an electronic control unit (ECU), system and / or processor as described herein may include conventional processing devices known in the art, which may be capable of executing pre-programmed instructions stored in an associated memory, all of which are executed according to the functionality described herein. To the extent that the methods described herein are embodied in software, the resulting software may be stored in an associated memory and may also constitute a device for performing such methods. Such a system or processor may also be of a type having ROM, RAM, RAM and ROM, and / or a combination of non-volatile and volatile memory, so that any software can be stored and also allows for the storage and processing of dynamically generated data and / or signals.

[0035] It should also be understood that the article according to the present disclosure may include a non-transient computer-readable storage medium having a computer program encoded thereon for implementing the logic and other functionalities described herein. The computer program may include a code for executing one or more of the methods disclosed herein. Such embodiments may be configured to be executed via one or more processors, such as a plurality of processors integrated into a single system or distributed on a communication network and connected together through a communication network, and these communication networks may be wired and / or wireless. One or more codes for implementing the features described in conjunction with one or more embodiments may cause a plurality of transistors to be changed from a first state to a second state when executed by a processor. A specific change mode (e.g., which transistors change state and which transistors do not change state) may be determined at least in part by logic and / or code.

Claims

1. An aircraft fuel tank inerting system, comprising: at least one fuel tank, the at least one fuel tank comprising a left wing fuel tank, a right wing fuel tank, and a center fuel tank; at least one vented oil tank, the at least one vented oil tank comprising a left vented oil tank and a right vented oil tank; Inert air components; at least one fluid valve connected to the at least one fuel tank, the at least one vent tank, and the inert air assembly, wherein: The at least one fluid valve comprises a first fluid valve, a second fluid valve and a third fluid valve, The first fluid valve is connected to at least the left wing fuel tank and the left vent tank, The second fluid valve is connected to at least the right wing fuel tank and the right vent tank; The third fluid valve is connected to at least the central fuel tank, The first and second fluid valves are operable to be in an open position, a closed position, and a bypass position, and The third fluid valve is operable between an open position and a closed position; and An electronic control unit, the electronic control unit being configured to: operating the first fluid valve, the second fluid valve, and / or the third fluid valve in an open position during a climb phase of flight to provide inert air to a left wing fuel tank, a right wing fuel tank, and / or a center fuel tank; If the left wing fuel tank, the right wing fuel tank, and / or the center fuel tank have reached an inertia margin above a threshold, operating the first fluid valve, the second fluid valve, and / or the third fluid valve to a closed position; and The first fluid valve and / or the second fluid valve is operated in the bypass position during a descent phase of flight to provide inert air to the left vent tank and / or the right vent tank.

2. An aircraft fuel tank inerting system according to claim 1, wherein the electronic control unit is configured to control the at least one fluid valve so that the mixed air provided from the at least one vent tank to the at least one fuel tank during the descent phase contains less than 20% oxygen.

3. The aircraft fuel tank inerting system according to claim 2, wherein the electronic control unit is configured to control the at least one fluid valve so that the mixed air provided from the at least one vent tank to the at least one fuel tank during the descent phase contains 16% or less oxygen.

4. The aircraft fuel tank inerting system of claim 1, wherein the electronic control unit is configured to close the at least one fluid valve if the electronic control unit determines that the aircraft to which the electronic control unit is connected is on the ground.

5. The aircraft fuel tank inerting system according to claim 1, wherein: The electronic control unit is further configured to operate one or more of the first fluid valve, the second fluid valve, and the third fluid valve to a closed position to enable a built-in self test to be performed.

6. A method of inerting one or more aircraft fuel tanks, the method comprising: operating at least one fluid valve of an aircraft in an open position during a climb phase of flight to provide inert air from an inert air assembly of the aircraft to at least one fuel tank of the aircraft, wherein: The at least one fluid valve comprises a first fluid valve, a second fluid valve and a third fluid valve, The at least one fuel tank includes a left wing fuel tank, a right wing fuel tank and a center fuel tank, The first fluid valve is connected to at least the left wing fuel tank, The second fluid valve is connected to at least the right wing fuel tank, The third fluid valve is connected to at least the central fuel tank, The first and second fluid valves are operable to be in an open position, a closed position, and a bypass position, and The third fluid valve is operable between an open position and a closed position; operating the at least one fluid valve in a closed position during a cruise phase of the flight if the at least one fuel tank has reached an inertia margin above a threshold; operating at least one of the first fluid valve and the second fluid valve in a bypass position during a descent phase of the flight to provide inert air to at least one vent tank of the aircraft; determining that the aircraft is on the ground; and In response to determining that the aircraft is on the ground, the at least one fluid valve is operated into a closed position.

7. The method according to claim 6, comprising: mixing inert air from the inert air assembly with ambient air in the at least one vent tank to form mixed air; as well as The mixed air is provided to the at least one fuel tank.

8. An aircraft, comprising: at least one engine; left and right; a left wing fuel tank in the left wing and a right wing fuel tank in the right wing; central fuel tank; a left ventilated fuel tank in the left wing and a right ventilated fuel tank in the right wing; Inert air components; a first fluid valve connected to the left wing fuel tank, the left vent tank, and the inert air assembly, the first fluid valve being operable in an open position, a closed position, and a bypass position; a second fluid valve connected to the right wing fuel tank, the right vent tank, and the inert air assembly, the second fluid valve being operable between an open position, a closed position, and a bypass position; a third fluid valve connected to the center fuel tank and the inert air assembly, the third fluid valve being operable between an open position and a closed position; and Electronic control unit; The electronic control unit is configured as follows: controlling the first fluid valve to provide inert air from the inert air assembly to the left wing fuel tank or to the left vent tank, controlling the second fluid valve to provide inert air from the inert air assembly to the right wing fuel tank or to the right vent tank, controlling the third fluid valve to provide inert air from the inert air assembly to the center fuel tank, operating the first fluid valve, the second fluid valve, and / or the third fluid valve in an open position during a climb phase of flight to provide inert air to a left wing fuel tank, a right wing fuel tank, and / or a center fuel tank; as well as The first fluid valve and / or the second fluid valve are operated in the bypass position during a descent phase of the flight to provide inert air to a left vent tank and / or a right vent tank, wherein mixed air is provided from the left vent tank and the right vent tank to a left wing fuel tank, a right wing fuel tank, and / or a center fuel tank.

9. The aircraft according to claim 8, wherein the electronic control unit is configured to control the first fluid valve and / or the second fluid valve so that the mixed air provided from the left ventilation tank and / or the right ventilation tank to the left wing fuel tank and / or the right wing fuel tank during the descent phase contains less than 20% oxygen.

10. The aircraft of claim 8, wherein the electronic control unit is configured to operate the first fluid valve and / or the second fluid valve in a closed position during a cruise phase of the flight if the left wing fuel tank and / or the right wing fuel tank has reached an inertia margin above a threshold.

11. The aircraft of claim 8, wherein the ECU is configured to close the first fluid valve and / or the second fluid valve if the ECU determines that the aircraft to which the ECU is connected is on the ground.

12. The aircraft of claim 8, wherein the electronic control unit is configured to control the third fluid valve to provide the inert air from the inert air assembly to the center fuel tank and to correct alignment during a climb phase of flight.

13. The aircraft of claim 8, wherein the electronic control unit is configured to operate the third fluid valve in a closed position during a cruise phase of the flight if the center fuel tank has reached an inertia margin above a threshold.

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