Pilot assist method for managing at least one cumulative ageing process

Abstract

The invention relates to a pilot assist method for an operator, for example a pilot, or for an automated system, for example an autopilot, relating to at least one cumulative ageing process, for example creep, in at least one portion of a gas turbine of an aircraft during a mission of the aircraft, wherein the method comprises a step of determining an ageing progression score (SCORE) that is a function of a plurality of terms, the plurality of terms comprising TERM1, TERM2 and TERM3, and wherein the method comprises a step of supplying information on the at least one cumulative ageing process to the operator or to the automated system for the pilot assist, on the basis of the ageing progression score (SCORE).

Description

[0001] DESCRIPTION

[0002] TITLE: Pilot assistance method for managing at least one cumulative aging

[0003] Technical field of the invention

[0004] 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, relating to at least one cumulative aging, for example creep, of at least one part of a gas turbine of an aircraft during a mission of said aircraft.

[0005] State of the prior art

[0006] An aircraft pilot generally has access to piloting indications relating to propulsion systems, displayed in the cockpit. These indications refer in particular 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.

[0007] Such limits are, for example, N1 (gas generator rotation speed at the high-pressure shaft), the T45H conformal temperature of the high-pressure turbine, the torque of the power shaft, or an indicator combining this information. These limits constitute, for example, thresholds not to be exceeded in stabilized flight, and for which maximum continuous operating times may be defined by regulation.

[0008] 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 modes from leading to a need for premature overhaul of the turbomachine, for example before its scheduled general overhaul.

[0009] In the context of relatively unpredictable and variable uses, such as airliner missions, there are predictive methods that set binary throttle position indices that correspond correctly to maintenance costs. These predictive methods also most often include maintenance costs and fuel consumption costs.

[0010] For versatile uses, for example for the varied missions of helicopters, the correspondence of a binary instruction (whether it be a torque, a gas generator speed or a temperature) with the costs is however not reliable. Today, in this context, only ground monitoring of the meters exists, in particular with regard to creep, carried out manually or with tools. However, in this context, concerning these complex cumulative agings, such a posteriori monitoring does not provide any useful prospective indication for the following flights and is not in the nature to help the pilot to respect a cumulative objective during the flight, for example an objective given by a fleet manager.

[0011] Such monitoring or indications also do not provide information that would enable the pilot to understand and develop an intuition of the actions to be taken to manage aging modes. Indeed, these aging phenomena are multi-factorial and non-linear. Consequently, a pilot cannot develop a reliable intuition of the conditions under which these aging modes accelerate or slow down, without additional indication.

[0012] Cumulative aging is a form of damage that increases over time. Such aging is perfectly consistent with the phenomenon of turbine blade creep, in the context of the intended application, but can also be oxidation, corrosion, or mechanical wear of parts (friction wear or bearing wear, for example).

[0013] Other types of aging can also occur, such as predominantly "cyclic" aging modes, relating to a number of times stress thresholds are crossed, both upwards and downwards (oligocyclic fatigue (LCF), thermal cycling, number of starts / stops, etc.). However, it is difficult to act on such cyclic aging.

[0014] Presentation of the invention

[0015] This document aims to address the above-mentioned drawbacks.

[0016] For this purpose, the present document proposes a piloting assistance method for an operator, for example a pilot, or for an automated system, for example an autopilot, relating to at least one cumulative aging, for example creep, of at least one 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, said plurality of terms comprising TERM1, TERM2, and TERM3, and for the calculation of the aging progression score, the following are defined:

[0017] Q — Q Factor the mission quota, , Or

[0018] - QFactor is a factor between 0.1 and 10, for example, to be made modifiable by the operator if possible, - SD is a major maintenance trigger threshold for a cumulative aging counter CV, in hours,

[0019] - DQ is the flight duration between two overhauls of said part of the gas turbine or the target life of said part of the gas turbine, in hours, the default quota of the mission,

[0020] Q - g 5 the maximum quota, M AX = a * Q DEF , with a > 5, the minimum quota, Q M / W = p * DEF , with 0 < p < 1, the cumulative aging counter CV which is a value proportional to the cumulative aging, the forecast flight duration of the mission entered in hours, M, for example between 0.2 and 3 hours, the default forecast flight duration of the mission in hours, M DFF , for example of the order of 1 hour,

[0021] Y a parameter to adapt to the application context, chosen between M DFF / 2 and M CFFthe cumulative flight duration of the mission, in hours, at a time t of the mission, T(t), a first threshold S1, 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 is defined by the time t= t0 of the start of the flight, a time t= t1 of the end of a phase called the start of the mission is also defined so that:

[0022] -- 11 - tO greater than a duration between 1 and 15 minutes, and / or

[0023] -- 11 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 Ktas for a helicopter, and / or

[0024] -- 11 is the first instant t greater than t0 for which the altitude of the aircraft 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 between 10 and 30 seconds, for example of the order of 20 seconds, the average sliding gradient over X seconds, the cumulative flight time per hour since the start of mission tO, at a time t of the mission CV (t) ~ CV (tO) without information on the forecast flight duration of mission M, the cumulative flight time per hour since the start of the mission, at a time t of the mission, anticipating a flight duration of the “usual short missions” of Y, in hours, 5 the cumulative total per flight hour since the start of the mission, at a time t of the mission anticipating the forecast mission flight duration entered M, 5 said method comprising a step of providing information on said at least one cumulative aging to the operator or to the automated system for said piloting assistance, according to said aging progression score.

[0025] The step of providing said information to an operator can be carried out by display.

[0026] The coefficient y can be equal to 2, the aging progression score being defined as follows:

[0027] SCORE TERM 1 + TERM 2 + TERM 3 said method further comprising a step of determining an inverted aging progression score defined as follows: 100, otherwise and said method further comprising a step of providing reverse information of said at least one cumulative aging to the operator or to the automated system for said piloting assistance, according to said reverse aging progression score.

[0028] Defining the aging progress score as a sum of TERM1 , TERM2 and TERM3 results in a continuous aging progress score (as opposed to a discretized aging progress score). If there is a step of determining the reverse aging progress score in the process, the reverse aging progress score will also be continuous accordingly.

[0029] The aging progression score can in some cases be too demanding for the operator, because he must adjust the piloting to a median value and therefore be tempted to control the situation more often. Providing reverse information following the reversed progress score allows the operator to adjust the piloting to 100% and to consider that if he does not have the opportunity to control later, the objective will still be globally achieved. Conversely, this can prevent him from seeing possibilities of increasing the flight conditions in particular cases (for example: significant payload deposition mid-mission). The choice to exploit the information or the reversed information following the aging progression score or the reversed aging progression score respectively is a choice arbitrated by the operator.

[0030] The reverse aging progression score provides a clipped result.

[0031] Optionally, the reverse aging progression score can be rounded up to the nearest fifth, down to the nearest fifth (e.g., minimum desirable resolution), or truncated to the nearest fifth, down to the nearest fifth. Optionally, the reverse aging progression score can be rounded up to the nearest hundredth, down to the nearest hundredth, or truncated to the nearest hundredth, down to the nearest hundredth.

[0032] QMAX and QMIN are used to define the sensitivity zone of TERM 1 and TERM 2.

[0033] QMAX is a high threshold (or high sensitivity threshold) which allows the calculation ceiling to be reached and then clipped above (i.e. clipping the plurality of terms of the score so that the score is less than or equal to the ceiling).

[0034] QMIN is a low threshold (or low sensitivity threshold) which allows reaching the floor 0 and then clipping below (i.e. clipping the plurality of terms of the score so that the score is greater than or equal to the floor).

[0035] The coefficient y can be equal to 1, the aging progression score being defined as follows: The coefficient y makes it possible to adjust the sensitivity of the aging progression score to variations in unstabilized flight phases, the coefficient being proportional to this sensitivity. The fact that the coefficient y is equal to 1 therefore makes it possible to reduce the sensitivity.

[0036] As previously stated, cumulative aging of a gas turbine part is the damage to the affected part that increases over time. Such aging is mainly the creep phenomenon, but can also be oxidation, corrosion, or mechanical wear of the parts of the affected part.

[0037] The cumulative aging counter CV is a value generally provided by the gas turbine computer, and proportional to the cumulative aging, measured or determined by calculation, from values ​​from sensors (gas generator rotation speed, temperature within the gas turbine, torque, outside temperature, deformations, etc.). The higher the CV value, the greater the cumulative aging of the parts of the concerned part or module of the gas turbine.

[0038] 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.

[0039] The major maintenance trigger threshold is a threshold predetermined 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 prevent premature damage to it. Such an operation generally requires the removal of the gas turbine.

[0040] The flight time between two general overhauls is known by the abbreviation TBO for "Time Between Overhauls".

[0041] The target life D can be a flight duration greater than the time between two overhauls, for example equal to twice the time between two overhauls.

[0042] The predicted flight duration of the mission entered M is a value determined before the start of the mission and entered into an aircraft computer, for example via an interface. This duration can be entered by an operator, for example a pilot.

[0043] The expected flight duration, by default or not, of the mission entered M or MDEF is for example between 0.2 and 3 hours. MDEF is for example of the order of 1.5 hours.

[0044] M will be filled in with the collection value of MDEF if M is not filled in by the operator.

[0045] The flight duration of the usual short missions Y will either be defined in a fixed way for a given application, for example of the order of 0.8 hours if MDEF = 1.5 hours, or determined by the application and calculated as an average of the flight durations of the previous missions of the aircraft less than MDEF in the interval, of M DFF / 2 to M DFF . The Y parameter can be adapted for example in this interval depending on whether we have more or less mission frequencies much shorter than MDEF.

[0046] The cumulative flight duration of the mission at time t, T(t) is the time elapsed between the start of the mission tO and time t.

[0047] The sliding CV value over X seconds at time t is equal to the difference between the CV values ​​at time t and CV at time tX.

[0048] 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, of the order of 500ms for example.

[0049] Each term serves a different purpose and therefore allows them to be combined.

[0050] When the engine load level at time t leads to minor aging (S1 to be defined by the engine manufacturer), the score is set to zero, regardless of the value of the various terms. There is in fact no point in providing information, for example by display, if the engine load no longer significantly changes the final total, and there is no need to continue to encourage a reduction in the load. This avoids unnecessarily limiting solutions operationally since exceeding the quota does not involve any risk and the following missions always offer compensation possibilities.

[0051] The first term TERM 1 is used to signal to the operator a very high demand, without any obvious relationship to the indications of acceptable speed limits. This is a first sign for the operator that the current flight conditions may lead to significant cumulative aging, and it can be displayed from the very first moments of the flight. It is also regular information that enriches the operator's intuitive perception of the situation.

[0052] The second term TERM 2 allows the score to be reinforced if the level of stress at time t leads to an increase in aging not compensated by the increase in mission flight duration, versus the quota Q, or greater than a linear progression (if the values ​​M and Q are not defined by the operator). This indication reinforces the score when, at the start of the mission in particular, the stress is carried out at a high rate. It is an intermediate variant between the gradient and the cumulative aging which integrates any previous debits and credits and allows a signal in the first part of the mission. It gradually loses relevance with the lengthening of the mission and then no longer contributes to the score, unless the stress remains truly excessive.In addition, the second term TERM 2 allows the score to be reinforced if the cumulative score follows a progression greater than a linear cumulative score towards the quota Q entered, for the mission flight duration M entered. As the start of the mission is generally more demanding, this allows vigilance to be reinforced early enough and precisely enough, and indicates that moderation or pilot action is desirable.

[0053] The third term TERM 3 allows the score to be increased if the quota is exceeded by considering that the mission will last Y hours and to lower the score if, after the flight duration Y has been exceeded, the cumulative total has converged again below the quota. This term allows a first level of progression of the score in absolute value of the cumulative hourly total, avoiding an untimely increase in the score at the start of the mission if the minimum duration of Y hours was not used (reason why B(t) is not used in absolute value). In addition, the third term TERM 3 allows the score to be increased by comparing the cumulative total to the quota Q, in particular in a case where it is not possible to remain within the quota during the mission, but it is still possible to limit the excess.

[0054] Such a method can also provide piloting assistance and / or training for the operator of critical conditions leading to an aggravation of said cumulative aging.

[0055] It is also possible to freeze the score display during transient flight phases when the pilot is otherwise occupied. Such a phase can be determined in particular by a strong variation in the sliding average (for example over a given period) of the engine torque, outside a reduced range (for example +-5%) around the sliding average. This allows the display to be frozen during such maneuvers.

[0056] It is also possible to display a warning light, for example a green one, if A(t) < S1 (or other value) in the aircraft engine speed limits display area (first limit indicator, N1 margin, T45H - defined above), this area being a priority attention area for the pilot. It is also possible to manage the case of several cumulative agings (both creep and corrosion for example, which are two different cumulative agings).

[0057] The calculated terms are relatively stable, but instabilities may exist. To compensate for such instabilities, it is possible to add hysteresis to the score display. Some terms may have a suitable hysteresis, for example, a greater one than other terms. Cumulative aging may be creep, and / or oxidation, and / or corrosion.

[0058] Said method can provide information concerning at least two different cumulative agings, the individual score of each aging being determined and a general score is calculated on the basis of said individual scores, for example in the form of an average or a weighted average, the information provided to the user being dependent on said general score.

[0059] Whether or not t is outside the mission start phase can be determined using elapsed flight time since the start of the mission, the aircraft's flight speed, and / or the aircraft's altitude above the ground.

[0060] The level or quantity of information provided to the operator may vary depending on the aging score, the value of A(t) and / or the flight phase concerned. The level of information may notably vary progressively by increments, for example by displaying a value between 0 and 5 or by displaying a progress bar, or by not displaying such a value or by not displaying it outside of stabilized flight phases.

[0061] The amount of information can also be varied by adding or removing information, so as to have more or less detailed information depending on the situation.

[0062] In particular, it is possible that no information is provided (e.g. no display), in certain critical flight phases, for example during the mission start phase, or if the aging is low (low score or A(t)). Increasingly complex information (different levels of information) may be provided or displayed depending on the flight phases, the aging, or at the operator's request.

[0063] 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 degrees of detail or according to the flight phases), whatever the aircraft and the installation (single or multi-engine).

[0064] These indications are preferably not unnecessarily disruptive, particularly in flight phases that require particular attention from the pilot. (For example, they will be displayed so as to be visible during long phases - cruising or climbing flight (discreet flashing for example) - and in a constant, non-distracting, or even inhibited display (no flashing, etc.) during phases with significant power variations),

[0065] These indications encourage and guide pilots to act on long and stable phases of flight, for the management, flight after flight, of cumulative aging of major components of the propulsion system. As previously indicated, these indications can be adjusted according to the score or previous cumulative aging, according to the types and business objectives of the missions, and the operating context.

[0066] These indications must be progressive (several alert levels rather than a binary alert), such progressiveness being particularly useful when aging is difficult to predict, the short-term consequences are minor, the use of the aircraft is versatile, and to provide the pilot with a perception of flight conditions that produce cumulative aging (non-intuitive without indication or with a binary indication).

[0067] Such indications make it possible to identify the phases which cause more or less pronounced cumulative aging, and can also contribute to more ecological management decisions (CO2 emissions, etc.).

[0068] Unlike existing applications in a non-versatile usage context, this score does not derive from an invariable cost calculation.

[0069] Here, the fleet manager, keen to get the most out of his gas turbines, will be able, by following the trend a posteriori, to modify the quota and the score instructions to be respected by the pilot to enable the pilot to manage a globally controlled cumulative aging trajectory. He will be able to do this by considering all the versatility of his priorities, the geographical context of operation, seasonality, the age of the engines, the needs for protection of the air intakes, and all the other influential factors, by a pragmatic method of learning and instructions using the graduation of the invention.

[0070] On the other hand, a combination with fuel-efficient condition indicators is a logical association with this indicator, for example the addition of a fuel economy score of 0 to 2 depending on the deviation from the most economical stable flight conditions.

[0071] 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 pilot assistance method of the aforementioned type.

[0072] The aircraft may be a rotary-wing aircraft, particularly a helicopter. The display unit may be an information bar.

[0073] Brief description of the figures

[0074] [Fig. 1] is a trend diagram illustrating the evolution over time of a mission (i.e. on a mission), this diagram representing the aging progression score according to an embodiment, and a previous aging progression score, during a mission of the aircraft,

[0075] [Fig. 2] is a trend diagram illustrating the evolution over time of a mission, this diagram representing the reversed aging progression score, according to the embodiment of Figure 1, and a previous aging progression score, during a mission of the aircraft,

[0076] [Fig. 3] is an example of displaying to the operator an information bar of a life of the blades of an aircraft in a state, following the previous score of aging progress,

[0077] [Fig. 4] is an example of displaying to the operator an information bar of a life of the blades of an aircraft in the state of Fig. 3, following the aging progression score, according to the embodiment of Fig. 1, and

[0078] [Fig. 5] is an example of displaying to the operator an information bar of a life of the blades of an aircraft in the state of Fig. 3, following the aging progression score, according to the embodiment of Fig. 2.

[0079] Detailed Description of the Invention An example of a prior art aging progression score, referred to as Prior SCORE in Figures 1 and 2 or Prior Aging Progression Score, is defined as follows: for the calculation of which we define: the mission quota, where

[0080] • QFactor' is a factor between 0.1 and 10, for example, to be made modifiable by the operator if possible,

[0081] • SD' is a major maintenance trigger threshold for a cumulative aging counter CV', in hours,

[0082] • DQ' is the flight duration between two overhauls of said part of the gas turbine or the target life of said part of the gas turbine, in hours. the default quota of the mission, the cumulative aging counter CV', which is a value proportional to the cumulative aging the forecast flight duration of the mission entered in hours, M', for example between 0.2 and 3 hours, to be made modifiable by the operator if possible, the default forecast flight duration of the mission in hours, M DFF ', for example of the order of 1 hour,

[0083] Y' a parameter to adapt to the application context, chosen between M DFF 72 et M CFF' the cumulative flight duration of the mission, in hours, at a time t of the mission, T'(t) a first threshold S1 ', 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 is defined by the time t = t0' of the start of the flight a time t = t1 ' of the end of a phase called the start of the mission is also defined so that:

[0084] - t1 ' - tO' greater than a duration between 1 and 15 minutes, and / or

[0085] - t1 ' 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 Ktas for a helicopter, and / or - t1 ' is the first instant t greater than t0' for which the altitude of the aircraft 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 between 10 and 30 seconds, for example of the order of 20 seconds, the average sliding gradient over X' seconds, the cumulative total per hour of flight since the start of the mission (t0'), at a time t of the mission without information on the forecast flight duration of mission M', 5

[0086] - the cumulative flight time per hour since the start of the mission, at a time t of the mission, anticipating a flight duration of the “usual short missions” of Y', in hours, 5 the cumulative total per flight hour since the start of the mission, at a time t of the mission anticipating the forecast mission flight duration entered M', health: , 5 5 and

[0087] Reference is now made to Figure 1 which compares this prior aging progression score, prior SCORE, with the aging progression score, SCORE, according to one embodiment. In this embodiment, we define: SCORE - TE RM 1 TERM 2 + TERM 3

[0088] SCORE and SCORE anterior present substantially similar evolutions. However, SCORE anterior is a discretized score, unlike SCORE. Indeed, SCORE anterior presents abrupt variations between different constant values ​​(for example between points P1 and P2), and SCORE presents a continuity which is due to its expression with a sum of TERM1, TERM2 and TERM3. This continuity results in a better resolution and a better sensitivity. In this way, SCORE allows the operator to have more precise and faithful information for piloting assistance compared to SCORE anterior.

[0089] Reference is now made to Figure 2 which compares the prior aging progression score, SCOREprior, with the reversed aging progression score, SCOREJnversé, according to the embodiment of Figure 1. In this embodiment, we define: )}} » 100, otherwise

[0090] Reversed SCORE is also continuous, unlike previous SCORE.

[0091] The clipping above SCOREJnversé is shown in Figure 2. Indeed, it can be seen that when SCOREJnversé reaches 100% at point P, the clipping is carried out, while SCORE illustrated in Figure 1 has not reached a zero value for a point P' with the same abscissa as point P. As mentioned in the presentation of the invention, the choice of using the information or the inverted information according to the aging progression score or the inverted aging progression score respectively is a choice arbitrated by the operator. Indeed, the aging progression score and the inverted aging progression score each have their advantage.

[0092] Figures 3 and 4 show an example of displaying to the operator an information bar 3 of a lifespan of the blades of an aircraft in the same first state. Figure 3 illustrates the display according to the previous aging progression score SCORE and Figure 4 illustrates the display according to the aging progression score, SCORE, according to one embodiment.

[0093] Prior SCORE is discretized can only include the integer values ​​0; 1; 2; 3; 4; and 5 which correspond to filling the information bar 3 up to the fill line 30, 31, 32, 33, 34, 35 respectively. As illustrated in Figure 3, Prior SCORE is equal to 3 and the progress bar 33 is filled up to line 33. For Prior SCORE, this state corresponds to point P3 in Figure 1. SCORE is continuous and can include decimal values ​​between 1 and 6. In the embodiment of Figure 4, the information bar 3 is enlarged to include a sixth box between line 35 and a fill line 36. SCORE is equal to approximately 2.3 and progress bar 3 is filled up to the intermediate line 32' located between line 32 and line 33. For SCORE, the state corresponds to point P4 in Figure 1, P4 having the same abscissa as P3.It is observed that SCORE offers better intuition and better judgment of blade flight defects to the operator, in particular thanks to continuity and better resolution (i.e. thanks to decimal values ​​between 1 and 6).

[0094] The fact that the information bar 3 has a sixth box is optional, other embodiments do not have the sixth box since a clipping can be carried out (to keep a score less than or equal to 5). For example, this clipping can be carried out with a display following the reversed aging progress score SCOREJnversé, like that of figure 5.

[0095] ReversedScore is continuous and can include percentage values ​​between 0% (fill line 30) and 100% (fill line 35). As shown in Figure 5, ReversedScore is equal to 90% and progress bar 3 is filled up to line 34'. For ReversedScore, the state corresponds to point P5 in Figure 2, where P5 has the same abscissa as P3. The pilot can, for example, understand that he must adjust the piloting for the rest of the mission to a displayed value of 100%, which he will soon reach.

Claims

CLAIMS 1. Piloting assistance method for an operator, for example a pilot, or for an automated system, for example an autopilot, relating to at least one cumulative aging, for example creep, of at least one 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 (SCORE) which is a function of a plurality of terms, said plurality of terms comprising TERM1, TERM2, and TERM3, and for the calculation of the aging progression score (SCORE) it is defined: Q ~ QFaetor * the mission quota, ,jQ , Or - QFactor is a factor between 0.1 and 10, for example, to be made modifiable by the operator if possible, - SD is a major maintenance trigger threshold of a cumulative aging counter CV, in hours, - DQ is the flight duration between two overhauls of said part of the gas turbine or the target life of said part of the gas turbine, in hours, the default quota of the mission, , the maximum quota, MAX = a * Q DE F, with a > 5, the minimum quota, Q M / W = p * Q CFF , with 0 < p < 1, the cumulative aging counter CV which is a value proportional to the cumulative aging, the forecast flight duration of the mission entered in hours, M, for example between 0.2 and 3 hours, the default forecast flight duration of the mission in hours, M DFF , for example of the order of 1 hour, Y a parameter to adapt to the application context, chosen between M DFF / 2 and M CFFthe cumulative flight duration of the mission, in hours, at a time t of the mission, T(t), a first threshold S1, 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 is defined by the time t= t0 of the start of the flight, a time t= t1 of the end of a phase called the start of the mission is also defined so that: -- 11 - tO greater than a duration between 1 and 15 minutes, and / or -- 11 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 Ktas for a helicopter, and / or -- 11 is the first instant t greater than t0 for which the altitude of the aircraft 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 between 10 and 30 seconds, for example of the order of 20 seconds, the average sliding gradient over X seconds, the cumulative total per flight hour since the start of mission tO, at a time t of the mission without information on the forecast flight duration of mission M, the cumulative flight time per hour since the start of the mission, at a time t of the mission, anticipating a flight duration of the “usual short missions” of Y, in hours, the cumulative total per flight hour since the start of the mission, at a time t of the mission anticipating the forecast mission flight duration entered M, TERM3- fsi fn: 2 xf.4 {D; MIN[1; C(OJ) ' " I. otherwise, 0 5 said method comprising a step of providing information on said at least one cumulative aging to the operator or to the automated system for said piloting assistance, according to said aging progression score (SCORE).

2. Method according to the preceding claim, in which y is equal to 2, the aging progression score (SCORE) being defined as follows: SCO = TERM 1 + TERM 2 + TERM 3 said method further comprising a step of determining an inverted aging progression score (invertedSCORE) defined as follows: 100, otherwise and said method further comprising a step of providing reverse information of said at least one cumulative aging to the operator or to the automated system for said piloting assistance, according to said reverse aging progression score (SCOREJnversé).

3. Method according to claim 1, in which y is equal to 1, the aging progression score (SCORE) being defined as follows:

4. A method according to any preceding claim, wherein the cumulative aging is creep, and / or oxidation, and / or corrosion.

5. Method according to any one of the preceding claims, in which 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 is calculated on the basis of said individual scores, for example in the form of an average or a weighted average, the information to be provided to the user being dependent on said general score.

6. A method according to any preceding claim, wherein it is determined whether or not t is outside the mission start phase using a flight time elapsed since the start of the mission, the flight speed of the aircraft and / or the altitude of the aircraft relative to the ground.

7. Method according to any one of the preceding claims, in which the level or quantity of information provided to the operator varies according to the aging score, and / or the value of A(t), and / or the phase of flight concerned.

8. A method according to any preceding claim, wherein the aircraft is a rotary wing aircraft.

9. Aircraft comprising a display unit (3) configured to provide information on at least one cumulative aging, said information coming from a pilot assistance method according to any one of the preceding claims.

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