A method for assisting with the management of at least one cumulative aging process.

Abstract

The invention relates to a method for piloting assistance for an operator, for example a pilot, or for an automated system, for example an autopilot, said assistance relating to at least one cumulative aging (CV), for example creep, of at least a part of a gas turbine of an aircraft during a mission of said aircraft, said method comprising a step of determining an aging progression score which is a function of a plurality of terms comprising TERM 1, TERM 2, TERM 3, TERM 4 and TERM 5, said method comprising a step of providing information on said at least one cumulative aging to the operator or the automated system for said piloting assistance, according to said aging progression score. Abstract figure: [Fig. 2]

Description

Title of the invention: A method for assisting control in managing at least one cumulative aging process Technical field of the invention

[0001] The invention relates to a method of piloting assistance for an operator, for example a pilot, or for an automated system, for example an autopilot, enabling the management, flight after flight, of at least one cumulative aging, for example the finning, of at least a part of a gas turbine of an aircraft, for example a helicopter, in order to make the best use of it in the long term. Prior art

[0002] An aircraft pilot generally has access to piloting instructions relating to propulsion systems, displayed in the cockpit. These instructions notably refer to certified limits (maximum limits not to be exceeded, limits required in the flight manual), these limits being managed by the pilot or managed by the computer.

[0003] Such limits include, for example, the NI (rotational speed of the gas generator at the high-pressure shaft), the T45H conformed temperature of the high-pressure turbine, the torque of the power shaft, or an indicator combining this information. These limits constitute, for example, thresholds that must not be exceeded in stabilized flight, and for which maximum continuous operating times can be defined by regulation.

[0004] These indications do not take into account mission-specific objectives, such as a quota, or a notion of acceptable cumulative aging. They are purely instantaneous and are not intended to prevent cumulative aging patterns from leading to a need for premature refurbishment of the turbomachine, for example before its scheduled overhaul.

[0005] In a context of relatively constant and predictable usage, such as airliner missions, predictive methods exist that establish binary indices for throttle position, correctly corresponding to maintenance costs. These predictive methods also most often incorporate maintenance costs and fuel consumption costs.

[0006] For versatile applications, such as the varied missions of helicopters, the correlation of a binary setpoint (whether torque, gas generator speed, or temperature) with costs is not reliable. Currently, in this context, only ground-based monitoring of meters exists, particularly with regard to fine-tuning, which is carried out manually or with tools.

[0007] However, in this context, with regard to these complex cumulative aging processes, such a posteriori monitoring provides no useful prospective indication for subsequent flights and is not currently capable of helping the pilot to meet a cumulative target during the flight, for example a target given by a fleet manager.

[0008] Such monitoring or guidance also does not provide information that would allow the pilot to understand and develop an intuition about the actions to be taken to manage aging processes. Indeed, these aging phenomena are multifactorial and non-linear. Consequently, a pilot cannot develop a reliable intuition about the conditions under which these aging processes accelerate or slow down without additional guidance.

[0009] Cumulative aging is a form of damage that increases over time. Such aging corresponds perfectly to the phenomenon of turbine blade wear, within the context of the intended application, but can also be oxidation, corrosion, or mechanical wear of parts (friction wear or bearing wear, for example).

[0010] Other types of aging can also occur, such as predominantly "cyclic" aging modes, related to a number of times stress thresholds are crossed, both upwards and downwards (low-cycle fatigue (LCF), thermal cycling, number of start / stop cycles, etc.). However, it is difficult to influence such cyclic aging. Presentation of the invention

[0011] This document aims to remedy the aforementioned drawbacks.

[0012] To this end, the present document proposes a piloting assistance method for an operator, for example a pilot, or for an automated system, for example an autopilot, said assistance relating to at least one cumulative aging, for example the finning, of at least a part of a gas turbine of an aircraft during a mission of said aircraft, said method comprising a step of determining an aging progression score which is a function of a plurality of terms comprising TERM1, TERM2, TERM3, TERM4 and TERM5,

[0013] and we define for the calculation of the aging progression score: the mission quota, Q = ,

[0014] where - QFactor is a factor, for example between 0.1 and 10, which should be modifiable by the operator if possible; QFactorageing is a factor; DQdbie, QFactoring = - SD is a major maintenance trigger threshold for a meter Cumulative aging (CV), in hours DQ j is the target service life of said part of the gas turbine, in hours, over the life of the engine before major maintenance or minimum power margin is reached, DQ is the service life between two overhauls of said part of the gas turbine, in flight hours, preferably a target service life for the current flight, assuming that all flights are conducted with the same power margin, DQ = DQmin + ÇEPCTifj^ yx (DQtarget — DQmin) — (ePCT4mo(f) x (DQmax — DQmin) EPCT4Mny x [(FPCr4„ J2 - EPCT4^ x ËPCT4Moy] x EP Ct^. + [EPCT4Moy DQmin) EPCT4>, x [(EPC™,.} — EPCrt., x epcT4„ ] {_ ^Avg [V 1 l^New J^AvgJ X (EPCTi)2

[0015] - the default quota of the mission, "sd, ^Fe

[0016] - a measure of the current power margin of the motor, EPCT4, for example between 0 and 10,

[0017] - a margin of verification of the estimated power of a new engine, EPCT4New, by example equal to 10,

[0018] - an average margin for verifying the power of a new engine,

[0019] EPCT4Moy = X* EPCT4New,

[0020] - a coefficient X, X preferably being equal to 1 / 3,

[0021] - a minimum duration, DQmin, of the major maintenance trigger threshold for the engine, for example if it were to operate for its entire lifespan without any power margin, such as EPCT4 = 0,

[0022] - a maximum duration, DQmax, of the major maintenance trigger threshold for the engine, for example if it were to operate its entire life with the maximum power margin, such as EPCT4MOy = EPCT4\ew for example DQmax= DQcible *3,

[0023] - the cumulative aging counter CV which is a value proportional to the cumulative aging, the mission's estimated flight time in hours, M, for example between 0.2 and 3 hours, - the default estimated flight time of the mission in hours, ^def, for example on the order of 1 hour, - the cumulative flight time of the mission, in hours, at a time t of the mission, T(t) - a first SI threshold, for example between 0.3 and 0.8, for example equal to 0.5, - a second threshold S2, for example between 3 and 10, for example equal to 5, - the start of the mission defined by the instant t= tO of the start of flight, - a time t= tl at the end of a so-called start-of-mission phase, also defined such that:

[0024] — tl - tO is greater than a duration between 1 and 15 minutes, and / or

[0025] — tl is the first instant t greater than t0 for which the flight speed of the aircraft is greater than a predetermined speed, for example 40 knots for a helicopter, and / or

[0026] — tl is the first instant t greater than t0 for which the aircraft's altitude by ground clearance, also called ground ratio, is greater than a predetermined value, for example 500 feet, - a sliding duration X in seconds, for example between 10 and 30 seconds, for example on the order of 20 seconds, - the average gradient sliding over X seconds, _ _ cv (t) - cv(tx), (t) ~ Qm - the cumulative flight hours since the start of the mission (tO), at a given time t of the mission without information on the planned mission flight duration M, CV(t) - cv(tO)' B(t) = QT(t) - the cumulative flight hours since the start of the mission, at a given time t during the mission, anticipating a flight duration of "usual short missions" of Y, in hours, Y being a parameter to be adapted to the application context, chosen between MDEr / 2 and cy _ cy C(t) =--—-----:—— Q*max(Y,T(t)) - the cumulative flight hours since the start of the mission, at a given moment t of the mission anticipating the projected mission duration M, 5(0 = CV(t) - CV(tO) Q *M

[0027] TERM 1 => S2, ' (otherwise, 0') f 2, if t > tl and M = MDEF and Q = QDEF and D(t) > (T(t) / M), TERM2 = |sûîonl, if t > tl and if the trend of B(t) over X seconds is monotonically increasing, 1 otherwise, 0 _ | 2, if t > tl and M — MDEF and Q — QDEF and C(t) > 1, , TERM 3 = j otherwise l, if t > tl and (M * MDEF or Q QDEF) and C(t) > 1, '■ otherwise, 0

[0028] - (1, if t > tl and (M * MDEF or Q ≠ QDEF) and D(t) > (Tft) / M) ' and X JS I 1 'XI t smon, 0 SCORE -

[0029] - r _ (Lsi t > tl et (M #= MDEF ou Q #= QDEF ) etD(t) > 1 , ic nM b — ) . _ (smon, O

[0030] said method comprising a step of providing information of said at least one cumulative aging to the operator or to the automated system for said piloting assistance, according to said aging progression score.

[0031] The aging progression score can be defined as follows: Q, if ?l(t) < IF TERM1 + TERM2 + TERM3 + TERM4 + TERM5, otherwise

[0032] The step of providing said information to an operator can be carried out by display.

[0033] As previously stated, the cumulative aging of a part of a gas turbine is the damage to the part concerned that increases over time. Such aging is primarily the phenomenon of aging, but can also be oxidation, corrosion, or mechanical wear of the components of the part concerned.

[0034] The cumulative aging counter CV is a value generally provided by the gas turbine's computer and is proportional to the cumulative aging, measured or determined by calculation, from values ​​obtained from sensors (gas generator rotational speed, temperature within the gas turbine, torque, ambient temperature, deformations, etc.). The higher the CV value, the greater the cumulative aging of the parts in the relevant section or module of the gas turbine.

[0035] An aircraft mission is defined by a succession of flight phases between a start and an end of the mission. Typically, such a mission may include one or more takeoff and landing phases, and flight phases at varying speeds.

[0036] The major maintenance trigger threshold is a predetermined threshold, set by the gas turbine manufacturer, beyond which a major maintenance operation, known as major maintenance, is necessary to ensure the proper functioning of the gas turbine or to prevent its premature damage. Such an operation generally requires the removal of the gas turbine.

[0037] DQ is defined as a second-degree function of the verification margin

[0038] of the motor's current power, EPCT4. In this way, one can choose between: - Aircraft performance taking advantage of the engine's best performance on each flight, in which case it is the achievable performance (beyond what is guaranteed) that varies significantly depending on the engine's margins. In the limiting case, DQmin = DQmax = DQtarget, and - More consistent aircraft performance over engine life, while maintaining the same overall service life target. This can for example be achieved by choosing DQmin = DQcible / 5 and DQmax = DQcible *3.

[0039] DQ therefore takes into account the engine's lifespan and produces a compensation, called

[0040] Engine margin compensation: - at the beginning of the engine's life, compensation leads to targeting a lower quota than the average target quota, - in the middle of the engine's life, that is, when the engine has reached an intermediate margin value corresponding to the average potential (for example, an output shaft power Pw such that it is equal to 2 / 3 of the certified limits and a constant high-pressure turbine conformal temperature value T45H), the compensation is zero, - At the end of the engine's life (i.e. in the last period of the engine's potential), that is, for lower margin values, compensation leads to targeting a higher quota than the average target quota in order to continue to achieve superior aircraft performance.

[0041] The magnitude of this compensation with respect to the engine's lifespan (the difference between the compensation at the beginning of the engine's life and the compensation at the end of the engine's life) is adjusted according to:

[0042] - on the one hand, the acceptability of an operational constraint at the beginning of the engine's life while the visible damage will be less than a linear progression, and

[0043] - on the other hand, the desired engine operating proportion. For a function In linear operation, there will be no compensation, and for non-linear operation, there will be strong compensation leading to more constant aircraft performance.

[0044] The flight time between two general overhauls is known by the abbreviation TBO for "Time Between Overhauls", in English.

[0045] The estimated flight time of the mission, specified as M, is a value determined before the start of the mission and entered into an aircraft computer, for example via an interface. This time can be entered by an operator, for example a pilot.

[0046] The estimated flight time, whether default or not, of the mission specified M or M dEF is, for example, between 0.2 and 3 hours. MDEF is, for example, on the order of 1.5 hours.

[0047] M will be populated with the collection value of MDEF if M is not populated by the operator.

[0048] The flight duration of typical short missions Y will either be fixed for a given application, for example on the order of 0.8 hours if MDEF = 1.5h, or completed by the application and calculated as an average of the flight durations of previous aircraft missions less than MDEF in the interval, from MDEF / 2 to

[0049] The parameter Y can be adapted for example within this range depending on whether there are more or fewer mission frequencies much shorter than MDEF.

[0050] The cumulative flight time of the mission at a time t, T(t) is the time elapsed between the start of the mission t0 and time t.

[0051] The CV value sliding over X seconds at a time t is equal to the difference between the CV values ​​at time t and CV at time tX.

[0052] The calculation of all or part of said terms can be carried out in real time, at time periods of less than 1 second for example, on the order of 500ms for example.

[0053] Inhibiting the calculations of TERM2, TERM3, TERM4 and TERM5, i.e. setting these terms to 0, during the start phase of the mission (T(t) < tl), makes it possible not to hinder the operator, for example the pilot, by the appearance of indications during the most delicate flight phases (takeoff, etc.).

[0054] Each term serves a different purpose and therefore allows them to be combined.

[0055] When the engine stress level at time t leads to aging If the minor (SI to be defined by the engine manufacturer) condition is met, the score is reset to zero, regardless of the value of the individual terms. Indeed, there is no point in providing information, for example via display, if engine usage no longer significantly affects the final total; there is no need to continue encouraging reduced usage. This avoids unnecessarily limiting operational solutions, since exceeding the quota carries no risk and subsequent missions always offer opportunities for compensation.

[0056] The current engine power verification margin, EPCT4, the estimated power verification margin of a new engine, EPCT4New, and the average power verification margin of an engine whose hot parts are at mid-life, EPCT4Moy, are a picture of the additional power margin that an engine can give over its conformed temperature limit T45H, compared to the certified guaranteed minimum.

[0057] The first term, TERM 1, signals to the operator a very high stress, with no obvious correlation to the acceptable operating limits. It is an initial indication to the operator that current flight conditions may lead to significant cumulative aging, and it can be displayed from the very beginning of the flight. It also provides regular feedback that enhances the operator's intuitive understanding of the situation.

[0058] The second term TERM 2 allows the score to be reinforced if the level of solicitation At time t, this leads to an increase in aging that is not offset by an increase in mission flight duration, versus the quota Q, or that exceeds a linear progression (if the values ​​M and Q are not defined by the operator). This indicator strengthens the score when, particularly at the beginning of the mission, the demand is high. It is an intermediate variant between the gradient and the cumulative aging, incorporating any previous debits and credits, and allows for reporting in the first part of the mission. It gradually loses relevance as the mission lengthens and subsequently no longer contributes to the score, unless the demand remains truly excessive.

[0059] Instead of assigning a weight of 2 to TERM 2 (“option 1”) in the case where no effort is made to customize the objective of future missions (i.e., when neither the quota Q nor the mission flight duration M has been defined, for example by the operator), the weight may remain at 1, which leads to a maximum score of less than 5 (“option 2”).

[0060] The third term, TERM 3, allows the score to be increased if the quota is exceeded, assuming the mission lasts Y hours, and to be decreased if, after exceeding the flight time Y, the cumulative total has converged again below the quota. This term provides an initial level of score progression in absolute terms of the cumulative hours, preventing an untimely increase in the score at the beginning of the mission if the minimum duration of Y hours was not used (which is why B(t) is not used in absolute terms).

[0061] Such a method can also provide piloting assistance and / or training for the operator on critical conditions leading to an aggravation of said cumulative aging.

[0062] Instead of assigning a weight of 2 to TERM 3 (“option 1”), in the case where no effort is made to customize the objective of future missions (i.e., when neither the quota Q nor the mission flight duration M has been defined, for example by the operator), the weight may remain at 1, which leads to a maximum score of less than 5 (“option 2”).

[0063] The terms TERM 4 and TERM 5 are inhibited (equal to 0) when no effort is made to customize the objective of future missions (i.e., when neither the quota Q nor the mission flight duration M has been defined, for example by the operator). These terms may also be inhibited for other reasons (desire for discreet displays and low usage, for example in a context of high mission variability).

[0064] The fourth term, TERM 4, allows the score to be increased if the cumulative score follows a progression greater than a linear progression towards the specified quota Q, for the specified mission flight duration M. As the beginning of the mission is generally more demanding,

[0074] - TERM 6 = This allows for early and precise reinforcement of vigilance, and indicates that moderation or action by the pilot is desirable.

[0065] The fifth term TERM 5 allows the score to be strengthened by comparison of the cumulative score to the quota Q, in particular in a case where it is not possible to stay within the quota during the mission, but it is still possible to limit the overrun.

[0066] It is also possible to freeze the score display during transitional flight phases when the pilot is occupied with other tasks. Such a phase can be determined, in particular, by a significant variation in the moving average (for example, over a defined period) of engine torque, outside a narrow range (for example, ±5%) around the moving average. This allows the display to be frozen during such maneuvers.

[0067] It is also possible to display an indicator, for example a green indicator, if A(t) < SI (or other value) in the display area of ​​the aircraft engine speed limits (first limit indicator, NI margin, T45H - defined above), this area being a priority attention area for the pilot.

[0068] Three states of vigilance can be permitted in the "option 2" case: - no vigilance: no indication of the score - moderate vigilance: M = Mdef, Q = Qdef, the maximum score then being equal to 3, in the case of "option 2". - high vigilance: invitation to fill in M ​​Mdef and M Mdef, the maximum score then being equal to 5.

[0069] Conversely, in the case "option 1", the scale of 5 is preferred and it is the fineness of the indication that is degraded with scores that evolve by 2 points at a time for TERM2 and TERM3.

[0070] It is also possible to manage the case of several cumulative aging processes (both aging and corrosion for example, which are two different cumulative aging processes).

[0071] For the calculation of the aging progression score, we can further define:

[0072] - a first component, _Comp_FBtime, for example equal to -0.1 per flight hour (or by "Flight Hours" in English),

[0073] - a second component, _Comp_FBageing, for example equal to -0, l / (EPCT4 / EPCT4New* 100), _Comp_FBtime + _Comp_FBaqeing x )] x [E - T(t)] '

[0075] the plurality of terms including further TERM 6.

[0076] The aging progression score can then be defined as follows: SCORE — f Si' [TERM1 + TERM2 + TERM3 + TERM4 + TERM5 + TERM6, otherwise

[0077] The sixth term, TERM 6, allows for the addition of a compensation to the score to account for aircraft weight reduction, referred to as weight reduction compensation. TERM 6 produces an average compensation for the score progression in such a way as to correct for the decrease in damage progression, under given flight conditions, due to aircraft weight reduction with an associated standard average fuel consumption, itself dependent on the engine power margin. The slope value of this weight reduction compensation is adjusted to avoid overcompensation.

[0078] TERM 6 is the product of a first compensation slope parameter [YT(tJ] and

[0079] of a second compensation slope parameter \_Comp_FBtime+ _Comp_FBageing * (EPCT4 / EPCT4New)].

[0080] The first compensation slope parameter [YT(tJ]] is dependent on mission time and zero for T(t) = Y. It is calculated to produce the average compensation for the score progression. In this way, it compensates for the decrease in damage progression at the desired standard average speed, due to the aircraft's weight reduction.

[0081] and its guaranteed average reference consumption.

[0082] The second compensation slope parameter [_Comp_FBrime+ _Comp_FBageing * (EPCT4 / EPCT4New)] has a component proportional to EPCT4. It is calculated to adjust the compensation slope on average for engines from a new to an aged state.

[0083] The compensation for weight reduction helps avoid a degree of conservatism at the beginning of a mission, which is avoidable. Operators can thus perform missions with less variation in achievable speeds throughout the mission. For example, this is particularly suitable for missions where the speed requirement is high at the start.

[0084] The calculated terms are relatively stable, but instabilities may exist. To mitigate such instabilities, hysteresis can be applied to the score display. Some terms may have a suitable hysteresis, for example, a higher hysteresis than other terms.

[0085] The aging progression score can be defined as follows: SCORE = TERM1 + TERM2 + TERM3 + TERM4 + TERM3 + TERM6'

[0086] The method may further include a step of determining an inverse aging progression score defined as follows: f 100, if SCORE < 1 Inverted SCORE = I 1 5 [AMX {0; MZN{1; (—- * SCORE + -)}} * 100, smon

[0087] said method further comprising a step of providing inverse information of said at least one cumulative aging to the operator or the automated system for said piloting assistance, according to said inverse aging progression score.

[0088] The aging progression score can, in some cases, be too demanding for the operator, as they must adjust the piloting to a median value. The inverse progression score allows the operator to adjust the piloting to 100% and assume that, even if they do not have the opportunity to check later, the overall objective will still be achieved. Conversely, this can limit visibility into opportunities to improve flight conditions in specific cases (for example, the deposition of a significant payload mid-mission).

[0089] Cumulative aging can be due to browning, and / or oxidation, and / or the corrosion.

[0090] Said method may be capable of providing information concerning at least two different cumulative agings, the individual score of each aging being determined and a general score being calculated on the basis of said individual scores, for example in the form of an average or a weighted average, the information of said at least one cumulative aging to be provided to the user being dependent on said general score.

[0091] It can be determined whether t is out of the start phase of the mission or not using a flight time elapsed since the start of the mission, and / or the flight speed of the aircraft, and / or the altitude of the aircraft relative to the ground.

[0092] The level or quantity of information of said at least one cumulative aging provided to the operator may vary depending on the aging progression score, and / or the value of A(t), and / or the flight phase concerned.

[0093] The level of information can in particular vary progressively by increment, for example by displaying a value between 0 and 5 or by displaying a progress bar, or even by not displaying such a value.

[0094] The amount of information can also vary by adding or removing information, so as to have more or less detailed information depending on the situation.

[0095] In particular, it is possible that no information will be provided (for example, no display) during certain critical flight phases, for example during the initial mission phase, or if aging is low (low score or A(t)). Increasingly complex information (different levels of information) may be provided or displayed according to flight phases, aging, or at the operator's request.

[0096] In general, the invention proposes to determine or calculate laws in real time and real-time tests on these laws, leading to indications (displayable or not in the cockpit, at different levels of detail or according to the phases of flight), regardless of the aircraft and the installation (single or multi-engine).

[0097] These indications are preferably not unnecessarily disruptive, particularly during flight phases that require the pilot's full attention. (For example, they will be displayed so as to be visible during long phases – cruise or climb flight (discreet flashing, for example) – and displayed continuously, without being intrusive, or even inhibited (no flashing, etc.) during phases with high power variation.)

[0098] These guidelines encourage and guide pilots to act during long, stable phases of flight, managing the cumulative aging of major propulsion system components flight after flight. As previously stated, these guidelines can be adjusted according to the score or previous cumulative aging, the types and business objectives of the missions, and the operational context.

[0099] These indications must be progressive (several levels of alert rather than a binary alert), such progressiveness being particularly useful when aging is not very predictable, when the short-term consequences are minor, when the use of the aircraft is versatile, and to provide the pilot with a perception of the flight conditions which produce cumulative aging (not intuitive without an indication or with a binary indication).

[0100] Such indications allowing the identification of phases which cause more or less pronounced cumulative aging can also contribute to more ecological management decisions (CO2 emissions, etc.).

[0101] Unlike existing applications in a non-versatile usage context, this score does not derive from an invariant cost calculation.

[0102] Here, the fleet manager, keen to get the most out of their gas turbines, can, by monitoring the trend retrospectively, modify the quota and the scoring guidelines to be followed by the pilot to allow for a generally controlled cumulative aging trajectory. They can do this by considering the full range of their priorities, the geographical context of operation, seasonality, engine age, air intake protection needs, and all other influencing factors, through a pragmatic method of learning and guidelines using the graduated scale of the invention.

[0103] On the other hand, a combination with fuel-efficient condition indicators is a logical association with this indicator, for example, adding a fuel economy score from 0 to 2 depending on the deviation from flight conditions the most economical stables.

[0104] This document may also relate to an aircraft comprising a display unit configured to provide information on at least one cumulative aging, said information being derived from a flight assistance method of the type described above.

[0105] The display unit may be an information bar.

[0106] The aircraft may be a rotary-wing aircraft, in particular a helicopter. Brief description of the figures

[0107] [Fig-1] is a trend diagram illustrating an evolution of the damage engine over its lifetime, this diagram represents the aircraft speed and the cumulative aging counter (CV) without engine margin compensation,

[0108] [Fig.2] is a trend diagram illustrating an evolution of the damage engine over the engine's lifetime, this diagram representing the aircraft speed and the cumulative aging counter CV with engine margin compensation according to one embodiment,

[0109] [Fig.3] is a trend diagram illustrating an evolution in the accumulation of Engine trim, this diagram representing the aircraft speed and the cumulative aging counter CV with engine margin compensation according to one embodiment,

[0110] [Fig.4] is a trend diagram illustrating an evolution over time of a mission, this diagram representing the aircraft speed and the aging progression score without weight compensation, in the case of a substantially constant aging progression score,

[0111] [Fig.5] is a trend diagram illustrating an evolution over time of a mission, this diagram representing the aircraft speed and the aging progression score without weight compensation, in the case of a substantially constant aircraft speed, and

[0112] [Fig.6] is a trend diagram illustrating an evolution over time of a mission, this diagram representing the aging progression score with compensation for lightening according to a mode of implementation. Detailed description of the invention

[0113] The diagram in [Fig. 1] represents the case for which DQ=DQciMe and therefore Q = QFactor * SD / DQcibie. In other words, DQ is a constant and corresponds to the target lifespan of that part of the gas turbine, without taking into account the engine's margin compensation. The aircraft speed in this example is V_aeronef_def and the cumulative aging counter is CV_def. By counter of Aging refers to cumulative damage.

[0114] The diagram in [Fig. 2] represents an embodiment in which DQ is a second-degree function of the engine's current power verification margin, EPCT4. The aircraft speed in this embodiment is V_aeronef and the cumulative aging counter is CV. In other words, this embodiment corresponds to the case where engine margin compensation is taken into account. Unlike CV_def in [Fig. 1], the cumulative aging counter CV does not follow a linear progression. It can be seen that taking into account the evolution of the engine margin (in the form of engine margin compensation illustrated in [Fig. 2]) makes it possible to maintain more constant aircraft performance (i.e., a more constant speed) over the engine's lifetime. The aircraft speed is higher at the end of the engine's life compared to the case without engine margin compensation in [Fig. 1].

[0115] The diagram in [Fig. 3] represents a specific embodiment of [Fig. 2] in which engine life is linked to the cumulative wear. In other words, it is the wear that triggers the overhaul criterion for the major components concerned. The aircraft speed in this particular example is V_aeronef_creep and the cumulative wear counter is CV_creep. Point P represents a limiting situation where CV_creep reaches a maximum value corresponding to a cumulative wear of 100%. At point P, the major components concerned must therefore be overhauled. In other examples, it is possible that the engine may have to be shut down based on other wear characteristics.

[0116] The diagram in [Fig. 4] represents the case of a substantially constant aging progression score (for example, under the action of a pilot making speed corrections for this purpose). The aging progression score, here SCORE_def_l, is substantially constant from point PL. It can be seen that for a substantially constant aging progression score, the aircraft speed, here V_aeronef_def_l, is not constant, but increases throughout the mission.

[0117] The diagram in [Fig. 5] represents the case of a substantially constant aircraft speed. The aircraft speed, here V_aeronef_def_2, is substantially constant from point P2. It can be seen that for a substantially constant aircraft speed, the aging progression score, here SCORE_def_2, is not constant, but increases from point P2' (equivalent to point PI). To obtain a substantially constant aging progression score (i.e., corresponding to SCORE_def_1), a compensation adjustment to the aging progression score must be applied: - between P2' and P2”, the compensation (denoted Al) must be positive (for

[0123] - TERM 6 = "raise the curve"); - at point P2”, the compensation must be zero; - from P2”, the compensation (noted A2) must be negative (to “lower the curve").

[0118] The compensation to be applied must therefore increase during the mission and comply with the three conditions listed above. Point P2” defines an engine life corresponding to a cumulative flight time T(t) = Y.

[0119] In order to have both a substantially constant aircraft speed and a substantially constant aging progression score, it is necessary to apply the compensation of the lightening.

[0120] The diagram in [Fig. 6] represents an embodiment in which the weight reduction compensation is applied. It should be noted that, in this embodiment, the following are defined:

[0121] - a first component, _Comp_FBtime, for example equal to - 0.1 per flight hour (or by "Flight Hours" in English),

[0122] - a second component, _Comp_FBageing, for example equal to -0, l / (EPCT4 / EPCT4New* 100), PPC 1 Comp_FBtime + _CompFBageing x ( 4 ) x [F — T(t)] '

[0124] It is also recalled that the aging progression score, in this embodiment, is equal to: SCORE = I 0'sî" -^(0 < ^1- (TERM1 + TERM2 + TERM3 + TERM4 + TERM5 + TERM6, otherwise

[0125] TERM 6 adds the lightening compensation, TERM 6 being an increasing function, and zero for T(t) = Y. It is observed that the lightening compensation makes it possible to obtain a substantially constant aircraft speed, V_aeronef', from point P3 (equivalent to points PI and P2') and a substantially constant aging progression score, SCORE, from point P3' (equivalent to point P2).

Claims

Demands

1. A method for piloting assistance for an operator, for example a pilot, or for an automated system, for example an autopilot, said assistance relating to at least one cumulative aging (CV), for example the finning, of at least a part of a gas turbine of an aircraft during a mission of said aircraft, said method comprising a step for determining an aging progression score (SCORE) which is a function of a plurality of terms comprising TERM 1, TERM 2, TERM 3, TERM 4 and TERM 5, and the following are defined for the calculation of the aging progression score (SCORE): — the mission quota, q _ Qpactor * QFactorWjnff * ——— ' Or QFactor is a factor, for example between 0.1 and 10, which should be modifiable by the operator if possible; QFactorageing is a factor; DQcible QFactor^n^a = —:--- SD is a major maintenance trigger threshold of a cumulative aging counter CV, in hours, DQ. jhl cst 'a target service life of said part of the gas turbine, in hours, over an engine life before major maintenance or minimum power margin reached, DQ is the service life between two overhauls of said part of the gas turbine, in flight hours, preferably a target service life for the current flight, assuming that all flights are made with the same power margin, [2 / 1 (EPCT4 ) x (DQtarget — DQmin) — (EPCT4 ) x (DQ-max — DÇmin) -----—-------? -----— ----=-------- x EP CT4 EPC- x ) -epcT4„ xEPCT4m [ePCT4mo^ x (DQmax - DQmin) - EPCT4!,lew x (DQtarget - DQmin) Fr T? ï * Ota.) EPCT4 X (EPC7-4) — EPCT4 x epcT4 1*Avg [x 1 V / ms - the mission's default quota, n _ sa ^DEF nQcible - a measure of the engine's current power margin, EPCT4, for example between 0 and 10, - a verification margin for the estimated power of a new engine, EPCT4New, for example equal to 10, - an average margin for verifying the power of a new engine, EPCT4Moy = X* EPCT4New, - a coefficient X, X preferably being equal to 1 / 3, - a minimum duration, DQmin, of the major maintenance trigger threshold for the engine, for example if it were to operate for its entire life without power margin, such as EPCT4 = 0, - a maximum duration, DQmax, of the major maintenance trigger threshold for the engine, for example if it were to operate for its entire life with the maximum power margin, such as EPCT4Moy = EPCT4\ew for example DQmax= DQcible *3, - the cumulative aging counter CV, which is a value proportional to the cumulative aging, the planned flight duration of the mission entered in hours, M, for example between 0.2 and 3h, - the default estimated flight time of the mission in hours, ^def, for example on the order of 1 hour, - the cumulative flight time of the mission, in hours, at a time t of the mission, T(t) - a first SI threshold, for example between 0.3 and 0.8, for example equal to 0.5, - a second threshold S2, for example between 3 and 10, for example equal to 5, - the start of the mission defined by the time t= tO of the start of flight, - a time t= tl of the end of a phase called the start of the mission, also defined so that: — tl - tO is greater than a duration between 1 and 15 minutes, and / or — tl is the first instant t greater than tO for which the aircraft's flight speed is greater than a predetermined speed, for example 40 Ktas for a helicopter, and / or — tl is the first instant t greater than t0 for which the aircraft's altitude relative to the ground, also called ground clearance, is greater than a determined value, for example 500 feet, - a sliding duration X in seconds, for example including between 10 and 30 seconds, for example around 20 seconds, the average gradient sliding over X seconds, A(t) = CV(t) - CV(tX), Q*( ) the cumulative flight hours since the start of mission tO, at a given moment t of the mission without information on flight duration mission forecast M, = CV (t)--CV (t0) 1 ' Q * T(t) the cumulative flight hours since the start of the mission, at a given time t of the mission, anticipating a flight duration of "usual short missions" of Y, in hours, Y being a parameter to be adapted to the application context, chosen between MD£f / 2 and MD£f, cv(t)_cv(t0) , “Q*max(Y,T(t)) the cumulative total per flight hour since the start of the mission, at a instant t of the mission anticipating the projected flight duration mission details provided M, — CV ftOl ' o(t) = _Lz---- 7 Q * M TERM 1 = I1'> S (otherwise, 0 r 2. if t > tl and M = MDEF and Q = QDEF and D(t) > (T(t) / M), TERM2 = {otherwise, if t > tl and if the trend of B(t) over X seconds is monotonically increasing, t otherwise, 0 i 2, if t>tlet M = MDEF and Q = QDEF and C(t) > 1, TERM 3 = otherwise 1, if t > tl and (M MDEF or Q =F QDEF) and C(t) > 1, (otherwise, 0 fl.si t > tl and (M ï MDEF or Q QDEF) and D(t) > (T(Q / M) 1 d KM 4 — > . otherwise, 0 , And TERM 5 = fl, if t > tl and ( M MDEF or Q QDEF ) and D(t) > 1 , otherwise, 0 said process comprising a step of providing information of said at least one cumulative aging to the operator or the automated system for said piloting assistance, according to said aging progression score (SCORE).

2. A method according to the preceding claim, wherein the aging progression score (SCORE) is defined as follows: STnoF-f 0, siA(t) <ST {TERM1 + TERM2 + TERM3 + TERM 4 + TERM5, sinon

3. Method according to claim 1, wherein the calculation of the aging progression score (SCORE) is further defined as follows: - a first component, _Comp_FBtime, for example equal to -0.1 per flight hour, - a second component, _Comp_FBageing, for example equal to -0, l / (EPCT4 / EPCT4New* 100), TERM 6 = \_Comp_FBtime + _Comp_FBageing X )] X [K - T(t)] EPCT4New J the plurality of terms further comprising TERM 6.

4. A method according to the preceding claim, wherein the aging progression score (SCORE) is defined as follows: f 0,SI zUf) < SI Sï ( / nr = 4 (TERM1 + TERM2 4- TERM3 + TERM4 4- TERM5 4- TERM6, otherwise

5. A method according to claim 3, wherein the aging progression score (SCORE) is defined as follows: SCORE = TERM1 + TERM2 + TERM3 + TERM4 + TERM5 + TERM6, said method further comprising a step of determining an inverse aging progression score defined as follows: 100, if SCORE < 1; INCORE SCORE = 1; MAX {0; (-- * SCORE 4--)}[* 100, otherwise]; and said method further comprising a step of providing inverse information on said at least one cumulative aging. the operator or the automated system for said piloting assistance, according to said inverse aging progression score.

6. A method according to any one of the preceding claims, wherein the cumulative aging is from fining, and / or oxidation, and / or corrosion.

7. A method according to any one of the preceding claims wherein said method is capable of providing information concerning at least two different cumulative agings, the individual score of each aging being determined and a general score being calculated on the basis of said individual scores, for example in the form of an average or a weighted average, the information of said at least one cumulative aging to be provided to the user being dependent on said general score.

8. A method according to any one of the preceding claims, wherein it is determined whether t is out of the start phase of the mission by means of a flight time elapsed since the start of the mission, and / or the flight speed of the aircraft, and / or the altitude of the aircraft relative to the ground.

9. A method according to any one of the preceding claims, wherein the level or quantity of information of said at least one cumulative aging provided to the operator varies according to the aging progression score, and / or the value of A(t), and / or the flight phase concerned.

10. Aircraft comprising a display unit configured to provide information on at least one cumulative aging, said information being derived from a flight aid method according to any one of the preceding claims.

Images