Method and device for determining and providing a ranking, according to their environmental impact, of a plurality of distinct aeronautical flights

Abstract

Method and device for determining and providing a ranking, according to their environmental impact, of a plurality of distinct aeronautical flights. The present invention relates to a method (50) for determining and providing a ranking, according to their environmental impact, of a plurality of flights comprising - for each flight: - discretization (58) of its trajectory into a plurality of segments; - for each segment: - determination (64) of the value of the nitrogen oxide emission index; - obtaining (66) the quantity of nitrogen oxides emitted on said segment; - obtaining (76) the total quantity of nitrogen oxides, by summing the quantities on each segment; - conversion (78) of said total quantity into carbon dioxide equivalent using a predetermined metric and determination (80) of an environmental impact score; - determination (98) and provision of a ranking (99) of said plurality of flights, ranked by decreasing value of said score.Figure for the abbreviation: Figure 2.

Description

Title of the invention: Method and device for determining and providing a ranking, according to their environmental impact, of a plurality of distinct aeronautical flights

[0001] The present invention relates to a method for determining and providing a ranking, according to their environmental impact, of a plurality of distinct aeronautical flights, the method being implemented by an electronic device.

[0002] The invention also relates to a computer program comprising software instructions which, when executed by a computer, implement such a process.

[0003] The present invention also relates to an electronic device for determining and providing a ranking, according to their environmental impact, of a plurality of distinct aeronautical flights.

[0004] The invention is in the field of aeronautics, and more specifically in the optimization of air operations for the purpose of reducing the associated environmental footprint.

[0005] Climate change is a current issue. The radiative forcing from air transport was estimated in 2005 at nearly 5% of global anthropogenic radiative forcing (3.5% excluding contrails).

[0006] The aeronautical industry has already made significant scientific progress in improving the environmental efficiency of flight, particularly in terms of weight reduction, aerodynamics, and propulsion. Despite this, emissions from the aviation sector are increasing due to traffic growth, estimated at over 3.6% per year.

[0007] Optimizing flight operations appears to be an intermediate step towards achieving rapid benefits. Indeed, it could potentially reduce the sector's carbon footprint by 10% by 2030.

[0008] Until now, the sector has attached a lot of importance to CO2 carbon dioxide emissions, but recent studies have shown that CO2 is not the only consequence of air operations since non-CO2 effects account for more than 66% of the sector's radiative forcing.

[0009] Indeed, emissions due to fuel combustion can be classified into two categories, on the one hand primary jet fuel combustion products such as carbon dioxide CO2, Water (H2O) and sulfur oxides (SOx, SO2, SO3), which are a direct result of combustion and therefore have a constant emission index. This means that the amount of gas emitted is proportional to the amount of fuel consumed (this proportionality factor being constant).

[0010] The second category, on the other hand, corresponds to secondary jet fuel combustion products such as nitrogen oxides (NOx, NO2, nitrous oxide, etc.), carbon monoxide (CO), HC (unburned hydrocarbons), PM (particularly particulate matter), and VOCs (volatile organic compounds), which depend on the nature of the combustion process and the engine load. They therefore have an emission index that varies during flight depending on the engine type, engine operating conditions, and atmospheric conditions.

[0011] Currently, however, estimating the amount of nitrogen oxides (NOx) emitted during a flight is very complex. Indeed, there are complex models, such as, for example, the "Boeing Fuel Flow Method 2" (BFFM2). Such models allow access to the NOx emission index (EINOx) but have the drawback of covering a limited number of aircraft.

[0012] There are several studies which aim to reduce the non-CO2 environmental impact of a flight by trajectory optimization.

[0013] However, these trajectory optimizations are often carried out by focusing on a single type of non-CO2 emission, such as, for example, that associated with contrails (from the English contrailsf), whereas non-CO2 emissions are associated with non-CO2 effects of several kinds, such as aerosol-cloud interactions, aerosol-radiation interactions, stratospheric water vapor, nitrogen oxides, with emissions associated with contrails and also with nitrogen oxides being the non-CO2 emissions having the most significant radiative forcing.

[0014] The uncertainties related to these emissions associated with these effects of distinct natures, as well as their different lifetimes, have further led scientific research to study each non-CO2 effect separately, and there is currently no consensus on the choice of a metric to express the impact of each of the emissions associated with these effects of distinct natures.

[0015] Furthermore, with the current growth in air traffic and the associated operational constraints, it is neither relevant nor possible to try to optimize the trajectory of all flights, especially since numerous studies have shown that only a small percentage of flights are responsible for the majority of emissions non-CO2 of the sector, because non-CO2 effects are not created uniformly by all flights.

[0016] Moreover, current trajectory optimizations often remain theoretical and unrealizable, as they are unsuitable for concrete implementation given the operational difficulties generally caused by a change of trajectory (i.e. flight plan).

[0017] The aim of the invention is therefore to propose a solution upstream of the aforementioned trajectory optimization, in order to identify the most suitable flights to be optimized in order to reduce their environmental impact.

[0018] To this end, the invention relates to a method for determining and providing a ranking, according to their environmental impact, of a plurality of distinct aeronautical flights, the method being implemented by an electronic device, and comprising at least the following steps:

[0019] - for each flight of said plurality:

[0020] - obtaining a previously determined nitrogen oxide emission index, said index being a discrete variable comprising, depending on the engine of the aircraft used to perform said flight, four discrete values ​​associated respectively with four distinct flight phases including takeoff, climb, approach, descent;

[0021] - from said index, at least by linear regression, obtaining a model nitrogen oxide emission specific to providing the nitrogen oxide emission index associated with each triplet of input data types including engine thrust, humidity and atmospheric pressure,

[0022] - discretization of the trajectory associated with said flight, according to a constant time step predetermined, in a plurality of trajectory segments;

[0023] - for each segment:

[0024] - determination of a triplet of input data including engine thrust, humidity and atmospheric pressure associated with said segment;

[0025] - from said triplet of input data from said segment and said emission model nitrogen oxides, determination of the associated nitrogen oxide emission index value;

[0026] - using a predetermined fuel flow model, said associated value of the nitrogen oxide emission index and said time step, obtaining the quantity of nitrogen oxides emitted on said segment;

[0027] - obtaining the total quantity of nitrogen oxides emitted on said flight, by summation quantities of nitrogen oxides emitted on each segment of said plurality of segments composing said trajectory of said flight;

[0028] - conversion of said total quantity of nitrogen oxides into quantity of dioxide carbon equivalent CO^NOx, using a predetermined metric of global warming potential;

[0029] - at least from said quantity of carbon dioxide equivalent CO^qNOx associated with the total quantity of nitrogen oxides emitted on said flight, determination (80) of an environmental impact score C for said flight;

[0030] - determination and provision of a classification, according to their environmental impact, of said plurality of distinct aeronautical flights, ranked by decreasing value of said environmental impact score C of each of said flights.

[0031] Thus, the present invention proposes a solution for quantifying the total quantity of nitrogen oxides emitted during each flight and uses this quantity to determine an environmental impact score allowing the comparison and ranking of a plurality of flights according to their environmental impact, and consequently the identification of the most problematic flights at least in terms of nitrogen oxide emissions.

[0032] Furthermore, the conversion carried out in quantity of equivalent carbon dioxide allows a comparison and / or a combination with the quantification of other effects contributing to radiative forcing also expressed in quantity of equivalent carbon dioxide, i.e. on the scale of carbon dioxide CO2.

[0033] In other words, the proposed impact score is a reliable indicator that makes it possible to identify problematic flights whose trajectory it is relevant to modify.

[0034] Thus, the present invention proposes a generic method which makes it possible to consider, at least the non-CO2 emissions due to nitrogen oxide emissions, on the same footing as CO2 emissions, and is upstream of the trajectory optimization as such because it aims beforehand to estimate whether a flight is problematic with regard to non-CO2 emissions (by assigning it a coefficient expressed subsequently) that is to say whether it is wise to implement this trajectory optimization or whether it is preferable to focus on another flight.

[0035] According to other advantageous aspects of the invention, the method for determining and providing a ranking, according to their environmental impact, of a plurality of distinct aeronautical flights, comprises one or more of the following features, taken individually or in all technically possible combinations:

[0036] - said predetermined global warming potential metric is GWP100;

[0037] - said triplet of input data of said segment is determined from a set (63) of previously determined test data;

[0038] - the method further comprises, for each flight of said plurality, the determination of the carbon dioxide equivalent impact associated with at least one trail of persistent condensation of said flight, and its consideration in determining said environmental impact score of said flight;

[0039] - said determination of the carbon dioxide equivalent impact associated with the less a persistent condensation trail from said flight includes:

[0040] - obtaining, as input, a map of the geographical areas of formation of persistent condensation trails from said flight;

[0041] - the superimposition of said mapping with the trajectory of said flight and determination of the length of persistent condensation trail(s) likely to be generated during said flight;

[0042] - obtaining the quantity of carbon dioxide equivalent CO^q contrails associated with at least one length of persistent condensation trail of said flight.

[0043] - said C score of environmental impact of each of said flights also takes into account includes at least one of the following coefficients:

[0044] - a coefficient coeff^TC representing the difficulty of modifying said flight from a point from the point of view of air traffic control;

[0045] - a coefficient representing the difficulty of modifying said flight of a point of view of the airline associated with said flight;

[0046] - said score C is obtained using an equation of the following form:

[0047] c= / < \ Oaxff . \ ref city pairs / J ATC JJ OtrluK

[0048] where ref citypairs cst 'a average of the non-CO2 environmental impact, in terms of nitrogen oxide emissions and persistent condensation trail(s), of the flights for each pair formed by the departure airport and the arrival airport of said flight;

[0049] - said C score also takes into account the CO2 emissions associated with said flight in using an equation in the following form:

[0050] / contraiis^ NOx \ C = 77)-------Trn-------- / f ^coef f . 2rejcityp <iirs^u2eqref<itypmrs / Al Ç airlllll'

[0051] where CO2 ref citypairs cst 'a average of the CO2 environmental impact of flights for each pair formed by the departure airport and the arrival airport of said flight;

[0052] - the method further comprises, for each flight, or for a predetermined number of flight(s) from the top of the ranking, an identification step (102) of the segment(s) of the trajectory presenting the maximum quantity(ies) of non-CO2 emission, or presenting the maximum quantity(ies) of CO2 and non-CO2 emission;

[0053] The invention also relates to a computer program comprising software instructions which, when executed by a computer, implement the steps of the aforementioned method of determining and providing a ranking, according to their environmental impact, of a plurality of distinct aeronautical flights.

[0054] The invention also relates to an electronic device for determining and providing a ranking, according to their environmental impact, of a plurality of distinct aeronautical flights, the device comprising at least:

[0055] - for each flight of said plurality:

[0056] - a first retrieval module configured to obtain an index, previously determined, of nitrogen oxide emissions, said index being a discrete variable comprising, depending on the engine of the aircraft suitable for carrying out said flight, four discrete values ​​associated respectively with four distinct flight phases including takeoff, climb, approach, descent;

[0057] - a second retrieval module configured to obtain, from said index, at less by linear regression, a nitrogen oxide emission model suitable for providing the nitrogen oxide emission index associated with each triplet of input data types including engine thrust, humidity, and atmospheric pressure,

[0058] - a discretization module configured to discretize the audit-associated trajectory flight, according to a predetermined constant time step, in a plurality of trajectory segments;

[0059] - a first determination module configured to determine, for each segment, a triplet of input data including engine thrust, humidity and atmospheric pressure associated with said segment;

[0060] - a second determination module configured to determine, for each segment, from said triplet of input data of said segment and said nitrogen oxide emission model, the value of the associated nitrogen oxide emission index;

[0061] - a third acquisition module configured to obtain, for each segment, the quantity of nitrogen oxides emitted on said segment, using a predetermined fuel flow model, said associated value of the nitrogen oxide emission index and said time step;

[0062] - a fourth production module configured to obtain the total quantity of oxides nitrogen emitted on said flight, by summing the quantities of nitrogen oxides emitted on each segment of said plurality of segments composing said trajectory of said flight;

[0063] - a conversion module configured to convert said total quantity of oxides nitrogen in terms of carbon dioxide equivalent CO^nox, using a predetermined metric of global warming potential;

[0064] - a third determination module configured to determine, at least from of the said quantity of carbon dioxide equivalent CO^qNOx associated with the total quantity of nitrogen oxides emitted on said flight, an environmental impact score C of said flight;

[0065] - a fourth determination module configured to determine and provide a ranking, according to their environmental impact, of said plurality of distinct aeronautical flights, ranked by decreasing value of said environmental impact score C of each of said flights.

[0066] The invention will become clearer upon reading the following description, given solely by way of non-limiting example, and made with reference to the drawings in which:

[0067] [Fig-1] [Fig.1] is a schematic representation of an electronic device determination and provision of a ranking, according to their environmental impact, of a plurality of distinct aeronautical flights, according to the present invention.

[0068] [Fig.2] [Fig.2] is a flowchart of the main steps of a process of determination and provision of a ranking, according to their environmental impact, of a plurality of distinct aeronautical flights, according to the present invention.

[0069] [Fig.3] [Fig.3] illustrates the evolution of the coefficient representing the difficulty in modify a flight from an air traffic control perspective based on traffic density.

[0070] Fig. 1 illustrates an embodiment of an electronic device 10 for determining and providing a ranking, according to their environmental impact, of a plurality of distinct aeronautical flights, according to the present invention.

[0071] The electronic device 10 for determining and providing a ranking, according to their environmental impact, of a plurality of distinct aeronautical flights, comprises firstly, a first set Ei of modules for processing each flight in order to determine the quantity of carbon dioxide equivalent CO^^Ox associated with the total quantity of nitrogen oxides emitted on each of said flights.

[0072] More specifically, this first assembly E includes a first acquisition module 12 configured to obtain a previously determined nitrogen oxide emission index, said index being a discrete variable comprising, depending on the engine of the aircraft suitable for carrying out said flight, four discrete values ​​associated respectively with four distinct flight phases including takeoff, climb, approach, descent.

[0073] This first set Ei also includes, for processing each flight, a second acquisition module 14 configured to obtain, from said index, at least by linear regression, a nitrogen oxide emission model suitable for providing the nitrogen oxide emission index associated with each triplet of input data types including engine thrust, humidity and atmospheric pressure.

[0074] In addition, this first set Eicomprise, to process each flight, a discretization module 16 configured to discretize the trajectory associated with said flight, according to a predetermined constant time step, into a plurality of trajectory segments.

[0075] This first assembly Ei also includes a first determination module 18 configured to determine, for each segment, a triplet of input data including the engine thrust, humidity and atmospheric pressure associated with said segment.

[0076] This first Ei assembly also includes a second determination module 20 configured to determine, for each segment, from said triplet of input data of said segment and said nitrogen oxide emission model, the value of the associated nitrogen oxide emission index.

[0077] The first assembly Ei further includes a third obtaining module 22 configured to obtain, for each segment, the quantity of nitrogen oxides emitted on said segment, using a predetermined fuel flow model, said associated value of the nitrogen oxide emission index and said time step.

[0078] The first assembly Ei also includes a fourth obtaining module 24 configured to obtain the total quantity of nitrogen oxides emitted on said flight, by summing the quantities of nitrogen oxides emitted on each segment of said plurality of segments composing said trajectory of said flight.

[0079] The first assembly Ei further includes a conversion module 26 configured to convert said total quantity of nitrogen oxides into quantity of carbon dioxide equivalent CO^eqNOx^ using a predetermined metric of global warming potential (GWP).

[0080] The first assembly Ei also includes a third determination module 28 configured to determine, at least from said quantity of carbon dioxide equivalent CC^eqNOx associated with the total quantity of nitrogen oxides emitted on each flight, an environmental impact score C for each flight.

[0081] As illustrated by [Fig.1], as an optional complement, the electronic device 10 for determining and providing a ranking, according to their environmental impact, of a plurality of distinct aeronautical flights, also includes, a second set E2 of modules for determining, for each flight of said plurality, the equivalent carbon dioxide impact associated with at least one persistent condensation trail of said flight, so that it is also taken into account in determining said environmental impact score C of said flight.

[0082] In other words, when this optional complement is implemented, the output of said second set E2, namely, for each flight of the plurality, the equivalent carbon dioxide impact associated with at least one persistent condensation trail of said flight is transmitted as input to the third module 28 for determining an environmental impact score C for each flight.

[0083] According to one variant, illustrated by [Fig.1], of this optional supplement, said second E2 assembly includes first of all a fifth acquisition module 30 configured to obtain, as input, a map of the geographical areas of formation of persistent condensation trails of said flight.

[0084] According to this variant, said second assembly E2 also includes a module 32 for superimposing said mapping with the trajectory of said flight and for determining the length of persistent condensation trail(s) likely to be generated during said flight.

[0085] According to this variant, said second assembly E2 further comprises a sixth module 34 for obtaining the quantity of carbon dioxide equivalent CO^ cmttrails associated with at least one length of persistent condensation trail of said flight.

[0086] As illustrated by Figure 1, as an optional complement, the electronic device 10 for determining and providing a ranking, according to their environmental impact, of a plurality of distinct aeronautical flights, also includes a seventh module 36 for obtaining a coefficient coef fATC representative of the difficulty of modifying said flight from the point of view of air traffic control, and / or an eighth module 38 for obtaining a coefficient coef' / ajrline representative of the difficulty of modifying said flight from the point of view of the airline associated with said flight.

[0087] In other words, when this optional supplement is implemented, the output of said seventh acquisition module 36, namely, for each flight in the plurality, the coefficient coef f ATC representing the difficulty of modifying said flight from an air traffic control point of view, and / or the output of said eighth acquisition module 38, namely, for each flight in the plurality, the coefficient representing the difficulty of modify said flight from the point of view of the airline associated with said flight, is or are transmitted as input to the third module 28 for determining an environmental impact score C for each flight.

[0088] When the third module 28 for determining an environmental impact score C for each flight is used in its most basic form, said third module 28 for determining an environmental impact score C for each flight is then suitable for using an equation in the following form:

[0089] r v< — c'a ref cil y pairs

[0090] where CO^q ref citypairs cst 'a average of the non-CY92 environmental impact, in terms of nitrogen oxide emissions, of the flights for each pair formed by the departure airport and the arrival airport of said flight.

[0091] When, in an improved manner, the input of said third module 28 for determining an environmental impact score C for each flight is linked to the output of the second set E2, and to the output of the aforementioned modules 36 and 38, said third module 28 of determining an environmental impact score (C) for each flight is then specific to use an equation in the following form:

[0092] c eontritils+ NOx ref cily pairs ) *coefficient ATC COef f airiifft.

[0093] where CO^eg ref citypairs cst 'a average of the non-CO2 environmental impact, in terms of emissions of nitrogen oxides and persistent contrails, of flights for each pair formed by the departure airport and the arrival airport of said flight

[0094] Thus, according to this optional supplement, as among the non-CO2 effects contrails and emissions of nitrogen oxides NOx are the cause of the majority of the "non-CO2" consequences and because their knowledge is sufficiently mature so as not to have too much uncertainty in the results, it is proposed to focus on these two non-CO2 effects to have a relevant view of the non-CZL emissions of a flight.

[0095] Optionally, said third module 28 for determining an environmental impact score C for each flight is also suitable for taking into account the CO2 emissions associated with each flight using an equation of the following form: tOOQbl / CO^+CO^ , „ + CO^eaNOx ​​\ LOUVOJ | - teq contrails » C - en------Tirâ-------- vcoe / ft*coef f. ,. \ ^-'^2 ref citypairs™-'"^ rcf citypairs f J ATC J OtrllfW

[0097] where CO' ref dtypairs cst 'a average of the CO2 environmental impact of flights for each pair formed by the departure airport and the arrival airport of said flight.

[0098] Regardless of whether or not the aforementioned optional additions are taken into account, the electronic device 10 according to the present invention includes a fourth determination module 40 configured to determine and provide a ranking, according to their environmental impact, of said plurality of distinct aeronautical flights, ranked by decreasing value of said environmental impact score C of each of said flights.

[0099] Said fourth determination module 40 is in particular suitable for providing said classification by display on a screen of the electronic device 10, by sound reproduction, or by transmission to another reproduction device or system such as that of an air traffic control tower or that of an airline.

[0100] Optionally, the electronic device 10 also includes a module 42 for identifying the segment(s) of the trajectory exhibiting the maximum quantity(ies) of non-C emission <?2, ou présentant la ou les quantité(s) maximale(s) d’émission CO2 et non-CO2.

[0101] In the example of [Fig.1], the electronic device 10 for determining and providing a classification includes an information processing unit 44 formed for example of a memory 46 and a processor 48 associated with the memory 46.

[0102] In the example of [Fig.1], the first acquisition module 12, the second acquisition module 14, the discretization module 16, the first determination module 18, the second determination module 20, the third acquisition module 22, the fourth acquisition module 24, the conversion module 26, the third determination module 28, the fourth determination module 40, as well as, as an optional complement, the fifth acquisition module 30, the superposition module 32, the sixth acquisition module 34, the seventh acquisition module 36, the eighth acquisition module 38 and the identification module 42, are each implemented in the form of a software program, or a software component, executable by the processor 48.The memory 46 of the electronic device 10 for determining and providing a classification is then capable of storing a first generation software, a second generation software, a discretization software, a first generation software, a second generation software, a third generation software, a fourth generation software, a conversion software, a third generation software, a fourth generation software, as well as, optionally, a fifth generation software, a superposition software, a sixth generation software, a seventh generation software, an eighth generation software, and an identification software. The processor is then capable of executing each of the aforementioned software.

[0103] In an alternative not shown, the first obtaining module 12, the second obtaining module 14, the discretization module 16, the first determination module 18, the second determination module 20, the third obtaining module 22, the fourth obtaining module 24, the conversion module 26, the third determination module 28, the fourth determination module 40, and optionally the fifth obtaining module 30, the superposition module 32, the sixth obtaining module 34, the seventh obtaining module 36, the eighth obtaining module 38 and the identification module 42, are each implemented as a programmable logic component, such as an FPGA (Field Programmable Gate Array) or an integrated circuit, such as an ASIC (Application Specified Integrated Circuit).

[0104] When the electronic device 10 for determining and providing a classification is implemented in the form of one or more software programs, i.e., in the form of a computer program, also called a computer program product, it is further capable of being stored on a computer-readable medium, not shown. The computer-readable medium is, for example, a medium capable of storing electronic instructions and to be connected to a computer system bus. For example, the readable medium is an optical disc, a magneto-optical disc, ROM, RAM, any type of non-volatile memory (e.g., FLASH or NVRAM), or a magnetic card. A computer program containing software instructions is then stored on the readable medium.

[0105] An example of the operation of said electronic device 10 for determining and providing a classification, according to their environmental impact, of a plurality of distinct aeronautical flights is now described below in relation to [Fig.2].

[0106] More specifically, it is hereafter considered that, according to the present invention, the method 50 for determining and providing a classification, according to their environmental impact, is implemented for a plurality of distinct aeronautical flights comprising M distinct flights with M>2, each flight being identified by an index j such that l <j<M.

[0107] Said process 50 is therefore partly iterative, the majority of its steps being repeated for each flight of index j.

[0108] According to a step 52, j is initialized to one and the flight with index j=l of the plurality of M distinct aeronautical flights is first dealt with.

[0109] To process this flight with index j=l, a first step 54 of obtaining OBT_I, a previously determined nitrogen oxide emission index, is implemented. Said index is a discrete variable comprising, as a function of the engine of the aircraft performing said flight, four discrete values ​​associated respectively with four distinct flight phases including takeoff, climb, approach, descent.

[0110] For this purpose, it is suggested, for example, to use the "VICAO Aircraft Engine Emissions Databank" established in June 2023 and published by the International Civil Aviation Organization (ICAO). This freely accessible database contains the results of engine emission certification tests. These tests are carried out under four test conditions: take-off, climb out, approach, and idle. These four test conditions are described in Chapter III of the "ICAO Environmental Report 2022". They correspond to thrust ratings based on maximum thrust.

[0111] Next, from said index, at least by linear regression, a step 56 of obtaining OBT_MOD of a nitrogen oxide emission model is implemented, said nitrogen oxide emission model being suitable for providing the nitrogen oxide emission index EINOxr associated with each triplet of input data types including engine thrust, humidity and atmospheric pressure.

[0112] In other words, this step aims to enrich the current and partial knowledge of EINOx (only four points for each engine model) in order to generalize it to build an emission model capable of giving an approximation of EINOx under all conditions.

[0113] On the one hand, as explained previously, the classic EINOx depends on the type of motors as well as its operating conditions.

[0114] Here, according to the present invention, it is advantageously proposed, in a non-obvious manner, to represent the load demanded of a motor by the thrust setpoint. Since each test condition corresponds to a percentage of maximum thrust, it is then possible to determine an empirical relationship between the thrust and EINOx by performing a linear regression for each motor model from the four points (thrust, EINOx) known and obtained in the preceding step 54.

[0115] On each of the linear regressions performed according to the present invention on the 465 engine models contained in the document (i.e. database) of "VICAO Aircraft Engine Emissions Databank" cited above, an average error of 2.21 ______ is obtained, which corresponds to an average error of NOX & fuel consumed 13% is very satisfactory considering the difficulty of having precise knowledge of EINOx.

[0116] Furthermore, the EINOx also depends on the atmospheric conditions in which the aircraft operates. The present invention also proposes, within the 1CAO Aircraft Engine Emissions Databank database, to access the minimum and maximum atmospheric pressure as well as the minimum and maximum humidity measured during each test, in order to apply, specifically according to the present invention, an altitude and humidity correction to get as close as possible to the actual EINOx in flight.

[0117] For such a correction, it is proposed in particular to apply the teaching of D. Alejandro Block Novelo et al. indicated in the document entitled "On-board compressor water injection for civil aircraft emission reductions: Range performance with fuel burn analysis" of February 2019, and in particular equation (6) of this document to correct the EINOx taking into account meteorological conditions.

[0118] It should be noted, however, that the correction disclosed by D. Alejandro Block Novelo et al. is applied in the aforementioned document using an emission index calculated from the temperature inside the compressor, whereas the present invention proposes to apply this correction to the emission model obtained by linear regression, which is suitable for providing an approximation EINOxr of EINOx under all conditions. According to the present invention, for such a correction, the average between the minimum measurement is taken as the reference meteorological conditions. and maximum humidity and pressure for each test (i.e. for each of the 465 engine models contained in the ICAO Aircraft Engine Emissions Databank).

[0119] In parallel, previously, or, as illustrated by [Fig. 2], successively to the aforementioned steps 54 and 56, a discretization step 58 of the trajectory Tvj associated with said flight of index j, into a plurality of trajectory segments, is implemented at a constant time step from one flight to the next, predetermined. For example, said plurality comprises N segments with N>2, each segment being identified by an index i such that l <i<n.

[0120] Thus, to determine the quantity of carbon dioxide equivalent CO^eqNOx associated with the total quantity of nitrogen oxides emitted on each of said flights, the method according to the present invention comprises a second iteration loop of index i of trajectory segment nested in the first iteration loop of index j of each flight of said plurality of flights to be classified.

[0121] For each segment, the method 50 includes a step 60 of initializing the index i to one, followed by a step 62 of determining (i.e. predicting) DET_TS; of a triplet of input data comprising the engine thrust, humidity and atmospheric pressure associated with said segment of the trajectory of said flight of index j. In other words, this triplet of predicted data corresponds to the meteorological conditions that are predicted for the flight (in particular via weather models) as well as the engine thrust, associated with the segment of the flight considered, and determined from the trajectory using an existing aircraft model.

[0122] As an optional complement, said triplet of input data of said segment is also determined from a previously determined test data set 63 (also called database BD).

[0123] For example, database 63 includes at least the data from the aforementioned document "ICAO Aircraft Engine Emissions Databank" established in June 2023 published by the International Civil Aviation Organization (ICAO) which groups together the results of engine emission certification tests and contains the so-called reference weather conditions, because they were encountered during these tests.

[0124] Thus, according to this optional supplement, during step 62 of the DET_TS determination; of a triplet of input data including the engine thrust, humidity and atmospheric pressure associated with said segment of the trajectory of said flight of index j, it is proposed to access the average meteorological data on each trajectory segment to implement an altitude and humidity correction carried out by comparing the predicted flight data with the meteorological conditions measured during the test.

[0125] From said triplet of input data of said segment and of said nitrogen oxide emission model, the process further includes, for each segment, a step 64 of determination D_VS; of the value of the associated nitrogen oxide emission index.

[0126] Then, using a predetermined fuel flow model, said associated value of the nitrogen oxide emission index and said time step, the process 50 includes a step 66 of obtaining D_QS; (i.e. determination) of the quantity of nitrogen oxides emitted on said segment.

[0127] According to one embodiment, the predetermined fuel flow model used according to the present invention is, for example, the "Poll-Schumann" model, which allows the average thrust and fuel flow rate to be determined on each segment. By combining this information with the associated value of the nitrogen oxide emission index, called EINOX (Thrust, Humidity, Pressure), and the time step, it is then possible to deduce the quantity QSi^ox of NOx emitted on each segment of the discretized trajectory, in particular according to the following equation:

[0128] = EINOX {Thrust, humidity, pressure}*Fuel Flow^No time

[0129] Following the aforementioned steps 62, 64, 66, according to a step 68, the index i is incremented.

[0130] A test step 70 is then implemented to determine whether or not All N segments of the considered flight trajectory have been processed.

[0131] If not, according to arrow 72, the aforementioned steps 62, 64 and 66 are repeated.

[0132] If so, according to arrow 74, the process then includes a step 76 of obtaining D_Qt of the total quantity of nitrogen oxides emitted on said flight, by summing the quantities of nitrogen oxides emitted on each segment of said plurality of segments composing said trajectory of said flight.

[0133] Then, according to a step 78, the process 50 includes the CONV conversion of said total quantity of nitrogen oxides into quantity of carbon dioxide equivalent CO^q^ox^ using a predetermined metric of global warming potential.

[0134] As an optional complement, said predetermined global warming potential metric is GWP100, as introduced in the 2021 study by Lee et al entitled "the contribution of global aviation to anthropogenic climate forcing for 2000 to 2018" which provides access to coefficients allowing to translate an emission on the scale of CO2 these coefficients being called GWP, the GWP100 applying over a period of 100 years which corresponds to the order of magnitude of the lifetime of CO2.

[0135] Regarding the choice of metrics, there is currently no consensus in the scientific community on comparing non-CD2 emissions with their different lifetimes and CO2. According to this optional supplement, it is proposed to choose GWP100 (Global Warming Potential), which is indeed currently This is currently the most mature metric and allows for the comparison of emissions with different lifetimes, which is crucial when considering non-CO2 effects. Furthermore, this metric has the advantage of allowing these impacts to be expressed in terms of CO2 by establishing a "CO2 equivalence," that is, expressing an emission in terms of the quantity of CO2 that would induce the same consequences.

[0136] By using GWP100, the process according to the present invention gains credibility since GWP100 is a reference metric widely used in particular in climate policies (notably by the Kyoto Protocol).

[0137] More specifically, said conversion 78 corresponds to the multiplication of said total quantity of nitrogen oxides obtained at the end of step 76 by multiplying it by the GWP100 constant associated with nitrogen oxide emissions indicated in the aforementioned study by Lee et al of 2021.

[0138] Next, at least from said quantity of carbon dioxide equivalent CO^q^ox associated with the total quantity of nitrogen oxides emitted on said flight, the process includes a step 80 of determining D_C an environmental impact score C of said flight.

[0139] According to a first variant, in its most basic form, the said environmental impact score C of each flight is determined using the equation in the following form:

[0140] r co^nox V "" CCK ref cayjuars

[0141] where CO^f ref eitypairs is the average non-CO2 environmental impact, in terms of nitrogen oxide emissions, of flights for each pair formed by the departure and arrival airports of said flight. This coefficient CO^f ref eitypairs is defined by statistical analysis from a database of completed flights. This coefficient CO^f ref eitypairs allows for the comparison (via the C score) of flights of different types by normalizing the C score by the emissions that are emitted on that route on a recurring basis. Without dividing by this coefficient (i.e., without normalizing), a Paris-New York flight would often be found to be more problematic than a Toulouse-Paris flight since more emissions will occur on the former (longer route with a different aircraft).

[0142] Other variants of the calculation of the C score will be described later depending on the implementation of optional steps.

[0143] Following the aforementioned steps, according to a step 82, the index j is incremented.

[0144] A test step 84 is then implemented to determine whether or not all N segments of the flight trajectory under consideration have been processed.

[0145] If not, according to arrow 86, the aforementioned steps are repeated.

[0146] If so, according to arrow 88, the determination and provision of classification is implemented as described later.

[0147] Indeed, optionally according to the example embodiment of [Fig.1], as of [Fig.2], in parallel with the aforementioned steps, process 50 also includes the determination of the equivalent carbon dioxide impact associated with at least one persistent contrail of said flight, and taking it into account to determine said environmental impact score of said flight.

[0148] Such a determination includes, for each flight (i.e. first iteration loop of index j of each flight) according to a variant, the optional steps 90, 92 and 94.

[0149] In optional step 90, the process includes obtaining OBT_Z, as input, a map of the geographical areas of formation of persistent condensation trails of said flight.

[0150] Indeed, in order to estimate the environmental impact of persistent contrails, it is essential to quantify the quantity of persistent contrails created. To do this, it is necessary to map the areas conducive to the formation of persistent contrails. These are the areas where an aircraft flying within them has a high probability of creating persistent contrails.

[0151] To this end, there is a certain consensus on locating these areas according to two criteria, namely, on the one hand, the Schmidt-Appleman Criterion (SAC), which makes it possible to determine the humid and cold areas where aircraft can create contrails by condensing water vapor. However, only persistent contrails have a significant impact on global warming; therefore, on the other hand, there is a second criterion, Ice Super-Saturated Regions (ISSR), according to which, for a contrail to persist and have a significant climate impact, it must form in an ice-saturated region. This is characterized by a relative humidity (RHice) in ice greater than 100% (RHjce = 100%, where e represents the water vapor pressure and the pressure of ice saturation).

[0152] According to another example, there are also python libraries for mapping these areas of formation of persistent condensation trails by estimating from weather data the presence or absence of persistent condensation trails such as the PyContrails tool whose output (i.e. indicating the presence or absence of persistent condensation trails) is used as an input for step 90.

[0153] Then, in optional step 92, method 50 comprises superimposing S of said mapping with the trajectory Tvj of said flight of index j considered and determining

[0154]

[0155]

[0156]

[0157]

[0158]

[0159]

[0160]

[0161]

[0162]

[0163]

[0164]

[0165]

[0166] the length of persistent condensation trail(s) likely to be generated during said flight. In optional step 94, process 50 includes obtaining OBT_CONT the quantity 96 of carbon dioxide equivalent CO^q contrails associated with at least one length of persistent condensation trail of said flight of index j, using in particular the coefficient GWP100 expressed according to the length of persistent condensation trail generated to have the impact in carbon dioxide equivalent in v ^leq contrails- According to this option, the quantity 96 of carbon dioxide equivalent CChgq contrails cst then taken into account, as an input, in the aforementioned step 80 of determination D_C of an environmental impact score C of said flight. According to another optional addendum, the aforementioned step 80 for determining D_C an environmental impact score C for said flight also takes into account at least one of the following coefficients: - a coefficient Cf = coeffATC representing the difficulty of modifying said flight from an air traffic control point of view, with Ci between zero and one; - a coefficient C2 — a coefficient representing the difficulty of modifying said flight from the point of view of the airline associated with said flight, with C2 between zero and A. Thus, when such consideration is implemented, in an improved manner, the aforementioned step 80 of determining D_C an environmental impact score C for said flight has the following inputs: - the quantity of carbon dioxide equivalent CO^eqNOx resulting from the conversion step 78; - the amount of carbon dioxide equivalent CO^eq contrails associated with at least one length of persistent condensation trail of said flight from optional stage 94; - the coefficient C] = coeffATC representing the difficulty of modifying said flight from an air traffic control point of view; - the coefficient C2 = coefficient representing the difficulty in modifying said flight from the point of view of the airline associated with said flight; and the determination of an environmental impact score C for each flight is then specific to using an equation in the following form: / COTjKjfMtiritils+i'OleqSiOx \ ,, „ „ ,, „ ~ C = —775---------- ^coef / *coef / . \ '-^leqref citypairs / JJ ATC JJ amine where ref to typicals cst 'a average of the non-CO2 environmental impact of flights for each pair formed by the departure airport and the arrival airport of said flight, the multiplication by the two coefficients e[o,l etcœff ... Amine LJ being likely to reduce the importance of a flight so that it will not be treated as a priority by the airline by appearing later (i.e. ranked lower) in the descending ranking of flights classified according to the C score from the flight with the most environmental impact to the flight with the least impact.

[0167] As an optional addition, the aforementioned step 80 for determining D_C an environmental impact score C for said flight also takes into account two other variables C3 and C4 to account for the CO2 emissions associated with said flight using a

[0168]

[0169] equation in the following form: / COa+CO + COy^a \qx \ ym 1 leqcmitraux i C = 775------------- -"coe f / ,*coe ff . \ ref dty rej citypairs / * Ouch, f affirline where C2 = the CO2 emissions associated with said flight using a coefficient constant multiplier EICO2 = 3A^kg / kg {fixed by the International Civil Aviation Organization (ICAO) such that CO^ — 3,y.) with Qtj the quantity of fuel burned as used in the 1CAO Environmental Report 2022 and in VICAO Carbon Emissions Calculator Methodology.

[0170] c\.Ca=CO^ .. . . is the average of the CO2 environmental impact of flights rej atypairs J r for each pair formed by the departure airport and the arrival airport of said flight.

[0171] Indeed, considering only non-CO2 effects, it is possible to find oneself in a situation where a flight is modified in order to reduce non-CO2 emissions but which in return consumes more fuel, therefore emits more CO2 and which, considering the overall environmental impact, would be worse than the initial trajectory.

[0172] This problematic situation is unfortunately possible, as described by E. Roosenbrand et al. in the document entitled "Contrail minimization through altitude diversions: A feasibility study leveraging global data" of 2023, where it is indicated that in 63% of cases a modification of the trajectory to avoid a contrail zone, the closest solution is to reduce the altitude which leads to a reduction in fuel efficiency and therefore an increase in fuel consumption, CO emissions and potentially NOx.

[0173] Similarly, according to the 2018 study by S. Freeman et al. entitled “Trading off Aircraft Fuel Bum and NOx Emissions for Optimal Climate Policy,” a 20% reduction in nitrogen oxide (NOx) emissions leads to a 2% increase in the amount of CO2 emitted. Therefore, the CO2 / non-CO2 trade-off is essential for more sustainable aviation.

[0174] Thus, by considering a “CO2 equivalence”, the process according to the present invention contributes to anticipating the future problem of the CO2 / non-CO2 effects trade-off, which will be all the more important with the integration of non-CO2 effects into carbon taxation systems, by grouping and comparing several types of non-CO2 emissions (i.e., nitrogen oxide emissions and non-CO2 emissions associated with persistent contrails), and furthermore by integrating operational difficulties via the ATC coefficient and / or airline coefficient.

[0175] It should be noted that according to the aforementioned optional supplement, the choice of GWP100 allows each of the effects considered to be compared: emission of nitrogen oxides NOx, emissions associated with persistent contrails and carbon dioxide CO2 as such, and this over their entire life cycle and therefore to consider their overall impact in order to reduce the ecological footprint of the flight in a global way.

[0176] This choice of GWP100 also makes it possible to directly determine the environmental impact of a flight from the length of persistent condensation trails created and the quantity of nitrogen oxides NOx emitted, as well as to express the "non-CO2" climate impact in a CO2eq term, which is very useful subsequently for the implementation of a CO2 / non-CO2 trade-off since all emissions are "on the same scale".

[0177] At the end of each iteration of the first iteration loop of index j, the score C of each flight of index j is transmitted for storage as input to step 98 of determination and provision of the ranking 99, according to their environmental impact, of the plurality of the M distinct aeronautical flights, the flight having the most significant environmental impact (i.e. the highest score C and therefore the most problematic flight) being ranked first.

[0178] As an optional addition, the method 50 according to the present invention also includes a step 100 for obtaining OBT_Csi the quantity of carbon dioxide equivalent associated with at least one length of persistent contrail of said flight for each segment considered, resulting from the discretization step. Such a quantity per trajectory segment is obtained in particular by superimposing the mapping of the geographical areas of formation of persistent contrails of the flight with each of said segments to determine the length (i.e., the size) of the contrail on each segment considered.

[0179] Said quantity, per segment, of carbon dioxide equivalent associated with at least one length of persistent condensation trail, as well as the quantity, per segment, of nitrogen oxides emitted, are then provided as input to an ID-S identification step 102; of the segment(s) of the trajectory exhibiting the maximum quantity(ies) of non-CO2 emission, or exhibiting the maximum quantity(ies) of CO2 and non-CO2 emission.

[0180] More specifically, for each segment, the quantity of non-CG2 emission is equal to the sum, on the one hand, of the quantity of nitrogen oxides emitted on said segment converted into quantity of carbon dioxide equivalent CO^qNOx^ using said predetermined global warming potential metric and, on the other hand, of the quantity of carbon dioxide equivalent associated with at least one length of persistent condensation trail of said flight for said segment considered.

[0181] To do this, we use, for example, the following equation for each segment:

[0182] CO^is = GW P} QQ^EINOx^Fuel Flow+GWP1 00^^^

[0183] where:

[0184] CO^! S: corresponds to the average emission rate of equivalent carbon dioxide (in kilo per second, kg / s) on each trajectory segment (a segment being a portion of the trajectory discretized according to a constant time step as carried out during step 58);

[0185] GVFPlOOy^ and GJfPlOO^^ are constants fixed by the study of Lee et al of 2021 which allow to compare the importance of a non-CO2 emission with the impact of a CO2 emission;

[0186] EINOxr: the emission index provided by the nitrogen oxide emission model obtained by linear regression and optionally by altitude and humidity correction according to the present invention, i.e. the quantity of nitrogen oxides NOx emitted per quantity of fuel consumed;

[0187] Fuel flow: the rate of fuel consumed determined using a model such as the "Poll-Schumann" model;

[0188] GS: the aircraft's ground speed (from the English Ground Speed), that is to say the aircraft's speed corrected by the wind;

[0189] kontraiis: the indicator function which is "1" when in an area conducive to the formation of persistent contrails and "0" otherwise. This indicator function is determined using the contrail map generated, for example, by the aforementioned PyContrails tool and takes as input the aircraft's position in longitude, latitude, and altitude.

[0190] Optionally, to this quantity of non-CG2 emission specific to each segment is associated the quantity of CO2 emission specific to be emitted during the same trajectory segment considered.

[0191] To do this, we then use, for example, the following equation for each segment:

[0192] COds + COls = 3,\^Fuel Flow + GWP100Na*EINOx*FuelFlow + GWP

[0193] where:

[0194] CO2ls = 3A6*Fuel Flow: corresponds to the average emission rate of carbon dioxide (in kilo per second, kg / s) on each trajectory segment.

[0195] According to this optional supplement, according to step 104, a representation of the flight, in the form of its trajectory segments, is generated in order to allow a user to more easily identify, in particular visually by display on a screen, the flight segments which have the most environmental impact.

[0196] According to the example in [Fig. 2], such a representation is two-dimensional, with altitude on the ordinate 106 and distance traveled on the abscissa 108. The trajectory 110 is represented as a broken line formed by a plurality of segments. In this representation, a color code is used, for example, to represent the most problematic segments in terms of environmental impact. For example, segments P1 are represented in yellow and indicate exceeding a first environmental impact threshold; segments P2 are represented in orange and indicate exceeding a second threshold higher than the first; and segments P3 are represented in red and indicate exceeding a third threshold higher than the second. In other words, segments P3 are the segments identified as the most problematic in terms of environmental impact.

[0197] Thus, the present invention offers a tool, for example to an airline, which would allow it to visualize for each flight the most emitting portions of the trajectory in order to choose to optimize not the whole flight but only the critical portions in order to limit the operational disturbances caused by the modification.

[0198] Figure 3 illustrates the evolution, as a function of traffic density, of the coefficient representative of the difficulty in modifying a flight from an air traffic control point of view, used according to the present invention to participate in the classification of flights, and avoid studying a potential modification of this flight which could not concretely be carried out in flight.

[0199] Indeed, a highly emitting flight may be difficult to modify because it passes through airspaces where traffic is dense, with strict ATC (Air Traffic Control) constraints which makes a change of trajectory impossible.

[0200] More specifically, representation 112 is associated with a coefficient coeff^TC representing the difficulty of modifying said flight from an air traffic control point of view whose value is equal to one, representation 114 is associated with a value between 0 and 1 in a strict manner (i.e. strictly less than one and strictly greater than zero), while representation 116 is associated with a zero value of this coefficient.

[0201] Traffic density is represented using a texture scale 118, with white 120 representing airspace with low traffic density, while the most densely hatched texture 122 represents airspace saturated with traffic.

[0202] In representation 112, the flight considered along the trajectory Ti has its departure Di and its arrival Ab. Representation 112 illustrates that the flight considered takes place in areas where air traffic is not very dense, so that it is associated with a coefficient fATC whose value is equal to one meaning that it is less difficult to modify it from an air traffic control point of view.

[0203] In representation 114, the flight considered along the trajectory T2 has its departure D2 and its arrival A2. Representation 114 illustrates that the flight considered takes place in areas where air traffic is dense in the surroundings, which corresponds to a coefficient value f strictly between 0 and 1.

[0204] Finally, in representation 116, the flight considered along the trajectory T3 has its departure D3 and its arrival A3. Representation 116 illustrates that the flight considered takes place in areas saturated by air traffic, so that it is associated with a coefficient coeffATC whose value is zero, meaning that it is impossible to modify its trajectory from an air traffic control point of view.

[0205] The aforementioned coefficient C2 = coef fu representing the difficulty of modifying said flight from the point of view of the airline associated with said flight is also between 0 and 1 and aims to avoid studying a potential modification of flight trajectory which could not be carried out in flight from the point of view of the airline operating it.

[0206] Indeed, it may be that a highly emitting flight may be difficult to modify because it makes a very short connection at the destination airport (i.e. hub) and that a possible modification of this flight could cause a delay threatening flights or additional traffic costs.

[0207] For example, if C2 - fairline coefficient = 1, this means (i.e., represents) that any delay due to a change in the flight path is not detrimental to the airline. This flight is not involved in any connecting flights and does not carry passengers with high demands (business or first class passengers).

[0208] If 0 < C2 = coef fMi < 1, this means that a possible delay due to a change in the flight may be more or less penalizing for the airline since it could disrupt other flights or damage the airline's image.

[0209] Finally, if C2 = coefficient - 0, this means that any delay due to a flight change is inconceivable because its impact would have serious consequences for the airline. Therefore, the flight must not be changed.

[0210] In other words, the coefficients coef f ATC and coeffairline are used as weighting coefficients to downgrade a flight in the ranking according to criterion C when the modification of its trajectory is not desirable from the point of view of air traffic control ATC or from the point of view of the airline

[0211] The person skilled in the art will understand that the invention is not limited to the embodiments described, nor to the particular examples of the description, the embodiments and variants mentioned above being suitable for combining with each other to generate new embodiments of the invention.

[0212] The present invention thus makes it possible to develop an indicator to identify flights having non-C<92 non-negligible effects, particularly in terms of nitrogen oxide (NOx) emissions, and optionally emissions associated with persistent contrails, and also optionally by integrating possible operational difficulties (for airlines or air traffic controllers), and is upstream of any trajectory optimization as such, in order, like a filter, to allow focusing on another flight by considering nitrogen oxide (NOx) emissions, or even simultaneously with missions associated with persistent contrails, while integrating operational considerations such as the point of view of airlines or air traffic controllers.

[0213] Thus, the present invention proposes a classification to be used to filter, for example, flight plans submitted by an airline, in order to then optimize only the flights for which optimization would be possible and interesting for the environment and optionally for the airline.

[0214] Indeed, the present invention proposes a generic method which groups together the different non-CO2 emissions to have an overall view of the non-CO2 environmental impact of a flight and which makes it possible to identify problematic flights to be dealt with and makes it possible to consider such non-CO2 emissions as equal to CO2 emissions.

[0215] It is therefore proposed to promote the identification of problematic flights prior to their modification to make them more sustainable, which makes it possible to exploit the fact that only a small percentage of flights generate the majority of non-CO emissions from the sector.

[0216] By choosing the predominant effects whose uncertainties are reasonable, the confidence of operators in this indicator is promoted, which is likely to allow the introduction of non-CO2 effects into their considerations.

[0217] In addition, optionally, for each flight, an identification of the problematic portions of the trajectory is proposed according to the present invention to allow optimization of only one or more portions of the flight.

Claims

1. Demands Method (50) for determining and providing a ranking, according to their environmental impact, of a plurality of distinct aeronautical flights, the method (50) being implemented by an electronic device, and comprising at least the following steps: - for each flight of said plurality: - obtaining (54) a previously determined nitrogen oxide emission index, said index being a discrete variable comprising, as a function of the aircraft engine used to carry out said flight, four discrete values ​​associated respectively with four distinct flight phases including takeoff, climb, approach, descent; - from said index, at least by linear regression, obtaining (56) a nitrogen oxide emission model suitable for providing the nitrogen oxide emission index associated with each triplet of input data types including engine thrust, humidity and atmospheric pressure, - discretization (58) of the trajectory associated with said flight, according to a predetermined constant time step, into a plurality of trajectory segments; - for each segment: - determination (62) of a triplet of input data including engine thrust, humidity and atmospheric pressure associated with said segment; - from said triplet of input data of said segment and of said nitrogen oxide emission model, determination (64) of the value of the associated nitrogen oxide emission index; - using a predetermined fuel flow model, said associated value of the nitrogen oxide emission index and said time step, obtaining (66) the quantity of nitrogen oxides emitted on said segment; - obtaining (76) the total quantity of nitrogen oxides emitted on said flight, by summing the quantities of nitrogen oxides emitted on each segment of said plurality of segments composing said trajectory of said flight; - conversion (78) of said total quantity of nitrogen oxides into quantity of carbon dioxide equivalent CO^q^Ox^ using a predetermined metric of global warming potential; - at least from said quantity of carbon dioxide equivalent CO^eqNOx associated with the total quantity of nitrogen oxides emitted on said flight, determination (80) of an environmental impact score C of said flight; - determination (98) and provision of a ranking (99), according to their environmental impact, of said plurality of distinct aeronautical flights, ranked by decreasing value of said environmental impact score C of each of said flights.

2. Method (50) according to claim 1, wherein said predetermined global warming potential metric is GWP100.

3. Method (50) according to claim 1 or 2, wherein said triplet of input data of said segment is determined from a set (63) of previously determined test data.

4. A method (50) according to any one of the preceding claims, further comprising for each flight of said plurality, determining the equivalent carbon dioxide impact associated with at least one persistent contrail of said flight, and taking it into account in determining said environmental impact score of said flight.

5. A method (50) according to claim 4, wherein said determination of the carbon dioxide equivalent impact associated with at least one persistent contrail of said flight comprises: - obtaining (90), as input, a map of the geographical areas of formation of persistent contrails of said flight; - superimposing (92) said map with the trajectory of said flight and determining the length of persistent contrail(s) likely to be generated during said flight; - obtaining (94) the quantity of carbon dioxide equivalent associated with at least one length of persistent contrail of said flight.

6. A method (50) according to any one of the preceding claims, wherein said environmental impact C score of each dessaid flights also takes into account at least one of the following coefficients: - a coefficient representing the difficulty of modifying said flight from an air traffic control point of view; - a coefficient representing the difficulty of modifying said flight from the point of view of the airline associated with said flight.

7. Method (50) according to claim 6, wherein said score C is obtained using an equation in the following form: / C O2rq cmtraUx^ @2eq NOx \ L“\ CO2eqrefcity„airs ) COeJ-! ATCC0€Jj airline where CO^q ref dtypairs cst 'a average of the non-CO2 environmental impact, in terms of nitrogen oxide emissions and persistent condensation trail(s), of the flights for each pair formed by the departure airport and the arrival airport of said flight.

8. Method (50) according to claim 7, wherein said score C also takes into account the CO2 emissions associated with said flight using an equation in the following form: / C- O-fhC & ,» + Vfjv \ c - m -en ^coef f Â*COef f . \ vv*? ref cüypairs'r^--,~'2eq ref eitypairs / AZ C (UFLUW where CO2 ref citypairs cst 'a average of the CO2 environmental impact of the flights for each pair formed by the departure airport and the arrival airport of said flight.

9. A method (50) according to any one of the claims, further comprising, for each flight, or for a predetermined number of top-ranked flights, an identification step (102) of the trajectory segment(s) exhibiting the maximum quantity(ies) of non-CO2 emissions, or exhibiting the maximum quantity(ies) of CO2 and non-CO2 emissions.

10. An electronic device (10) for determining and providing a ranking, according to their environmental impact, of a plurality of distinct aeronautical flights, the device comprising at least: - for each flight of said plurality: - a first acquisition module (12) configured to obtain a previously determined nitrogen oxide emission index, said index being a discrete variable comprising, depending on the engine of the aircraft performing said flight, four values discrete, associated respectively with four distinct phases of flight including takeoff, climb, approach, descent; - a second acquisition module (14) configured to obtain, from said index, at least by linear regression, a nitrogen oxide emission model suitable for providing the nitrogen oxide emission index associated with each triplet of input data types including engine thrust, humidity and atmospheric pressure, - a discretization module (16) configured to discretize the trajectory associated with said flight, according to a predetermined constant time step, into a plurality of trajectory segments; - a first determination module (18) configured to determine, for each segment, a triplet of input data including the engine thrust, humidity and atmospheric pressure associated with said segment; - a second determination module (20) configured to determine, for each segment, from said triplet of input data of said segment and said nitrogen oxide emission model, the value of the associated nitrogen oxide emission index; - a third acquisition module (22) configured to obtain, for each segment, the quantity of nitrogen oxides emitted on said segment, using a predetermined fuel flow model, said associated value of the nitrogen oxide emission index and said time step; - a fourth acquisition module (24) configured to obtain the total quantity of nitrogen oxides emitted on said flight, by summing the quantities of nitrogen oxides emitted on each segment of said plurality of segments composing said trajectory of said flight; - a conversion module (26) configured to convert said total quantity of nitrogen oxides into quantity of carbon dioxide equivalent CO^^Ox, using a predetermined metric of global warming potential; - a third determination module (28) configured to determine, at least from said quantity of carbon dioxide equivalent CO^eqNOx associated with the total quantity of nitrogen oxides emitted on said flight, an environmental impact score C of said flight; - a fourth determination module (40) configured to determine and provide a ranking, according to their environmental impact, of said plurality of distinct aeronautical flights, ranked by decreasing value of said environmental impact score C of each of said flights.

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