Method and system for automatically estimating the remaining useful life of at least one oxygen cylinder in the cockpit of an aircraft.

Abstract

Method and system for automatically estimating the remaining useful life of at least one oxygen cylinder in the cockpit of an aircraft. The system (S) includes a collection unit (10) for collecting a current oxygen pressure value ( ) from the oxygen cylinders (1), an estimation unit (20) for estimating an average degradation model, an adaptation unit (40) for adapting the average degradation model, a generation unit (50) for generating several future degradation scenarios, an estimation unit (60) for estimating, for each of the future degradation scenarios, a remaining useful life, and for generating a probability distribution of remaining useful lives (5), a transmission unit (70) for transmitting an end-of-life warning signal to an alerting device (3) if the remaining useful life of an oxygen cylinder (1) is less than a predetermined alert threshold.Figure for the abbreviation: Figure 1.

Description

Title of the invention: Method and system for automatically estimating the remaining useful life of at least one oxygen cylinder in the cockpit of an aircraft. technical field

[0001] The present invention relates to a method and a system for automatically estimating the remaining useful life of at least one oxygen cylinder in the cockpit of an aircraft. State of the art

[0002] It is known that the flight crew (or cabin crew) of an aircraft, such as a transport aircraft, have an oxygen distribution system to provide them with oxygen, particularly in the event of aircraft depressurization or smoke release. This oxygen distribution system includes, in particular, an oxygen mask for each crew member, and one or more oxygen cylinders capable of supplying these oxygen masks.

[0003] The Flight Crew Operating Manual (FCOM) requires that this crew oxygen distribution system be tested before each flight of the aircraft. Under normal conditions (in the absence of leaks), a slight decrease in oxygen pressure is observed after each flight in the oxygen cylinder(s). The test consists of comparing the pressure indicated on the oxygen cylinder, which is representative of the amount of oxygen available, to a minimum threshold value. When this minimum threshold value is reached, the oxygen cylinder(s) in use are either refilled or replaced.

[0004] In the context of the present invention, the remaining useful life of an oxygen cylinder is understood to mean the time or duration remaining until the air cylinder reaches a level from which a maintenance action must be carried out, namely either a replacement of this oxygen cylinder (with another oxygen cylinder having a sufficient capacity), or a refilling of the oxygen cylinder with oxygen to reach a sufficient capacity.

[0005] However, taking into account a simple threshold value to evaluate the oxygen capacity of the bottle cannot help to capture different degradation behaviors and predict degradation in advance.

[0006] Various common solutions are known to try to remedy this drawback which are, however, not entirely satisfactory, namely in particular:

[0007] - filtering methods, for example Kalman filtering, which do not capture variability in the long term.

[0008] - data-driven models such as ARMA or neural networks do not do not take into account specific technical knowledge (on degradation) to predict an accurate remaining useful life of the health indicator (namely the oxygen pressure in the bottle).

[0009] Neural networks require an enormous amount of training data which is not available and is not easily interpretable

[0010] No estimate of the remaining useful life of the cockpit crew oxygen cylinder.

[0011] There is therefore a need to find a solution that allows for anticipating maintenance of the oxygen cylinder(s). Description of the invention

[0012] The present invention relates to a method for automatically estimating the remaining useful life of at least one oxygen cylinder in an aircraft cockpit.

[0013] According to the invention, the method comprises at least the following steps implemented for a typical aircraft flight iteratively for each oxygen cylinder: - a collection step, implemented by a collection unit, to collect a current oxygen pressure value from the oxygen cylinder(s) and to correct the current oxygen pressure value in order to obtain a corrected current pressure value, - a first estimation step, implemented by a first estimation unit, to estimate an average degradation model from pressure values ​​collected and corrected on a fleet comprising a predetermined number of aircraft, - an adaptation step, implemented by an adaptation unit, to adapt the average degradation model from the corrected current pressure value and previously collected and corrected oxygen pressure values ​​for X previous flights, where X is a predetermined number of flights preceding the current flight, - a generation step, implemented by a generation unit, to generate several future degradation scenarios from the corrected current pressure value and from the oxygen pressure values ​​collected and corrected from the previous X flights, - a second estimation step, implemented by a second estimation unit, to estimate, for each of the future degradation scenarios, a duration of remaining useful life, and to generate a probability distribution of remaining useful lives from the remaining useful lives generated for each of the future degradation scenarios, - a first transmission step, implemented by a first transmission unit, to transmit an end-of-life alert signal to an alerting device to alert an operator if a remaining useful life of one or more oxygen cylinders is less than a predetermined alert threshold based on the probability distribution of remaining useful lives.

[0014] Thus, thanks to the invention, it is possible to automatically determine the remaining useful life of at least one oxygen cylinder in the cockpit of an aircraft, by learning the degradation behavior using past data and proposes a probabilistic assessment of its end of life before maintenance.

[0015] Furthermore, the corrected current pressure value is obtained in the collection step from the current oxygen pressure value, from an outside current temperature of the aircraft and a current temperature of the aircraft cockpit.

[0016] In addition, the method includes a filtering step preceding the adaptation step, implemented by a filtering unit, to filter the corrected current pressure value and the oxygen pressure values ​​collected and corrected from the previous X flights and to determine a trend in the oxygen pressure value for the current flight and the previous X flights.

[0017] Furthermore, the adaptation step further includes a calculation substep, implemented by a calculation subunit, to calculate a pressure variation for the current flight and for the X previous flights from the trend of the oxygen pressure value determined for the current flight and the X previous flights.

[0018] In addition, the adaptation step includes: - a calculation substep, implemented by a calculation subunit, to calculate a current expected pressure value for the current flight and an expected pressure value for the previous X flights from the collected and corrected oxygen pressure values ​​determined for the previous X flights and pressure variations determined for the previous X flights, - a comparison substep, implemented by a comparison subunit, to determine, for the current flight and for each of the X previous flights respectively, a difference between the corrected pressure value and the expected pressure value, - a compensation sub-step, implemented by a compensation sub-unit, to compensate for the corrected current pressure value and the collected and corrected oxygen pressure values ​​determined for the previous X flights, if said difference determined for the current flight or at least one of the X flights is positive and exceeds a first threshold value, the oxygen pressure values ​​collected and corrected for the previous X flights being compensated by adding said difference to said oxygen pressure values ​​collected and corrected for the previous X flights, if said difference determined for the current flight or at least one of the X previous flights is negative and exceeds a second threshold value, the oxygen pressure values ​​collected and corrected for the X previous flights are compensated by adding said difference to said oxygen pressure values ​​collected and corrected for the X previous flights.

[0019] Advantageously, the method further includes a second transmission step, implemented by a second transmission unit, to transmit a pressure drop warning signal to the warning device if a flight of the aircraft among the current flight and the X previous flights has as its departure airport the same arrival airport as the flight preceding it, in the case where said difference determined for the current flight or at least one of the X previous flights is negative and exceeds a second threshold value.

[0020] Furthermore, the method includes a third transmission step, implemented by a third transmission unit, to transmit a leak alert signal to the alert device, in the event that said difference determined for the current flight or at least one of the X previous flights is less than a third threshold value.

[0021] The invention also relates to an automatic estimation system for the remaining useful life of at least one oxygen cylinder in an aircraft cockpit.

[0022] According to the invention, the system comprises at least: - a collection unit, configured to collect a current oxygen pressure value from the oxygen cylinder(s) and to correct the current oxygen pressure value to obtain a corrected current pressure value, - a first estimation unit, configured to estimate an average degradation model from pressure values ​​collected and corrected on a fleet comprising a predetermined number of aircraft, - an adaptation unit, configured to adapt the average degradation model from the corrected current pressure value and oxygen pressure values ​​collected and corrected for X previous flights, where X is a predetermined number of flights preceding the current flight, - a generation unit, configured to generate several future degradation scenarios from the corrected current pressure value and from the oxygen pressure values ​​collected and corrected from the previous X flights, - a second estimation unit, configured to estimate, for each of the future degradation scenarios, a remaining useful life, and to generate a probability distribution of remaining useful lives from the remaining useful lives generated for each of the future degradation scenarios, - a first transmission unit, configured to transmit an end-of-life alert signal to an alerting device to alert an operator if the remaining useful life of one or more oxygen cylinders is less than a predetermined alert threshold based on the probability distribution of remaining useful lives.

[0023] In addition, the corrected current pressure value is obtained by the collection unit from the current oxygen pressure value, from an outside current temperature of the aircraft and a current temperature of the aircraft cockpit.

[0024] In addition, the system includes a filtering unit, configured to filter the corrected current pressure value and the collected and corrected oxygen pressure values ​​from the previous X flights and to determine a trend in the oxygen pressure value for the current flight and the previous X flights.

[0025] Furthermore, the adaptation unit further includes a calculation subunit, configured to calculate a pressure variation for the current flight and for the X previous flights from the trend of the oxygen pressure value determined for the current flight and the X previous flights.

[0026] In addition, the adaptation unit comprises: - a determination subunit, configured to determine a current expected pressure value for the current flight and an expected pressure value for the previous X flights from the collected and corrected oxygen pressure values ​​determined for the previous X flights and pressure variations determined for the previous X flights, - a comparison subunit, configured to determine, for the current flight and for each of the X previous flights respectively, a difference between the corrected pressure value and the expected pressure value, - a compensation subunit, configured to compensate for the corrected current pressure value and the collected and corrected oxygen pressure values ​​determined for the previous X flights, - if said difference determined for the current flight or at least one of the X previous flights is positive and exceeds a first threshold value, the oxygen pressure values ​​collected and corrected for the X previous flights are compensated by adding said difference to said oxygen pressure values ​​collected and corrected for the X previous flights, - if the difference determined for the current flight or at least one of the X previous flights is negative and exceeds a second threshold value, the pressure values oxygen collected and corrected for the previous X flights being compensated by adding said difference to said oxygen pressure values ​​collected and corrected for the previous X flights.

[0027] Advantageously, the system further includes a second transmission unit, configured to transmit a pressure drop warning signal to the warning device if a flight of the aircraft among the current flight and the X previous flights has as its departure airport the same arrival airport as the flight preceding it, in the event that said difference determined for the current flight or at least one of the X previous flights is negative and exceeds a second threshold value.

[0028] In addition, the system includes a third transmission unit, configured to transmit a leak alert signal to the alert device, in the event that said difference determined for the current flight or at least one of the X previous flights is less than a third threshold value.

[0029] The invention also relates to an aircraft, such as a transport aircraft, comprising an automatic estimation system for the remaining useful life of at least one oxygen cylinder in the cockpit of an aircraft, such as that specified above. Brief description of the figures

[0030] The accompanying figures will clearly illustrate how the invention can be implemented. In these figures, identical reference numerals designate similar elements.

[0031] Figure [1] is a schematic representation of the estimation system according to one embodiment,

[0032] Figure [Fig. 2] is a schematic representation of the estimation process according to one embodiment,

[0033] Figure [Fig. 3] represents an aircraft carrying the estimation system,

[0034] Figure 4 is a graph representing curves corresponding to scenarios of future degradation

[0035] Figure 5 represents an example of a probability distribution of remaining useful lives,

[0036] Figure 6 represents a graph in which the oxygen pressure values ​​are compensated after filling an oxygen cylinder,

[0037] Figure [Fig.7] represents a graph in which the oxygen pressure values ​​are compensated after a pressure drop in the oxygen cylinder. Detailed description

[0038] A system S such as that shown in a particular embodiment in [Fig.1] is intended to automatically estimate a remaining useful life of at least one oxygen cylinder 1 in a cockpit 2 of an AC aircraft.

[0039] The S system can be carried on board an aircraft, in particular a transport aircraft ([Fig.3]).

[0040] The system comprises at least: - a collection unit 10 COLL (COLL for "collecting unit" in English), - a first estimation unit 20 ESTIM1 (ESTIM for "estimating unit" in English), - an adaptation unit 40 ADAPT (ADAPT for "adapting unit" in English), - a 50 GEN generation unit (GEN stands for "generating unit"), - a second 60 ESTIM2 estimation unit and - a first transmission unit 70 TRANSI (TRANS for "transmitting unit" in English).

[0041] These units are implemented by a computer, such as an avionics computer.

[0042] The collection unit 10 is configured to collect a current oxygen pressure value Poxy (in bar) from the oxygen cylinder(s) 1 and to correct the current oxygen pressure value Poxy in order to obtain a corrected current pressure value Pc.

[0043] The collection unit 10 can retrieve the current oxygen pressure values ​​Poxy of each of the oxygen cylinders 1 from a database 9 DB (DB for "database" in English) in which the current oxygen pressure values ​​Poxy of each of the oxygen cylinders 1 are stored.

[0044] According to one embodiment, each of the oxygen cylinders 1 has a pressure sensor C connected to the database 9. The collection unit 10 thus collects the current oxygen pressure values ​​Poxy of each of the oxygen cylinders 1 from the database 9.

[0045] In another embodiment, an operator enters, using an input device, the current oxygen pressure values ​​Poxy read on each of the oxygen cylinders 1 so that they are stored in the database 9.

[0046] The collection unit 10 is also configured to correct the current oxygen pressure value Poxy of each of the oxygen cylinders 1.

[0047] The corrected current pressure value Pc is obtained by the collection unit 10 from the current oxygen pressure value Poxy, from an outside current temperature Tair (in °C) of the aircraft AC and a cockpit current temperature TCOckPit (in °C) of the aircraft AC. The cockpit current temperature Tcockpit of the aircraft AC may correspond to a temperature measured in the cockpit or to a temperature measured in an air mixer of an air conditioning system in the cockpit.

[0048] The relationship for obtaining the corrected current pressure value Pc can cor- Answer the following equation:

[0049] 272+

[0050] The first estimation unit 20 is configured to estimate an average degradation model from pressure values ​​collected and corrected over a fleet comprising a predetermined number of AC aircraft.

[0051] The degradation model may correspond to a predictive model. For example, the degradation model may be estimated from the fleet comprising a predetermined number of AC aircraft by fitting a polynomial curve to the pressure values ​​collected on the fleet of AC aircraft.

[0052] The adaptation unit 40 is configured to adapt the average degradation model based on the corrected current pressure value Pc and collected and corrected oxygen pressure values ​​Pci for X previous flights. X and a predetermined number of flights preceding the current flight. The previously collected and corrected oxygen pressure values ​​Pc for X previous flights correspond to the collected and corrected oxygen pressure values ​​for X previous flights.

[0053] Without limitation, the predetermined number (natural integer) X of previous flights is greater than or equal to 5, advantageously greater than or equal to 10. By way of non-limiting example, the predetermined number X of previous flights is between 5 and 15. For example, the predetermined number X of previous flights is equal to 8.

[0054] The generation unit 50 is configured to generate several future degradation scenarios from the corrected current pressure value Pc and from the collected and corrected oxygen pressure values ​​Pci of the previous X flights.

[0055] Figure 4 represents the collected and corrected oxygen pressure values ​​Pci for X previous flights to which several curves 6 are added. Each of the curves 6 is determined for a future degradation scenario using the average degradation model.

[0056] The second estimation unit 60 is configured to estimate, for each of the future degradation scenarios, a remaining useful life, and to generate a probability distribution of remaining useful lives 5 from the remaining useful lives generated for each of the future degradation scenarios.

[0057] Figure 4 shows a desired minimum working pressure L. The useful life remaining for each scenario corresponds to the useful life for the desired minimum working pressure.

[0058] Figure 5 represents an example of a probability distribution of useful lives remaining 5. This probability distribution of remaining useful life 5 corresponds to a time window that allows an airline to plan and adapt maintenance. In the example of [Fig. 5], the filling of Oxygen cylinder 1 should be filled between day t+22 and day t+32. The airline may decide that the oxygen cylinder can be filled at t+30 and not at t+22.

[0059] The first transmission unit 70 is configured to transmit an end-of-life warning signal to an alerting device 3 to alert an operator if the remaining useful life of one or more oxygen cylinders 1 is less than a predetermined warning threshold based on the probability distribution of remaining useful lives 5. The warning signal may indicate which oxygen cylinder 1 has a remaining useful life less than the predetermined warning threshold. The predetermined warning threshold may be defined by the airline that operates the aircraft AC.

[0060] For example, the alert device 3 corresponds to a display device configured to display an end-of-life alert from the end-of-life alert signal transmitted by the first transmission unit 70.

[0061] Advantageously, the system S further comprises a filtering unit 30 configured to filter the corrected current pressure value Pc and the collected and corrected oxygen pressure values ​​Pcj from the previous X flights and to determine a trend T{ of the oxygen pressure value for the current flight and the previous X flights. The filtering unit is implemented by the computer.

[0062] The filtering unit 30 can implement a Hodrick-Prescott filter known to a person skilled in the art.

[0063] Furthermore, the adaptation unit 40 may further comprise a first computing subunit 410 COMPUT1 (COMPUT stands for "computing subunit"). The computing subunit 410 is configured to calculate a pressure variation (A) for the current flight and for the X previous flights from the trend (Tj) of the oxygen pressure value determined for the current flight and the X previous flights.

[0064] The relationship for obtaining the pressure variation AP, for the typical flight, can be represented by the following equation:

[0065] _ E;(FH;-F«)(rT)

[0066] in which: Fn { corresponds to a flight index, thus Fn, = i, Fn corresponds to the average of the Fn^ indices for the predetermined number of previous flights, Tj corresponds to the trend Tj of the oxygen pressure value for flight i of the X previous flights, T corresponds to the average of the trend T, for the predetermined number X of previous flights.

[0067] The adaptation unit 40 may further comprise: - a calculation subunit 420 COMPUT2, - a comparison subunit 430 COMP (COMP for "comparing unit" in English) and - a 440 COMPENS (COMPENS for "compensating unit" in English).

[0068] The calculation subunit 420 is configured to calculate a current expected pressure value Pcepi for the current flight and an expected pressure value Pcepi for the X previous flights from the collected and corrected oxygen pressure values ​​Pcp\ determined for the X previous flights and pressure variations A PiA determined for the X previous flights.

[0069] The expected current pressure value Pcepi can be determined using the following expression: Pcepi = AP^ • Fn^ ( Pcc^ - AP^ • Fn^ ), where: Pcepi corresponds to the current expected pressure value

[0070] The comparison subunit 430 is configured to determine for the current flight and for each of the X previous flights respectively a difference Pcdifi between the corrected pressure value P a and the expected pressure value Pcepi.

[0071] The expression for the difference is as follows: P edi fi — Pci Pcepi, in which: P edi fi corresponds to the said difference for flight i, P à corresponds to the corrected pressure value for flight i, Pcepi corresponds to the expected pressure value for flight i.

[0072] The compensation subunit 440 is configured to compensate for the corrected current pressure value Pc and the collected and corrected oxygen pressure values ​​Pcj determined for the previous X flights.

[0073] The previously collected and corrected oxygen pressure values ​​are compensated in the following manner.

[0074] If said difference P edi fi determined for the current flight or at least one of the X flights If the previous value is positive and exceeds a first threshold value OxyRT, the collected and corrected oxygen pressure values ​​Pi for the previous X flights are compensated by adding the difference Pedifi to the collected and corrected oxygen pressure values ​​Pi for the previous X flights. This corresponds to an increase in oxygen pressure in oxygen cylinder 1. This increase may correspond to a refill of oxygen cylinder 1 or a replacement of the oxygen cylinder with another full oxygen cylinder.

[0075] Figure 6 shows a curve 7 of the oxygen pressure values ​​collected and corrected before filling the oxygen cylinder 1 with oxygen. At point 11, Referred to as the filling point, the collected and corrected oxygen pressure values ​​(Pci) enclosed in box 12 are compensated as explained above. Curve 8 represents the curve of collected and corrected oxygen pressure values ​​after filling oxygen cylinder 1. The collected and corrected oxygen pressure values ​​before filling the previous X flights (enclosed in box 13) are also included in curve 8 after compensation.

[0076] If the difference Pedi determined for the current flight or at least one of the X preceding flights is negative and exceeds a second threshold value OxyDT, the collected and corrected oxygen pressure values ​​Pci for the X preceding flights are compensated by adding the difference Pcdifi (which is negative) to the collected and corrected oxygen pressure values ​​Pci for the X preceding flights. This condition corresponds to a pressure drop in the oxygen cylinder 1.

[0077] Figure 7 shows a curve 16 of the oxygen pressure values ​​collected and corrected before the oxygen pressure drop in the oxygen cylinder 1. At point 12, called the drop point, the collected and corrected oxygen pressure values ​​Pci enclosed by the frame 14 are compensated as explained above. Curve 17 corresponds to the curve of the oxygen pressure values ​​collected and corrected after the pressure drop in the oxygen cylinder 1. The oxygen pressure values ​​collected and corrected before the pressure drop of the previous X flights (enclosed by the frame 15) are also included in curve 17 after compensation.

[0078] The system S may further include a second transmission unit 71, configured to transmit a pressure drop warning signal to the warning device 3 if a flight of aircraft AC among the current flight and the X previous flights has as its departure airport the same arrival airport as the flight preceding it, in the case where said difference Pcdifi determined for the current flight or at least one of the X previous flights is negative and exceeds a second threshold value OxyDT.

[0079] The system S may include a third transmission unit 72, configured to transmit a leak warning signal to the warning device 3, in the event that said difference Pcdifi determined for the current flight or at least one of the previous X flights is less than a third threshold value OxyLTl.

[0080] The invention also relates to a method for automatically estimating the remaining useful life of at least one oxygen cylinder 1 in a cockpit 2 of an AC aircraft ([Fig.2]).

[0081] Said method comprises at least the following steps implemented for a typical flight of aircraft AC iteratively for each oxygen cylinder 1: - a collection step El, implemented by the collection unit 10, to collect a current oxygen pressure value Poxy from the(s) oxygen cylinders 1 and to correct the current oxygen pressure value Poxy to obtain a corrected current pressure value Pc, - a first estimation step E2, implemented by the first estimation unit 20, to estimate an average degradation model from pressure values ​​collected and corrected over a fleet comprising a predetermined number of aircraft, - an adaptation step E4, implemented by adaptation unit 40, to adapt the average degradation model from the corrected current pressure value Pc and previously collected and corrected oxygen pressure values ​​Pci for X previous flights, X being a predetermined number of flights preceding the current flight, - a generation step E5, implemented by generation unit 50, to generate several future degradation scenarios from the corrected current pressure value Pc and from the collected and corrected oxygen pressure values ​​Pci of the previous X flights, - a second estimation step E6, implemented by the second estimation unit 60, to estimate, for each of the future degradation scenarios, a remaining useful life, and to generate a probability distribution of remaining useful lives 5 from the remaining useful lives generated for each of the future degradation scenarios, - a first transmission step E7, implemented by the first transmission unit 70, to transmit an end-of-life alert signal to an alert device 3 to alert an operator if a remaining useful life of one or more oxygen cylinders 1 is less than a predetermined alert threshold based on the probability distribution of remaining useful lives 5.

[0082] The method may include a filtering step E3 preceding the adaptation step E4, implemented by the filtering unit 30, to filter the corrected current pressure value Pc and the collected and corrected oxygen pressure values ​​Pci from the previous X flights and to determine a trend Ti of the oxygen pressure value for the current flight and the previous X flights.

[0083] The adaptation step E4 may further include a calculation substep E41, implemented by the calculation subunit 410, to calculate a pressure variation AP{ for the current flight and for the X previous flights from the trend T, of the value of the oxygen pressure determined for the current flight and the X previous flights.

[0084] The adaptation step E4 may further include: - a calculation sub-step E42, implemented by calculation sub-unit 420, to calculate a current expected pressure value Pcepi for the current flight and an expected pressure value Pcepi for the X previous flights from the collected and corrected oxygen pressure values ​​Pcp determined for the X previous flights and pressure variations A PiA determined for the X previous flights, - a comparison sub-step E43, implemented by the comparison sub-unit 430, to determine for the current flight and for each of the X previous flights respectively a difference Pcdifi between the corrected pressure value Pct and the expected pressure value Pcepi, - a compensation sub-step E44, implemented by the compensation sub-unit 440, to compensate for the corrected current pressure value Pc and the collected and corrected oxygen pressure values ​​Pci determined for the previous X flights.

[0085] The method may further include a second transmission step E71, implemented by the second transmission unit 71, to transmit a pressure drop warning signal to the warning device 3 if a flight of aircraft AC among the current flight and the X previous flights has as its departure airport the same arrival airport as the flight preceding it, in the case where said difference Pcdifi determined for the current flight or at least one of the X previous flights is negative and exceeds a second threshold value OxyDT.

[0086] The method may include a third transmission step E72, implemented by the third transmission unit 72, to transmit a leak warning signal to the warning device 3, in the event that said difference Pcdtfi determined for the current flight or at least one of the X previous flights is less than a third threshold value OxyLTL

[0087] System S and the method have at least the following advantages: - To propose a decision support tool with a quantifiable uncertainty to alert or not to the replacement of an oxygen cylinder 1 with a controlled level of risk, namely: • Improved spare parts management, • Improved lifecycle management of an oxygen cylinder 1, - The process uses a pre-designed model augmented by the use of data in service. - The process requires little historical data and only partial knowledge of the degradation.

Claims

1. Claims Method for automatically estimating a remaining useful life of at least one oxygen bottle (1) in a cockpit (2) of an aircraft (AC), characterized in that it comprises at least the following steps implemented for a current flight of the aircraft (AC) in an iterative manner for each oxygen bottle (1): - a collection step (El), implemented by a collection unit (10), to collect a current oxygen pressure value ( / 'oxy) from the oxygen cylinder(s) (1) and to correct the current oxygen pressure value (Poxy) in order to obtain a corrected current pressure value (Pc), - a first estimation step (E2), implemented by a first estimation unit (20), to estimate an average degradation model from pressure values ​​collected and corrected on a fleet comprising a predetermined number of aircraft, - an adaptation step (E4), implemented by an adaptation unit (40), to adapt the average degradation model from the corrected current pressure value (Pc) and previously collected and corrected oxygen pressure values ​​(Pct) for X previous flights, X being a predetermined number of flights preceding the current flight, - a generation step (E5), implemented by a generation unit (50), to generate several future degradation scenarios from the corrected current pressure value (Pc) and from the collected and corrected oxygen pressure values ​​(P„) of the X previous flights, - a second estimation step (E6), implemented by a second estimation unit (60), to estimate, for each of the future degradation scenarios, a remaining useful life, and to generate a probability distribution of remaining useful lives (5) from the remaining useful lives generated for each of the future degradation scenarios, - a first transmission step (E7), implemented by a first transmission unit (70), to transmit a end of life alert signal to an alert device (3) for alerting an operator if a remaining useful life of one or more oxygen cylinders (1) is less than a predetermined alert threshold based on the probability distribution of remaining useful lives (5).

2. Method according to claim 1, characterized in that the corrected current pressure value (Pc) is obtained in the collection step (El) from the current oxygen pressure value (Poxy), from a current external temperature (T of the aircraft (AC) and a current temperature of the cockpit (Tcockpit) of the aircraft (AC).

3. Method according to one of claims 1 and 2, characterized in that it comprises a filtering step (E3) preceding the adaptation step (E4), implemented by a filtering unit (30), to filter the corrected current pressure value (Pc) and the collected and corrected oxygen pressure values ​​(Pci) of the X previous flights and to determine a trend (T,) of the oxygen pressure value for the current flight and the X previous flights.

4. Method according to one of claims 1 to 3, characterized in that the adaptation step (E4) further comprises a calculation sub-step (E41), implemented by a calculation sub-unit (410), for calculating a pressure variation (AP^ for the current flight and for the X previous flights from the trend (Pj) of the value of the oxygen pressure determined for the current flight and the X previous flights.

5. Method according to one of claims 1 to 4, characterized in that the adaptation step (E4) further comprises: - a calculation sub-step (E42), implemented by a calculation sub-unit (420), for calculating a current expected pressure value (Pcept) for the current flight and an expected pressure value (P ce pi) for the X previous flights from the collected and corrected oxygen pressure values ​​(PciA) determined for the X previous flights and pressure variations (A PiA) determined for the X previous flights, - a comparison sub-step (E43), implemented by a comparison sub-unit (430), for determining for the flight current and for each of the X previous flights respectively a difference (Pcdifi) between the corrected pressure value (P to ) and the expected pressure value (Pcepf), - a compensation sub-step (E44), implemented by a compensation sub-unit (440), to compensate the corrected current pressure value (Pc) and the collected and corrected oxygen pressure values ​​(Pci) determined for the X previous flights, if said difference (Pcdifi) determined for the current flight or at least one of the X previous flights is positive and exceeds a first threshold value (OxyRT), the collected and corrected oxygen pressure values ​​(Pci) for the X previous flights being compensated by adding said difference (Pcdifi) to said collected and corrected oxygen pressure values ​​(Pci) for the X previous flights, if said difference (Pcdifi) determined for the current flight or at least one of the X previous flights is negative and exceeds a second threshold value (OxyDT),the collected and corrected oxygen pressure values ​​(Pd) for the previous X flights being compensated by adding said difference (Pcdifi) to said collected and corrected oxygen pressure values ​​(Pci) for the previous X flights.,

6. Method according to claim 5, characterized in that it further comprises a second transmission step (E71), implemented by a second transmission unit (71), for transmitting a pressure drop alert signal to the alert device (3) if a flight of the aircraft (AC) among the current flight and the X previous flights has as departure airport the same arrival airport as the flight which precedes it, in the case where said difference (Pcdifi) determined for the current flight or at least one of the X previous flights is negative and exceeds a second threshold value (OxyDT).

7. Method according to one of claims 5 and 6, characterized in that it comprises a third transmission step (E72), implemented by a third transmission unit (72), to transmit a leak alert signal to the alert device (3), in the case where said difference (Pcdifi) determined for the current flight or at least one of the X previous flights is less than a third threshold value (OxyLTl).

8. System for automatically estimating a remaining useful life of at least one oxygen bottle (1) in a cockpit (2) of an aircraft (AC), characterized in that it comprises at least: - a collection unit (10), configured to collect a current oxygen pressure value (Pon) from the oxygen cylinder(s) (1) and to correct the current oxygen pressure value (P<«>) in order to obtain a corrected current pressure value (Pc), - a first estimation unit (20), configured to estimate an average degradation model from pressure values ​​collected and corrected on a fleet comprising a predetermined number of aircraft, - an adaptation unit (40), configured to adapt the average degradation model from the corrected current pressure value (Pe) and collected and corrected oxygen pressure values ​​(Pcj) for X previous flights, X being a predetermined number of flights preceding the current flight, - a generation unit (50), configured to generate several future degradation scenarios from the corrected current pressure value (Pc) and from the collected and corrected oxygen pressure values ​​(P a) of the X previous flights, - a second estimation unit (60), configured to estimate, for each of the future degradation scenarios, a remaining useful life, and to generate a probability distribution of remaining useful lives (5) from the remaining useful lives generated for each of the future degradation scenarios, - a first transmission unit (70), configured to transmit an end-of-life alert signal to an alert device (3) to alert an operator if a remaining useful life of one or more oxygen cylinders (1) is lower than a predetermined alert threshold based on the probability distribution of remaining useful lives (5).

9. System according to claim 8, characterized in that the corrected current pressure value (Pc) is obtained by the collection unit (10) from the current oxygen pressure value (Poxy), from a current outside temperature (Tair) of the aircraft (AC) and a current cockpit temperature (P cockpit) of the aircraft (AC).

10. System according to one of claims 8 and 9, characterized in that it comprises a filtering unit (30), configured to filter the corrected current pressure value (Pc) and the collected and corrected oxygen pressure values ​​(Pcj) of the X previous flights and to determine a trend (T i) of the oxygen pressure value for the current flight and the X previous flights.

11. System according to one of claims 8 to 10, characterized in that the adaptation unit (40) further comprises a calculation sub-unit (410), configured to calculate a pressure variation (A jP;) for the current flight and for the X previous flights from the trend (Pi) of the value of the oxygen pressure determined for the current flight and the X previous flights.

12. System according to one of claims 8 to 11, characterized in that the adaptation unit (40) further comprises: - a determination sub-unit (420), configured to determine a current expected pressure value (Pcepi) for the current flight and an expected pressure value (P ce pi) for the X previous flights from the collected and corrected oxygen pressure values ​​(Pci-\) determined for the X previous flights and pressure variations (A determined for the X previous flights, - a comparison sub-unit (430), configured to determine for the current flight and for each of the X previous flights respectively a difference (Pedi fi) between the corrected pressure value (Pci) and the expected pressure value (Pcepi), - a compensation sub-unit (440),configured to compensate the corrected current pressure value (Pc) and the collected and corrected oxygen pressure values ​​(Pci) determined for the X previous flights, - if said difference (Pedi fi) determined for the current flight or at least one of the X previous flights is positive and exceeds one, first threshold value (OxyRT), the collected and corrected oxygen pressure values ​​(P to) for the X previous flights being compensated by adding said difference (Pcdifi) to said collected and corrected oxygen pressure values ​​(Pci) for the X previous flights, - if said difference (Pcdifi) determined for the current flight or at least one of the X previous flights is negative and exceeds a second threshold value (OxyDT), the collected and corrected oxygen pressure values ​​(Pcj) for the X previous flights being compensated by adding said difference (Pcdifi) to said collected and corrected oxygen pressure values ​​(Pci) for the X previous flights.

13. System according to claim 12, characterized in that it further comprises a second transmission unit (71), configured to transmit a pressure drop alert signal to the alert device (3) if a flight of the aircraft (AC) among the current flight and the X previous flights has as departure airport the same arrival airport as the flight which precedes it, in the case where said difference (Pcdifi) determined for the current flight or at least one of the X previous flights is negative and exceeds a second threshold value (OxyDT).

14. System according to one of claims 12 and 13, characterized in that it comprises a third transmission unit (72), configured to transmit a leak alert signal to the alert device (3), in the case where said difference (Pcdifi) determined for the current flight or at least one of the X previous flights is less than a third threshold value (OxyLTl).

15. Aircraft, characterized in that it comprises a system for automatically estimating a remaining useful life of at least one oxygen bottle in a cockpit of an aircraft, such as that specified under any one of claims 8 to 14.

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