FR3087887A1 - DEVICE AND METHOD FOR MONITORING THE LIFETIME OF HYDRAULIC EQUIPMENT OF AN AIRCRAFT - Google Patents

Abstract

The invention relates to a device for monitoring the life of at least one hydraulic equipment item of an aircraft subjected to variations in hydraulic pressure (P) in flight, the device comprising an interface for receiving measurement data representative of the hydraulic pressure (P) of the equipment as a function of time (t) in flight, The invention is characterized in that the device comprises a processing device, comprising a means for detecting, from the measurement data, a stress (SOLLEND) in pressure (P) of a damaging nature, defined by the fact that the pressure (P) comprises an increase (ΔPAUG) in pressure, greater than a determined threshold (SΔP) of damage greater than zero, followed by a decrease (ΔPDIM) in pressure greater than the determined threshold (SΔP) of damage, and a counting means for counting the number (MEND) of stresses (SOLLEND) in pressure (P) of a damaging nature.

Description

The invention relates to a device and a method for monitoring the life of at least one hydraulic equipment item of an aircraft subjected to variations in hydraulic pressure in flight.

One field of application of the invention is the maintenance of aircraft, in particular those equipped with turbojets.

In particular, the hydraulic equipment can be a heat exchanger, positioned in the secondary flow as an additional source of cooling for this equipment, in an aircraft turbojet. Such a heat exchanger is known for example from document EP-A -1 916 399.

The object of the invention is to obtain a device and a method for monitoring the life of at least one piece of equipment, making it possible to monitor the fatigue of the hydraulic equipment, in order to be able to carry out preventive maintenance on this equipment.

15 In fact, such preventive maintenance, consisting in monitoring the state of health of the equipment in order to change or repair it sufficiently early, makes it possible to reduce in-flight failures (in English: In-Flight Shut Down), the rate aircraft ground stop (in English: Aircrat't On Ground) and the cancellation and delay rate of flights (in English: Delays & Cancellations), this reduction being crucial for the profitability of the aircraft. 'a turbojet.

To this end, a first object of the invention is a device for monitoring the life of at least one hydraulic equipment item of an aircraft subjected to variations in flight hydraulic pressure, the device comprising an interface for receiving data from measurement representative of the hydraulic pressure of the equipment as a function of the time in flight, characterized in that the device comprises a processing device, comprising a means for detecting, from the measurement data, a pressure load of a damaging nature , defined by the fact that the pressure comprises an increase in pressure, greater than a determined threshold of damage greater than zero, followed by a decrease in pressure greater than the determined threshold of damage, 2 and a counting means for counting the number of damaging pressure stresses.

The fatigue wear of the hydraulic equipment of aircraft engines over the hours of operation of the engine is directly linked to the number of stresses to which they are subjected and to the pressure level reached during each cycle.

The invention thus makes it possible to count several pressure stresses of a damaging nature by theft, which can then each be quantified by this number of stresses as being more or less damaging to the hydraulic equipment.

The invention makes it possible to develop aging predictors, allowing the introduction of means dedicated to predictive maintenance.

The number of damaging pressure stresses makes it possible to calculate the real lifespan of new equipment coming into operation.

The invention thus enables a statistical verification of the service life observed in service for the hydraulic equipment of the aircraft, a categorization of the aircraft engines fitted with the hydraulic equipment in order to know which are the aircraft fleets and the aircraft. conditions of use generating the most fatigue of the equipment, and consequently causing the fastest aging of the equipment.

The data of the number of damaging pressure stresses produced by the invention, coupled with information relating to the conditions under which the fleets are operating, allow estimates to be made as to the aging and remaining life of hydraulic equipment, thus allowing the implementation of predictive maintenance.

In the event of quality problems, improper repairs or rework 25 or use of parts not guaranteed or provided by unofficial sources, the statistical knowledge of the rate of aging of the equipment provided by the in-service use of the The invention will further facilitate the demonstration of the deviation in fatigue behavior from the reference parts and the detection of anomalies relating to the service life of an item of equipment.

The invention allows the collection and storage of a very large mass of data relating to the pressure levels effectively observed at the level of the 3 hydraulic equipment, which makes it possible to specify as accurately as possible the need for equipment withstand on future programs. .

According to one embodiment of the invention, the monitoring device comprises an estimator for determining the hydraulic pressure of the equipment from values of another hydraulic pressure of another equipment of the aircraft as a function of time. , which are included in the measurement data and which have been measured by a measurement sensor provided on this other equipment.

According to one embodiment of the invention, the processing device comprises an alert means for sending an alert message to the outside, when the number of damaging pressure requests is greater than or equal to a first predefined alert threshold or when the number of pressure requests of a damaging nature, accumulated over several flights, is greater than or equal to a second predefined alert threshold or when a slope of the number of pressure requests of a damaging nature, cumulative over several flights, relative to a number of flights of the predetermined aircraft is greater than or equal to a third predefined alert threshold.

A second object of the invention is a method for monitoring the life of at least one hydraulic equipment item of an aircraft subjected to variations in hydraulic pressure in flight, a method in which one receives, during a step of reception on a reception interface of measurement data representative of the hydraulic pressure of the equipment as a function of time in flight, characterized in that during a detection step, a processing device is detected, from the measurement data, a damaging pressure load, defined by the fact that the pressure includes an increase in pressure, greater than a determined damage threshold greater than zero, followed by a decrease in pressure greater than the threshold determined damage, during a counting step, the processing device counts the number of damaging pressure stresses.

According to one embodiment of the invention, in the event of missing pressure values between present pressure values which are spaced 4 times apart, replacement pressure values varying in a linear fashion between these pressure values are inserted. pressure present.

According to one embodiment of the invention, the measurement data comprise values of another hydraulic pressure of another item of equipment of the aircraft as a function of time, having been measured by a measurement sensor provided on this other. equipment before the reception step, the method comprising an estimation step, which is subsequent to the reception step and prior to the detection step and during which it is estimated by an estimator of the processing device, the hydraulic pressure of the equipment from the values of the other hydraulic pressure of the other equipment of the aircraft According to one embodiment of the invention, during a warning step subsequent to the step counting, an alert message is sent to the outside by the processing device, when the number of damaging pressure requests is greater than or equal to a first predefined alert threshold 15 or when the number of press requests ion of a damaging nature, accumulated over several flights, is greater than or equal to a second predefined alert threshold or when a slope in the number of damaging pressure stresses, accumulated over several flights, compared to a number of flights of the predetermined aircraft is greater than or equal to a third predefined alert threshold.

According to one embodiment of the invention, which can be provided for the monitoring device and / or for the monitoring method, the hydraulic equipment comprises a heat exchanger, forming part of a hydraulic circuit for the circulation of a hydraulic fluid of a turbomachine, the hydraulic circuit being positioned in the secondary gas flow of the turbomachine located between a nacelle and a casing of the turbomachine to cool the hydraulic fluid.

According to one embodiment of the invention, which can be provided for the monitoring device and / or for the monitoring method, the determined damage threshold is greater than or equal to 15% of a maximum and nominal hydraulic pressure of hydraulic equipment and is less than or equal to 35 c1i, of the hydraulic pressure, maximum and nominal.

5 The invention will be better understood on reading the description which will follow, given solely by way of nonlimiting example with reference to the appended drawings, in which: FIG. 1 diagrammatically represents a view in longitudinal section of a 5 example of a turbojet, on which there is the equipment which can be subjected to the device and to the monitoring method according to the invention, FIG. 2 diagrammatically represents an example of a hydraulic circuit for lubricating the turbojet of FIG. 1, comprising the equipment which can be subjected to the device and to the monitoring method according to the invention, FIG. 3 shows schematically a perspective view of an example of the equipment which can be subjected to the device and to the monitoring method according to the invention according to Figure 1, - Figure 4 is a diagram schematically showing an example of a damaging pressure load detectable by the dis positive and the monitoring method according to the invention, FIG. 5 is a diagram showing schematically an example of a pressure load which is not detected as being of a damaging nature by the device and the monitoring method according to invention, - figure 6 shows an example of a flowchart of the monitoring method according to the invention, - figure 7 shows schematically an example of the monitoring device according to the invention, - figure 8 schematically shows other equipment on which are carried out pressure measurements for the device and the monitoring method according to the invention, - figure 9 is a diagram showing schematically an example of a pressure cycle, in which data is missing, which can be detected by the monitoring device and method according to the invention, and FIG. 10 is a diagram schematically showing an example of a cycle of the pressure, which can be detected by the monitoring device and method according to the invention and in which missing data has been replaced according to an embodiment of the invention, FIG. 11 is a diagram schematically showing an example of numbers of pressure stresses on the ordinate, counted by the device and the monitoring method according to the invention as a function of the number of flights on the abscissa.

In FIGS. 1, 2 and 3, hydraulic equipment of an aircraft subjected to variations in hydraulic pressure in flight and to which the invention can be applied may for example comprise a heat exchanger 130, forming part of a circuit 10. hydraulic 100 for circulating a hydraulic fluid used for the in-flight operation of a turbomachine 10 or gas turbine engine assembly 10 of an aircraft such as for example an airplane.

The hydraulic circuit 100 is for example positioned in the bypass duct 40 of the secondary gas flow 52 of the turbomachine 10, located between a nacelle 42 and an external part 44 or casing 44 of the central engine 15 13 of the turbomachine 10, to cool the engine. hydraulic fluid, and is for example of annular shape.

This example of hydraulic equipment 130 is first described below in more detail with reference to FIGS. 1, 2 and 3.

In Figure 1, the gas turbine engine assembly 10 has a longitudinal axis 11.

The gas turbine engine assembly 10 includes a fan assembly 12 and a central gas turbine engine 13.

The central gas turbine engine 13 includes a high pressure compressor 14, a combustion chamber 16, and a high pressure turbine 18.

The gas turbine engine assembly 10 may also include a low pressure turbine 20.

The fan assembly 12 includes an array of fan blades 24 extending radially outward from a rotor disc 26.

The engine assembly 10 has an intake side 28 and an exhaust side 30.

The gas turbine engine assembly 10 also includes a plurality of bearing assemblies (not shown in the figures) used to provide rotary and axial support to the fan assembly 12, to the high pressure compressor 14, to the turbine. High pressure 18 and low pressure turbine 20, for example.

7 In operation, air flows through the blower assembly 12 and a first portion 50 (primary flow 50) of the air flow is routed through the high pressure compressor 14, in which the air flow is compressed and sent to the combustion chamber 16.

The hot combustion products (not shown in the figures) from the combustion chamber 16 are used to drive the turbines 18 and 20 and thereby produce the thrust of the gas turbine engine assembly 10.

The gas turbine engine assembly 10 also includes a bypass duct 40 which is used to pass a second portion 52 (bypass 52) of the air flow exhausted from the fan assembly 12 around the gas turbine engine. 10 central gas 13.

More precisely, the bypass duct 40 extends between an internal wall 201 of a fan fairing 42 or nacelle 42 and an external wall 203 of the separator 44 surrounding the central gas turbine engine 13.

Figure 2 is a simplified schematic illustration of an exemplary hydraulic circuit 100 for supplying lubricating hydraulic fluid, such as, for example, oil, which may be used in the gas turbine engine assembly 10. of figure 1.

In the exemplary embodiment, the system 100 includes an oil supply source 120, one or more pumps 110 and 112 which circulate the oil through bearings 104, 106, 108 of the central gas turbine engine 13 and into its gears 60 and return the hot oil through the heat exchanger 130 which cools the oil to a lower temperature.

Optionally, the heat exchanger 130 includes an inlet valve 132 and an outlet valve 134 and a bypass valve 136 which can be operated manually or electrically.

In the example shown in Figure 1, the heat exchanger 130 is an air-cooled heat exchanger which is positioned in the bypass duct 40.

The heat exchanger 130 is coupled to the interior wall 201 of the fan shroud 42 between the fan assembly 12 and a fan spacer 150.

In other embodiments not shown, the heat exchanger 130 may be coupled to the inner wall 201, upstream of the fan assembly 12 and downstream of the intake side 28.

As such, the heat exchanger 130 can be positioned anywhere along the axial length of the bypass duct 40 either on the inner side of the fan shroud 42 or on the outer wall 203 of the separator. 44.

In Figure 3, during assembly, the heat exchanger 130 is curved such that the heat exchanger assembly 130 has a circumferential and axial profile substantially similar to the circumferential and axial profile of at least one. part of the bypass duct 40, for example conforming to the circumferential and axial profile of the inner surface 201 of the fan shroud 42 as shown in FIG. 1 or the outer surface 203 of the separator 44 in other embodiments not shown.

As shown in Figure 3, heat exchanger 130 covers substantially the entire (about 320 °) circumference.

Alternatively, the heat exchanger 10 may be formed of several segments, which are fitted end to end to cover the same circumferential length.

In Figure 3, the heat exchanger 130 includes a manifold portion 202 extending between a first end 210 and an opposite second end 212.

The manifold portion 202 also includes a radially inner surface 220, a radially outer surface 222, such that the manifold portion 202 has a profile of substantially rectangular axial cross-section.

The manifold portion 202 also includes a plurality of cooling fins 230 extending radially inward from the interior surface 220 in the case of Figure 1, to face the bypass 52.

Of course, the fins 230 may be located on the outer surface 222, for example in embodiments where the heat exchanger 130 is mounted on the outer surface 203 of the separator 44 or on the outer surface of the fan shroud 42.

Of course, the fins 230 can be located both on the exterior surface 222 and on the interior surface 220.

The manifold portion 202 also contains at least one hydraulic fluid passage channel extending into the manifold portion 202 between its ends 210 and 212.

This hydraulic fluid passage channel is connected to at least one hydraulic fluid inlet connection 240, which is located at the end 210 and which is coupled downstream of the valve 132 (shown in FIG. 2) and at least a hydraulic fluid outlet connection 242, which is located at the end 212 and which is coupled upstream of the valve 134 (shown in Figure 2), so that the 9 valves 132 and 134 can be actuated to circulating the lubricating fluid of the system 100 through the channel of the heat exchanger 130.

The hydraulic fluid circulating in the heat exchanger 130 transfers part of its heat to the part 202 of the collector surrounding the channel, this part 202 of the collector 5 relinquishing through the fins 230 part of the heat received to the secondary flow air passing through the bypass duct 40 or air passing outside the fairing 42.

Embodiments of the device 400 for monitoring the life of hydraulic equipment according to the invention and of the method for monitoring the life of the hydraulic equipment are first described below with reference to FIGS. 4 to 10. hydraulic equipment according to the invention, having the steps mentioned below.

Of course, the device 400 for monitoring the life of the hydraulic equipment according to the invention and the method for monitoring the life of the hydraulic equipment according to the invention can be applied to any hydraulic equipment of the invention. an aircraft subjected in flight to variations in hydraulic pressure, this equipment possibly being different from the heat exchanger 130 described above and being generally referred to below as hydraulic equipment 130.

As illustrated in FIGS. 6 and 7, the device 400 for monitoring the life of the hydraulic equipment according to the invention and the method for monitoring the life of the hydraulic equipment according to the invention are intended for process measurement data 403, which were acquired during a flight on the aircraft and which are representative of the hydraulic pressure P (for example in the example described above in FIGS. 1 to 3, the pressure P of the internal oil of the hydraulic equipment 130) of the hydraulic equipment 130 as a function of the time t during this flight, to process these data 403 on the ground after the flight.

The device 400 thus comprises a reception interface 401 for receiving the measurement data 403 (or input data), during a first reception step E1.

Device 400 is configured to implement the method of monitoring the life of hydraulic equipment.

The device 400 comprises a processing device 402 connected to the reception interface 401.

The device 400 and the lifetime monitoring method are implemented by automatic means.

The processing device 402 and the means described can be implemented by a processor or a computer or a computer or a server, which are provided with computer processing programs for carrying out the processing described below and with permanent memories for. record the measurement data 403 and the processing operations carried out, the interface 401 possibly being an access port thereof.

The processing device 402 comprises a detector 404 for detecting, on the basis of the measurement data 403 during a second detection step E2 subsequent to the first reception step H, a SOLLEND pressure P stress of a damaging nature, called hereinafter SOLLEND stress in damaging pressure.

As illustrated in FIG. 4 showing on the ordinate a curve of pressure P as a function of time t on the abscissa, the SOLLEND stress in pressure P of damaging nature is detected by the fact that the pressure P includes an increase in pressure APALU. , greater than a determined threshold SAP of damage, this increase APALJG of pressure being followed by a decrease APDAI of pressure greater than the determined threshold SAE of damage.

The determined damage threshold SAp is a fatigue threshold of the hydraulic equipment 130 and has been determined beforehand.

The determined SAP threshold of damage is positive and not zero.

The pressure increase APAUG and the pressure decrease APDliq are each taken as an absolute value.

A cycle CYC of pressure P of the hydraulic equipment 130 in flight 25 begins at a certain start time T1 with a first prescribed pressure value P1 and ends at a certain end time T2 with a second prescribed pressure value P2.

The CYC cycle of pressure P can include none, one or more SOLLEND stresses in pressure P of a damaging nature, after having taken the first prescribed value P1 of the start of cycle pressure and before taking the second prescribed value P2 of the end pressure. cycle after the first prescribed pressure value Pl.

For example, in FIG. 4, three 11 SOLLEND stresses in pressure P of a damaging nature, represented by stars, are detected.

In FIG. 4, the maximum of the pressure P separating the increase APAuG from the decrease APDEG is represented by a star.

The processing device 402 comprises a counter 405 for counting during a third counting step E3 the number MENT of SOLLEND stresses in pressure P of a damaging nature in successive measurement data 403, for example in each CYC cycle of pressure or in each flight.

FIG. 5 illustrates a case where, during the second detection step E2, the detector 404 does not detect any SOLLEND stress in pressure P of a damaging nature in the measurement data 403, because the increase APAUG in pressure is less than the determined threshold SAP of damage, this increase APAuu, of pressure being followed by a decrease APDAI of pressure also less than the determined threshold SAE of damage.

In this case, no SOLLEND pressure P solicitation of a damaging nature is counted by the counter 405 during the third counting step E3.

The device 400 and the method according to the invention thus provide an estimate of the mechanical wear undergone by the hydraulic equipment 130 during the flight corresponding to the measurement data 403, by quantifying the MEND number of SOLLEND stresses with strong variations. of pressure undergone by this hydraulic equipment 130 during its operation during this flight.

This makes it possible to anticipate damage to the HO hydraulic equipment by monitoring the evolution of the MEND number of stresses flight after flight.

Thus, the number MEND of SOLLEND stresses in pressure P of a damaging nature is associated with the flight of the aircraft during which the measurement data 403 and / or 408 were acquired.

According to one embodiment of the invention, the determined SAE damage threshold is greater than or equal to 15 (> 4. Of a maximum and nominal hydraulic pressure PmAN of the hydraulic equipment and is less than or equal to 35% of the hydraulic, maximum and nominal pressure PGAx.

The determined SAP threshold 30 of damage can in particular be greater than or equal to 20% of PM and less than or equal to 30% of PME.

For example, the determined SAE damage threshold 12 may be equal to substantially 25% of P \ IAN.

The determined damage threshold Sm, the first prescribed pressure value Pl and the second prescribed pressure value P2 are part of the configuration parameters of the process and of the device 400.

5 According to one embodiment of the invention, the determined threshold SAp of damage, the first predefined alert threshold SALI, the second SAT threshold, 'predefined alert and the third pre-defined SAS threshold' form part of the configuration parameters of the method and of the device 400 and are prerecorded in a memory of the processing device 402.

The number MEND of solicitations 10 SOLLENu in pressure P of damaging nature, having been calculated, and / or the cumulative number MEND-ctmut of number MEND of solicitations in SOLLENu in pressure P of a damaging nature successive on several flights is recorded in a memory of the device 402 processing, which is updated on each run.

The processing device 402 may include an output interface 406 (which may be a display screen or the like) for supplying to the outside, during a step E7 output subsequent to step E3 or E6, as data of output the MEND number of SOLLEND stresses in pressure P of a damaging nature, having been counted by the counter 405 and / or the cumulative number IMEND-cumin of MEND number of SOLLENu stresses in pressure P of a damaging nature over 20 several flights and / or the first alert ALt message described below and / or the second alert AL2 message described below and / or the third alert AL3 message described below and possibly other indicators, such as the threshold Sm, determined for damage, the first prescribed value Pl of pressure and the second prescribed value P2 of pressure.

According to one embodiment of the invention, these configuration parameters are predefined as a function of the materials of the hydraulic equipment 130 and of its structure.

These configuration parameters can be set for the same type of hydraulic equipment 130 and / or for the same type of aircraft 30 According to one embodiment of the invention, the determined threshold Sm of damage can be variable during the life of the equipment 130.

According to one embodiment of the invention, the first prescribed pressure value P1 and the second prescribed pressure value P2 are substantially zero.

The first prescribed pressure value Pl of pressure may correspond to a pressure value of the hydraulic equipment 130 when the turbojet engine is stopped at the start of flight or at idle speed of the turbojet shortly after the start of the flight, in which case the first prescribed value Pl pressure is not zero.

The second prescribed pressure value P2 may correspond to a pressure value of the hydraulic equipment 130 when the turbojet engine is stopped at the end of the flight or at idle speed of the turbojet engine shortly before the end of the flight, in which case the second prescribed value P2 of pressure is not zero.

According to one embodiment of the invention, shown in Figures 7 and 8, the hydraulic equipment 130 may not be provided with a pressure sensor to measure its hydraulic pressure P.

In this case, the processing device 402 comprises an estimator 407 for determining, during an estimation step E4 subsequent to the reception step E1 and prior to the detection step E2, the hydraulic pressure P of the equipment 130 from the values 408 of another hydraulic pressure of another equipment 131 of the aircraft as a function of time t, which are included in the measurement data 403 and which were measured by a sensor 133 of measure provided for on this other equipment.

This other equipment 131 20 can for example form part of the same hydraulic circuit 100 as the hydraulic equipment 100 of FIG. 2, the sensor 133 making it possible for example to measure the internal oil pressure of the central engine 13 of the turbomachine 10 and being provided on this engine 13.

The estimator 407 may include a prerecorded hydraulic model or a prerecorded function for calculating or predicting the hydraulic pressure P of the equipment 130 from the values 408 of the other hydraulic pressure of the other equipment 131.

This has the advantage of having no impact on the design, weight, performance or cost of the hydraulic equipment.

In another embodiment of the invention not shown, a hydraulic equipment 130 is provided with a measuring sensor making it possible to directly measure the hydraulic pressure P of the hydraulic equipment 130.

14 Pressure P3 values may be missing between present pressure values which are temporally spaced.

For example, as shown in FIG. 9 during a pressure CYC cycle, pressure values P3 may be missing between the start time T 1 corresponding to the first prescribed pressure value PI and a pressure P present after P1 (or in another case not shown between a pressure P present prior to the second prescribed pressure value P2 and the end instant T2 corresponding to the second prescribed pressure value P2).

According to one embodiment of the invention, during a step 10 E5 of verifying the data using the detector 404 of the processing device 402, replacement pressure values P4, varying by one. linear manner, for example in the form of a single straight line, between these present pressure values P, P1 or P2, for example between the start time Ti corresponding to the first prescribed pressure value P1 and the present pressure P, as illustrated in Fig. 10 (or in the other above-mentioned case, the processing device 402 inserts replacement pressure values P4, varying in a linear fashion, for example in the form of a only straight line, between the pressure P present and the end instant corresponding to the second prescribed pressure value).

According to one embodiment of the invention, the method comprises, between the receiving step E1 and the step E2 or E4, the step E5 of verifying the data 403 or 408, for example to detect invalid data, to detect data. missing data and apply missing data replacement methods, as described above with reference to Figures 9 and 10.

The data 403, 408 may include in addition to the measurements of pressure P and measurements of time t, the serial number of the engine, the number of flights counted by another counter of the turbojet engine, a serial number of the hydraulic equipment. monitoring, a history of pressure measurements P.

According to one embodiment of the invention, the method comprises, after the counting step E3, a step E6 for updating the cumulative counter 405, during which the number NIErD of SOLLEND stresses in pressure P of a damaging nature is added. successive, having been counted on the flight in the measurement data 403 received at a previous cumulative value of counter 405, established for previous flights and having been previously recorded in memory, to obtain a new cumulative value of counter 405, c 'That is to say a cumulative number MEND-CUMUL of solicitations SOLLEND in pressure P with character 5 successive damage on several flights, which is re-recorded in the memory.

According to one embodiment of the invention, the processing device 402 comprises a first alert means 409 for transmitting to the outside, during a warning step E8 subsequent to the counting step E3, a first alert message AL1, when the number MEN-D of SOLLEND pressure P solicitations of damaging nature is greater than or equal to a first predefined alert threshold SALI, as shown in FIG. 7.

According to one embodiment of the invention, the processing device 402 comprises a second alert means 410 for transmitting to the outside, during a warning step E8 subsequent to the counting step E3, a second alert AL2 message 15, when the number MEND-CUMUL of SOLLEND requests in pressure P of a damaging nature, accumulated over several flights, is greater than or equal to a second predefined alert threshold SAL2, as shown in figure 7.

According to one embodiment of the invention, the processing device 402 comprises a third alert means 411 for transmitting to the outside, during a warning step E8 subsequent to the counting step E3, a third alert message AL3, when an AMEND / ANvoL slope of the MEND-cuma number of solicitations SOLLFND in pressure P of a damaging nature, accumulated over several flights, compared to a number Nu ", of flights of the predetermined aircraft is greater than or equal to a third predefined alert threshold SAL3, as shown in FIGS. 7 and 11.

FIG. 11 illustrates several examples of curves C1, C2, C3, C4, C5 of MEND-cumur numbers of SOLLEND stresses in pressure P of a damaging nature, accumulated over several flights, as a function of the number NvoL of flights for respectively several engines 10 in operating on multiple aircraft.

The curves C1, C3, C4, C5 have a linear behavior during flights.

30 The C2 curve shows a C20 break with an increase C22 in the AMEND / ANvoL slope after this C20 break, which is explained by changes in the operation of the engine and may represent the beginnings of a premature degradation of the engine. hydraulic equipment 130, because the MEND number per flight becomes greater than that observed at the start of C21 of life.

According to one embodiment of the invention, the method comprises a step 5 of calculating a confidence indicator of the number MENT, of pressure stresses of a damaging nature having been counted.

This confidence indicator can be calculated as being a numerical value weighted by the quality of the data 403 and / or 408, estimated during step E2 and by the number of missing data.

Of course, the above embodiments, characteristics, possibilities and examples can be combined with each other or be selected independently of each other.

Claims (11)

CLAIMS 1. Device (400) for monitoring the life of at least one hydraulic item of equipment (130) of an aircraft subjected to variations in hydraulic pressure (P) in flight, the device (400) comprising a reception interface (401) of measurement data (403, 408) representative of the hydraulic pressure (P) of the equipment (130) as a function of time (t) in flight, characterized in that the device (400) comprises a device (402) for processing, comprising means (404) for detecting, from the measurement data (403, 408), a stress (SOLLEND) in pressure (P) of a damaging nature, defined by the fact that the pressure (P) includes an increase (AP, Auci) of pressure, greater than a determined threshold (Sn p) p) of damage greater than zero, followed by a decrease (APDD4) of pressure greater than the determined threshold (SA) of damage, and a means (405) counting to count the number (MEN-D) of stresses (SOLLEND) in pressure (P) of a damaging nature. 2. Device according to claim 1, characterized in that it comprises an estimator (407) for determining the hydraulic pressure (P) of the equipment from values of another hydraulic pressure of another equipment (131) of the aircraft as a function of time (t), which are included in the measurement data (408) and which have been measured by a measurement sensor (133) provided on this other equipment (131). 3. Device according to any one of claims 1 and 2, characterized in that the hydraulic equipment comprises a heat exchanger (130), forming part of a hydraulic circuit (100) for circulating a hydraulic fluid from a turbomachine (10), the hydraulic circuit (100) being positioned in the secondary gas flow (52) of the turbomachine located between a nacelle (42) and a casing (44) of the turbomachine (10) for cooling the hydraulic fluid. 4. Device according to any one of claims 1 to 3, characterized in 3 0 that the determined threshold (SA) of damage is greater than or equal to 15% of a hydraulic pressure, maximum and nominal (P x) of the hydraulic equipment 18 and is less than or equal to 35 of the hydraulic pressure, maximum and nominal (PmAx). 5. Device according to any one of claims 1 to 4, characterized in that the processing device (402) comprises an alert means for transmitting an alert message (ALI, AL2, AL3) to the outside. , when the number (MET)) of stresses (SOLLEND) in pressure (P) of a damaging nature is greater than or equal to a first predefined alert threshold (SALI) or when the number (M, UMM) of stresses (SOLLE1, -D) in pressure (P) of a damaging nature, accumulated over several flights, is greater than or equal to a second threshold (predefined warning SAO or 10 when a slope (AMENDLANvoL) of the number (MES-cumut) of requests ( SOLLEND) in pressure (P) of a damaging nature, accumulated over several flights, relative to a number (N \ 01) of flights of the predetermined aircraft is greater than or equal to a third predefined alert threshold (SA ,;) . 6. A method of monitoring the life of at least one hydraulic equipment (130) of an aircraft subjected to variations in hydraulic pressure (P) in flight, a method in which one receives, during a step ( El) for receiving on an interface (401) for receiving, measurement data (403, 408) representative of the hydraulic pressure (P) of the equipment (130) as a function of time (t) in flight, characterized in that 20 during a detection step (E2), a processing device (402), from the measurement data (403, 408), is detected by a pressure (P) solicitation (SOLLEND) damaging character, defined by the fact that the pressure (P) includes an increase (APAucT) in pressure, greater than a determined threshold (SAp) of damage greater than zero, followed by a decrease (APnim) 25 in pressure greater than determined threshold (SAp) of damage, during a counting step (E3), the processing device (402) counts the number (MEND) d e stresses (SOLLEND) in pressure (P) of a damaging nature. 7. Method according to claim 6, characterized in that in the event of missing pressure values (P3) between present pressure values (PI, P2, P) which are spaced apart in time, values of replacement pressure (P4) varying in a linear fashion between these present pressure values (P1, P2, P). 8. A method according to claim 6 or 7, characterized in that the measurement data (408) comprises values of another hydraulic pressure of other equipment (131) of the aircraft as a function of time (t). , having been measured by a measurement sensor (133) provided on this other equipment (131) before the reception step (E1), the method comprising an estimation step (E4), which is subsequent to the step ( E1) reception and prior to the detection step (E2) and during which an estimator (407) of the treatment device (402) is estimated, the hydraulic pressure (P) of the equipment from the values of the other hydraulic pressure of the other equipment (131) of the aircraft 9. A method according to any one of claims 6 to 8, characterized in that the hydraulic equipment comprises a heat exchanger (130), forming part of a hydraulic circuit (100) for circulating a hydraulic fluid. 'a turbomachine (10), the hydraulic circuit (100) being positioned in the secondary gas flow (52) of the turbomachine located between a nacelle (42) and a casing (44) of the turbomachine (10) for cooling the hydraulic fluid . 10. A method according to any one of claims 6 to 9, characterized in that the determined threshold (SAF) of damage is greater than or equal to 15% of a hydraulic pressure, maximum and nominal (PmAx) of the. hydraulic equipment and is less than or equal to 35% of the hydraulic pressure, maximum and nominal (PMAX). 11. Method according to any one of claims 6 to 10, characterized in that during a step (E8) of warning subsequent to the counting step (E3), the transmission is sent to the. external by the device (402) for processing an alert message (ALI, AL2, AL3), when the number (MEND) of solicitations (SOLLEND) under pressure (P) of a damaging nature and greater than or equal to a first threshold ( SALI) predefined alert or when the number (MEND-CUMUL) of damaging pressure (P) solicitations (SOLLEND), accumulated over several flights, is greater than or equal to a second predefined alert threshold (SAL2) or when a slope 20 (AMEND / ANvo () of the number (M END of stresses (SOLLEND) in pressure (P) of a damaging nature, accumulated over several flights, compared to a number (NN-0L) of flights of the predetermined aircraft is greater than or equal to a third predefined alert threshold (SAL3).