DEVICE AND METHOD FOR ENERGY MANAGEMENT FOR THE DOWNHILL AND APPROACH PHASE OF AN AIRCRAFT

Description

Technical Field

[0001] The present invention relates to the field of flight management and more specifically to a method of managing the energy of an aircraft during the descent and approach phases. State of the art

[0002] Flight management systems, or flight managers, known by the generic term "Flight Management System" (FMS), offer pilots assistance during flight by providing information on piloting, navigation, estimates, fuel consumption, etc.

[0003] There are different flight management systems whose capabilities and functionalities can vary greatly depending on the aircraft (helicopter, airliner, etc.), its use (civil, military, etc.) and other factors (design era in particular).

[0004] The features or services available on an FMS 100 are provided by various components illustrated on the figure 1 , and generally include a flight plan 110; a lateral trajectory 120; a navigation database 130; predictions 140; a performance database 150; guidance 160; localization 170; a digital data link 180. The pilot has human-machine interfaces (HMIs) allowing him to manage a flight plan, before departure and during navigation.

[0005] The "Flight Plan" module, or FPLN 110, allows you to enter geographical elements that form the skeleton of the route to be followed (departure and arrival procedures, waypoints, routes or airways).

[0006] The lateral trajectory module or TRAJ 120 allows a continuous trajectory to be built from the points of the flight plan, respecting aircraft performance and confinement constraints (RNP).

[0007] The navigation database or NAVDB 130 contains the information to build geographical routes and procedures from the data included in the databases (i.e. waypoints, beacons, segments or legs of interception or altitude...).

[0008] The prediction module or PRED, 140 allows the construction of an optimized vertical profile on a lateral trajectory.

[0009] The performance database, or PERF DB 150, contains the aerodynamic and engine parameters of the aircraft.

[0010] The guidance module or GUID 160 allows the aircraft to be guided in the lateral and vertical planes on its 4D trajectory, while optimizing speed.

[0011] The localization module or "LOC NAV Navigation" 170, allows for optimal aircraft localization based on various radio navigation data sources, provided by positioning systems and sensors, such as GPS, GALILEO, VHF radio beacons, inertial navigation systems.

[0012] The digital data link module or DATALINK, 180 allows communication with control centers and other aircraft.

[0013] From a flight plan, the FMS can calculate a reference trajectory to follow, which is displayed on visual displays, along with an estimate of a set of data likely to be useful to the pilot during the flight, such as the times of passage at the various waypoints on the flight plan, the estimated amount of fuel on board, etc. The results of the calculations performed by an FMS computer, as well as the flight information, are generally rendered on display systems coupled to the FMS to transform the data into readable information.

[0014] The FMS is thus able to control the entirety of a flight, from takeoff to landing, by performing all the necessary calculations, through a flight management computer or "Flight Management Computer" (FMC) according to the well-known anglicism.

[0015] In preparation for the aircraft's landing, an arrival procedure is selected (default approach strategy in the FMS flight management system or strategy chosen by the pilot), and during the descent and approach phases, the FMS calculates an optimized speed and altitude profile based on aircraft performance, a profile that respects all the constraints contained in the selected arrival procedure, while passing laterally through all the waypoints defined in the flight plan.

[0016] Standards govern how flight profiles are calculated during the arrival phase. Although a detailed description of the calculation of typical descent and approach profiles is not provided in this document, it should be considered that such information is part of the general knowledge of a person skilled in the art.

[0017] In summary, it is acceptable to calculate an energy dissipation strategy provided that guarantees are given on vertical excursions, and that they are contained within an acceptable space.

[0018] The trajectory thus obtained constitutes a reference ensuring that the aircraft, if the control system is based on this calculated profile, will arrive in an energy state suitable for landing.

[0019] Flight procedures known as CDA, for "Continuous Descent Approach" according to the established anglicism, aim to descend an aircraft towards a landing runway with reduced engine thrust in order to minimize noise and low-altitude pollution.

[0020] Currently, pilots aim to maintain their descent for as long as possible in an idle thrust regime, known as "idle thrust" or simply "idle." This descent occurs between the end of cruise, where the descent begins (commonly referred to as "Top of Descent" or "ToD"), and a point, as close as possible to the runway, beyond which reduced thrust can no longer be sustained. The length of this idle thrust segment depends on altitude and airspeed constraints and / or time constraints defined in the descent procedures.

[0021] In general, altitude, gradient, speed, or time constraints at waypoints or on the flight plan can be expressed in various ways. Altitude constraints can be of the type "AT" (passage at the point at the given altitude), "AT OR ABOVE" (passage at or above the given altitude), "AT OR BELOW" (passage at or below the altitude), or "WINDOW" (passage between two altitudes). Speed ​​constraints can be of the type "AT" (passage at the point at the given speed), "AT OR ABOVE" (passage at or above the given speed), or "AT OR BELOW" (passage at or below the speed). Time constraints can be of the type "AT" (passage at the point at the given time), "AT OR AFTER" (passage at or after the given time), "AT OR BEFORE" (passage at or before the given time), or "WINDOW" (passage between two times).

[0022] So-called "green" flight procedures, which aim, among other things, to reduce noise and fuel consumption, involve flying the aircraft as high as possible above populated areas, maximizing the periods of reduced thrust. Noise reduction is achieved by increasing the altitude of the reference profile and reducing engine noise, which necessitates performing the descent at idle (IDLE) as much as possible. It is therefore essential to avoid segments with steep gradients that require increased thrust to maintain glide path and airspeed.

[0023] Maintaining idle mode for as long as possible mechanically reduces pollutant emissions because it is the most fuel-efficient mode. This reduction in fuel consumption also fulfills airlines' objectives of reducing operating costs.

[0024] Finally, operationally, crews need to control the dissipation of the total aircraft energy during descent, i.e., control decelerations and altitude losses to arrive with energy compatible with landing at the beginning of the final segment, i.e., a segment aligned with the runway, generally on a slope close to -3°, and often materialized by a radio beam of the "Glide Slope" type.

[0025] A general technical problem with current flight management systems is that they do not allow for the efficient chaining of decelerations and altitude losses constrained by procedures.

[0026] Indeed, the strategy classically applied by state-of-the-art FMS for descents in CDA mode is to fly on a geometric slope between the different altitude constraints in procedure.

[0027] However, the geometric slope is suboptimal for both constant speed segments and decelerated segments.

[0028] Indeed, decelerations are generally not or only slightly effective on segments with a constant slope between two restrictive altitude constraints (i.e. imperative constraints that must be respected by the aircraft).

[0029] In general, this results in the following operational disadvantages: Excessive fuel consumption on constant-speed segments leads to excessive CO2 emissions. Increased and excessive use of airbrakes on decelerating segments results in cabin discomfort, noise, and increased workload for the crew. Decelerations are too long with insufficient deceleration rates, barely perceptible to the pilot and air traffic control. Aircraft configuration is too early, leading to increased aerodynamic noise, which becomes more prominent than engine noise during landing.

[0030] Furthermore, the use of engines or air brakes also increases the aircraft's noise footprint on the ground, which is also undesirable in a context of increasing urbanization near airports.

[0031] The presence of altitude constraints at high altitudes, often combined with speed constraints, is a scenario whose occurrence increases with increasing traffic. This leads current systems to calculate geometric segments up to very high altitudes, close to cruising altitude, severely penalizing the efficiency of aircraft during the arrival phase.

[0032] Indeed, current flight management systems calculate a so-called geometric profile, i.e. with a fixed slope down to the bottom of the flight plan, as soon as an incompatible constraint of an IDLE regime is found, although it is theoretically possible to switch back to the IDLE regime under the constraint in question.

[0033] The descent is then divided into two parts called the "geometric" descent and the "IDLE" descent.

[0034] The point on the flight plan separating the two types of descent (geometric and IDLE) is called the geometric waypoint or "Geometrical Path Point"In English (GPP). The GPP point is a point on the flight plan separating the geometric descent segment from the idle descent segment. It is generally determined by the first binding altitude constraint. This means that from the start of the descent until this GPP point, descent predictions are made at idle engine thrust, and then predictions are calculated using predicted slopes to meet the binding altitude constraints.

[0035] Patent FR 3 012 630 B1 of the Applicant can be cited, which proposes a method for constructing a vertical trajectory designed to optimize aircraft maneuvers during the descent and approach phase of a runway at an arrival airport, by maximizing the number and length of segments flown at reduced thrust that can be integrated into the descent and approach procedure to the landing point. This method has limitations, in particular, it does not take into account the distribution between kinetic energy dissipation and potential energy dissipation.

[0036] Thus, the limitations of known solutions are linked to the fact that the use of engines leads to an increase in fuel consumption and pollutant emissions on the one hand, and on the other hand that the use of air brakes leads to an increase in the workload of the crew.

[0037] Furthermore, known solutions do not take into account the performance of the aircraft as well as the context in which the aircraft operates, thus generating premature wear of the structure, and mechanically increasing maintenance costs.

[0038] Thus, there is no flight management system that can calculate a "tailor-made" energy dissipation profile during descent and approach phases, which is adapted both to the intrinsic performance of the aircraft and to the environmental conditions it encounters.

[0039] The present invention meets the need. Summary of the invention

[0040] One object of the invention is thus to overcome the shortcomings of the prior art by proposing a method to establish, for the descent and approach phases of an aircraft, an effective energy dissipation strategy, in the form of a calculation of an optimized 4D descent and approach trajectory, which aims to maximize the maintenance of the IDLE regime while minimizing the use of airbrakes via more efficient decelerations.

[0041] Advantageously, the invention makes it possible to implement environmentally and economically sustainable flight procedures in the descent and approach phases, and which offer significant advantages in terms of fuel, emissions and noise.

[0042] Generally, the invention consists of calculating and presenting to the crew an energy dissipation strategy to stabilize an aircraft at a certain altitude from its cruising level (1000 ft above the runway level, "AGL" for "Above Ground Level" according to the established anglicism, for example), with an explicit display of the calculation assumptions to optimize the descent and approach, in order to reduce the workload of the crew, and to facilitate decision-making on board, and consequently to simplify and streamline the management of traffic by ATC for the landing of the aircraft.

[0043] In the context of flight procedures known as CDO for "Continuous Descent Operations" according to the established anglicism, and green procedures (aiming at a reduction of noise and pollutants), the implementation of the method of the invention makes it possible to obtain an energy dissipation strategy which serves as a reference for the automatic guidance of the aircraft in order to obtain all the expected benefits.

[0044] The method of the invention allows the calculation of a more efficient 4D descent and approach trajectory, because it takes into account the aircraft's own performance and the context in which it operates (current conditions, procedures and environment).

[0045] The calculated 4D trajectory suggests to the pilot the best strategy to adopt according to the state of the aircraft and the current flight conditions, facilitating understanding on board.

[0046] The invention differs from the prior art by offering a new capability to target areas for adjustment in a manner consistent with actual operations. Thus, the method of the invention makes it possible to determine so-called low-energy zones and so-called high-energy zones, to advantageously define segments (i.e., slopes) that are to be lowered or raised.

[0047] Thus, in low-energy scenarios, a constant-speed adjustment allows for maintaining a set of segments with sufficient steepness to meet air traffic control requirements while eliminating the need for airbrakes, as currently required in these cases. Conversely, in high-energy scenarios, priority is given to using airbrakes on decelerated segments. This is done both to maintain the ability to comply with air traffic control speed restrictions on constant-speed segments through the use of airbrakes, and to accommodate pilot operational practices, which favor using airbrakes to reduce aircraft speed rather than to maintain speed.

[0048] Advantageously, the process according to the invention makes it possible to adjust the distribution of energy dissipation between kinetic energy and potential energy.

[0049] Another advantage of the present invention lies in a division of working sections which makes it possible to avoid the treatment of one section generating in the neighboring section a construction that is too shallow, or conversely too steep.

[0050] Advantageously, after the calculation of the 4D trajectory, all the elements necessary for understanding the vertical strategy, which mainly minimizes the use of engines and airbrakes and reduces deceleration lengths, are presented to the pilot (via HMIs; ND, VD, and MFD screens can be used). The pilot then knows the actions required along the calculated trajectory, which increases their understanding of the aircraft's energy situation and allows them to better anticipate the optimal strategy to implement in order to dissipate their energy.

[0051] Advantageously, the flight management system can automatically adapt the proposed vertical strategy by modifying the aircraft configuration in an optimized way, and / or modifying the speed strategy.

[0052] The invention can preferably be used in conjunction with a Flight Management System (FMS). It can be easily customized to different versions of flight management systems. It can also be implemented on a flight tablet external to a management system, i.e., in a non-avionics system, and operationally coupled with such a flight management system.

[0053] The invention is applicable in any trajectory calculation and prediction present in an FMS or in any means of navigation on board or not managing the trajectory of an aircraft (drone for example).

[0054] The invention can be generalized to all piloted aircraft, in flight or on the ground, and equipped with a trajectory management system.

[0055] To obtain the desired results, a computer-implemented process is proposed for managing the energy to be dissipated by an aircraft during the descent and approach phases.

[0056] The process includes steps executed during a backward calculation of predictions by a flight management system, when a waypoint is identified as an anchor point having altitude constraints but no slope constraints.

[0057] The steps in the process consist of: determine an initial IDLE flight path in idle engine mode, between an anchor point and the cruise flight level, and evaluate whether all altitude constraints are satisfied for the IDLE path; if at least one altitude constraint is not satisfied, define a working section between the anchor point and the waypoint where the altitude constraint is not satisfied, and determine whether in this section there is both one or more decelerated flight segments and one or more constant-speed flight segments; if there is at least one decelerated flight segment and at least one constant-speed flight segment: evaluate an energy delta to reach the IDLE path;and construct an optimized flight profile taking into account the evaluation, the optimized flight profile consisting for said section of either exclusively applying thrust or exclusively using the airbrakes, while maximizing the distance traveled in idle.

[0058] The invention offers several alternative or combined embodiments.

[0059] According to one particular aspect of the invention, the evaluation step consists of determining whether the energy delta is negative or positive.

[0060] According to a particular aspect of the invention, the step of constructing an optimized flight profile consists of constructing a low-energy profile consisting of exclusively restoring thrust if the energy delta is negative.

[0061] According to a particular aspect of the invention, the step of constructing an optimized flight profile consists of constructing a high-energy profile consisting of exclusively using the airbrakes if the energy delta is positive.

[0062] According to a particular aspect of the invention, the step of constructing a flight profile consisting of exclusively putting airbrakes includes steps consisting of determining an angle of the flight trajectory, and performing a backward integration segment by segment, until a condition for verifying the achievement of the target constraint is reached.

[0063] According to a particular aspect of the invention, the step of determining in a working section the decelerated flight segments and the constant speed flight segments includes a step of constructing a geometric flight profile if there is not on said working section at least one decelerated flight segment and one constant speed flight segment.

[0064] According to a particular aspect of the invention, the method includes a step of determining whether the aircraft speed is managed in selected mode and if so, maintaining only the construction of a geometric flight profile.

[0065] According to a particular aspect of the invention, the method further includes a step of displaying on a cockpit display screen the trajectory obtained by an optimized flight profile.

[0066] According to one particular aspect of the invention, the method further comprises a step consisting of defining a new anchor point.

[0067] The invention also relates to a device for managing the energy to be dissipated by an aircraft during the descent and approach phases, the device comprising means for implementing the steps of the process of the invention.

[0068] Another object of the invention is an aircraft flight management system comprising a device according to the invention.

[0069] An object of the invention is also a non-avionics aircraft equipment comprising a device according to the invention.

[0070] The invention also relates to a computer program product comprising code instructions for carrying out the steps of the process of the invention, when said program is executed on a computer. Brief Description of the Drawings

[0071] Other features and advantages of the present invention will become more apparent from the following description in relation to the following drawings. There figure 1 The diagram already presented schematically illustrates the structure and functions of a Flight Management System (FMS) enabling the implementation of the device of the invention; figure 2 schematically illustrates an example of the implementation of the invention in an FMS; The figure 3 represents, in the form of a flowchart, the steps of the process of the invention, in a nominal embodiment; The figure 4 represents, in the form of a flowchart, a method for implementing the construction step of a "low energy" LE profile; The figure 5 represents, in the form of a flowchart, a method for implementing the construction step of a "high energy" HE profile; The figure 6represents, in the form of a flowchart, a variant for implementing the construction steps of a "high-energy" profile according to the process of the invention; The figure 7 illustrates slopes obtained by constructing an HE profile in one embodiment of the invention; The figure 8 illustrates the effect of the deceleration rate on altitude. Detailed description of the invention

[0072] In addition to the definitions previously given, the meaning of several acronyms and expressions, either commonly used in the aeronautical field or used later in the description, is now recalled.

[0073] FPA stands for "Flight Path Angle": the angle of the flight path.

[0074] CSTR stands for "Constraint": constraint.

[0075] CRZ FL stands for "Cruise Flight Level": cruising level.

[0076] CAS stands for "Calibrated Air Speed": conventional speed.

[0077] ISO CAS: conventional constant speed.

[0078] TSP stands for "Too Steep Path": a vertical segment that is too steep.

[0079] MDR stands for "Minimum Deceleration Rate": minimum deceleration rate.

[0080] AP stands for "Anchor Point": Anchor point defined as a constrained point in altitude beyond the final approach, which is identified during a backswing prediction calculation by a flight management system. VS stands for "Vertical Speed": vertical speed

[0081] "Backward": a calculation method that works backwards or in reverse, starting from a destination point and going back towards a starting point.

[0082] “Forward”: calculation mode said to be forward, starting from a starting point and going towards a destination point.

[0083] GEO stands for "Geometrical": for example, a geometric profile.

[0084] LE stands for "Low Energy": for example, a low or low energy profile.

[0085] HE stands for "High Energy": for example, a high energy profile.

[0086] ΔE for an energy delta: total energy difference (kinetic and / or potential) between the endpoint of a profile calculated backwards in Idle thrust from an AP and a constraint in procedure.

[0087] In an embodiment illustrated on the figure 2 The method of the invention is implemented by a sequencer 141 in a prediction module 140 of an FMS 100 or a flight management system having a functional architecture comparable to an FMS, within an aircraft 200. The FMS being generally connected to many computers (several dozen), some can be called upon to implement one or more steps of the calculation of a 4D descent and approach trajectory according to the method of the invention.

[0088] In one embodiment, a "state machine" (Or "finite automaton" " can be used as a sequencer 141. In digital electronics, a finite state machine can be built as a programmable logic circuit, or an industrial programmable logic controller, with logic functions implemented by flip-flops or relays. A hardware implementation generally includes a register to store state variables, a combinational logic circuit that determines state transitions, and a combinational logic block that determines the controller outputs.

[0089] An avionics sequencer defines a sequence of segments to be used / flighted according to a calculated strategy, i.e., defined by logical rules governing sequences of segments. The resulting set of segments constitutes a reference vertical trajectory to which the aircraft will be controlled. Thus, an avionics sequencer assembles, according to predefined rules, different trajectory segments that respect the flight plan, starting from an initial aircraft state or a predefined strategy linked to the aircraft's various guidance modes.

[0090] In an alternative embodiment, the method of the invention is implemented by a sequencer installed on non-avionics equipment such as a flight tablet or electronic flight bag, operationally coupled with a flight management system. An electronic flight bag refers to an EFB (Electronic Flight Bag). More generally, a computer tablet or a removable or portable screen located in the cockpit can be used.

[0091] There figure 3 represents in the form of a flowchart the steps of the process of the invention, in a nominal embodiment.

[0092] The 300 process is initialized during an FMS prediction calculation, more precisely during a "backward" profile calculation, at each time a constrained altitude point beyond the final approach, or AP anchor point, is reached.

[0093] In a preliminary step 302, the process consists of checking whether the anchor point carries a slope constraint.

[0094] If this is the case, it means that there are no degrees of freedom, and the process allows us to construct a GEO geometric profile up to the end of applicability of the slope constraint.

[0095] If the anchor point is not subject to a slope constraint, the process proceeds with step 304, which initiates an evaluation of an optimized initial trajectory ("IDLE Path") that would be unconstrained by altitude, for an IDLE engine profile. The initial IDLE path contains decelerated and constant-speed flight segments.

[0096] In one embodiment, method 300 is applied only in the case where the speed is managed in managed mode, and includes a step of determining whether the aircraft speed is managed in selected mode or in managed mode.

[0097] In the case where the speed is already managed in selected mode or returns to selected mode, the process is established or re-established on an approach with the automatic construction of a geometric flight profile according to step 314.

[0098] After step 304, the process in a subsequent step 306 makes it possible to evaluate whether all the altitude constraints are satisfied for the initial IDLE trajectory, and therefore to determine whether at least one of the altitude constraints between the current flight point and the anchor point is not satisfied.

[0099] If all altitude constraints are satisfied (No branch), the process allows in a step 308 to verify if the cruising level is reached with the profile in IDLE regime.

[0100] If the cruising level is reached, the construction of the "IDLE" profile is maintained and the process ends (Yes branch).

[0101] If the cruising level is not reached with the "IDLE" profile, the process allows looping back to a new anchor point (step 320) and starting again from the preliminary step 302.

[0102] Returning to step 306, if at least one of the altitude constraints is not satisfied for the optimized IDLE trajectory (Yes branch), the process allows in a subsequent step 310 to define a calculation section or working area between the current anchor point and the passage point where the altitude constraint would be missed.

[0103] In one embodiment, the work area can be adjusted to avoid segments that are too shallow or, conversely, to avoid segments that are too steep.

[0104] Once the working area is defined, the process allows in a subsequent step 312 to determine whether there are both decelerated flight segments and constant speed flight segments in this area.

[0105] If there are no co-existences on the working area of ​​decelerated flight segments and constant speed flight segments, the process allows (branch No) in a subsequent step 314 to construct a GEO geometric profile.

[0106] If on the work area it is determined that there is both at least one decelerated flight segment and at least one constant speed flight segment, the process allows (branch Yes) in a subsequent step 316 to make an evaluation of the energy delta to join the IDLE trajectory from the constrained waypoint, in order to verify which energy dissipation strategy can be implemented on the work area.

[0107] Evaluating the energy delta allows for the construction of a flight profile for the working section, taking into account the evaluation result. The flight profile for the section in question may consist of either following gentler gradients, which will lead to increased thrust, or using airbrakes to follow steeper gradients.

[0108] In one embodiment, corresponding to the present description of an example taken to facilitate understanding of the principles of the invention, the process is implemented by considering only the potential energy EP and the evaluation is made with respect to the potential energy delta ΔE = ΔE P.

[0109] However, this example is not limiting, and the process can be applied to kinetic energy EC and an evaluation of the kinetic energy delta ΔE = ΔE C.

[0110] In an alternative embodiment, the process can be applied to make an evaluation of the total energy delta, i.e. of the total potential and kinetic energy ΔE = ΔE P + ΔE C .

[0111] After step 316 of evaluating the remaining energy, the process allows in a subsequent step 318 to construct a specific flight profile allowing an adapted energy dissipation according to the result of the evaluation, the flight profile being able to be a LE profile said to be low energy or a HE profile said to be high energy.

[0112] If the evaluation indicates that the potential energy delta is negative (i.e., the missed stress is below the flight path provided by the initial IDLE profile), the process allows the construction of an LE profile. The LE profile allows the segments to be lowered at a constant speed while maintaining them at a sufficient level, i.e., restoring thrust or energy without the slope being too shallow. figure 4illustrates a method of carrying out the steps to build an LE profile.

[0113] If the evaluation indicates that the potential energy delta is positive (i.e., the missed stress is above the flight path provided by the initial IDLE profile), the process allows for the construction of a HE profile. The HE profile allows for prioritizing the increase in deceleration segments before raising the gradient of those at constant speed, i.e., installing airbrakes because there is too much energy.

[0114] THE Figures 5 And 6 illustrate two variants of HE profile construction.

[0115] Step 318 of constructing an LE or HE profile provides a reference profile between the anchor point and the point of passage of the targeted missed stress.

[0116] After the LE or HE profile construction step, the process allows looping 320 to a next anchor point, which will be the point representing the next target constraint.

[0117] The method of the invention can be implemented in the form of a program comprising non-transient code instructions which, when the program is executed by a processor, cause the processor to execute the described steps of the method for calculating a 4D descent and approach trajectory according to the invention.

[0118] There figure 4 represents in the form of a flowchart the steps of construction of a low energy LE profile, in an embodiment of the process of the invention.

[0119] This situation arises when the target point detected by the IDLE evaluation is a missed constraint located below the optimized IDLE trajectory. The resulting profile is therefore a low-energy profile. Consequently, the objective of the optimized trajectory is to avoid the use of airbrakes on the one hand, and to minimize thrust usage on the other, without creating excessively shallow flight segments.

[0120] The solution proposed in the variant of the figure 4 consists of maintaining the idle speed from the anchor point for as long as possible in order to minimize fuel consumption and noise at low altitude.

[0121] And on the part adapted to respect the target point, the proposed solution consists of all deceleration being carried out on a set of slopes equivalent to the slope of the idle regime, avoiding the low-slope segments (i.e. with a slope less steep than the slope equivalent to the idle regime).

[0122] The process allows for a 402 check to be performed to assess whether the resulting geometric slope in the work area is too shallow.

[0123] If the slope is too shallow (Yes branch), the process allows in a subsequent step 404 the construction of a GEO flight profile, in order to avoid segments that are too shallow which could hinder pilots and air traffic controllers due to rates of descent that are too low in operations, while generating excessive excursions contrary to the standards in force.

[0124] If the slope is sufficiently steep (branch No), the process allows for an evaluation in 406 to determine, in forward calculation mode from the highest point of the working section, a joining point from among those established in the IDLE profile during the initial IDLE evaluation in 304, and any potential crossing points. The selected joining point meets the objective of minimizing the geometrized sections, while maximizing the sections flowed under the IDLE regime without additional thrust.

[0125] The process continues with step 408, which, based on the initial IDLE evaluation and the selected joining point, integrates a reverse profile from the anchor point to the target point. The profile is characterized by an IDLE regime up to the joining point, followed by a geometric construction between the joining point and the target point. In this way, the deceleration slopes are maintained, and the constant-speed slopes are adapted to absorb the required energy delta.

[0126] The algorithm for constructing a low-energy LE profile terminates and loops back to step 320 of the general process.

[0127] There figure 5 represents in the form of a flowchart the steps of construction of a high energy HE profile, in a first embodiment of the process of the invention.

[0128] This situation occurs when the target point detected by the IDLE evaluation is a missed constraint located above the optimal IDLE trajectory. The resulting profile is then a high-energy profile, and the use of airbrakes is necessary to follow it.

[0129] The goal of the optimized trajectory is then to use a slow-speed thrust throughout the trajectory while limiting the use of air brakes to the decelerating parts as much as possible, before extending it to the constant-speed segments.

[0130] Advantageously, maintaining the engine at idle speed from the anchor point for as long as possible minimizes noise and fuel consumption at low altitude, while also minimizing the use of airbrakes.

[0131] Another advantage of this HE construction is to ensure as much as possible an ability to absorb deceleration throughout the profile, for example an ATC speed restriction.

[0132] Thus the solution consists in the airbrakes being applied progressively at first on the deceleration segments, so as to guarantee a minimum rate of deceleration and that no deceleration will cause the aircraft to nosedive.

[0133] In cases where more drag is required, air brakes are applied progressively over segments at constant speed.

[0134] When raising all deceleration segments is not sufficient, air brakes are applied progressively to the constant speed segments.

[0135] Depending on the different embodiments, the application of air brakes is done either from the upper parts to the lower parts, or from the lower parts to the upper parts.

[0136] Returning to the figure 5 , if the evaluation indicates that the potential energy delta is positive, the process allows in a first step 502 to construct a high energy maximized profile evaluation (i.e. the most aggressive possible), with an IDLE profile having the maximum rate of air brakes allowed, for example 50%.

[0137] This construction remains limited to any potentially restrictive intermediate altitude constraints that must be respected.

[0138] In a subsequent step 504, the process makes it possible to determine whether or not this profile allows the absorption of the delta energy to be resorbed.

[0139] If this HE max profile does not allow it (branch No), the process allows in 506 to construct a "Too Steep Path" TSP type profile, which consists of the assembly of the HE max profile, and a vertical discontinuity at the distance to the destination of the end constraint of the working section.

[0140] This profile theoretically allows for the absorption of the residual energy delta. This construction is particularly suitable in cases of discontinuities in the flight path on the lateral plane, which distort the trajectory length and, consequently, the resulting slopes in the vertical plane.

[0141] If the HE max profile allows to absorb more energy than the delta of energy to be absorbed (Yes branch), the process allows in a subsequent step 508 to determine whether air brakes will be necessary on one or more decelerated segments, and possibly on one or more segments at constant speed, the objective always being to reach the initial IDLE evaluation.

[0142] Then the process continues with a step 510 which allows the determination, in forward calculation mode, of intermediate passage points called reference points, from the data obtained in the previous step and data characterizing the performance of the aircraft.

[0143] These points are then targeted by an integration of the profile from the anchor point to the targeted end point so as to naturally apply air brakes on the desired segments.

[0144] The process continues with a step 512 consisting of integrating a profile in reverse mode, from the anchor point to the target point, the profile allowing air brakes to be applied to the decelerated segments first, then to the segments at constant speed.

[0145] Depending on the different embodiments, the application of air brakes is done either from the upper parts to the lower parts, or from the lower parts to the upper parts.

[0146] The algorithm for constructing a high-energy HE profile ends and loops back to step 320 of the general process.

[0147] There figure 6 represents in the form of a flowchart a variant of the implementation of the construction steps of a high energy HE profile according to the process of the invention.

[0148] This variant offers a simpler HE profile calculation algorithm, particularly in terms of computing performance and software complexity. It reduces CPU impact without significantly impacting operational benefits.

[0149] This generally involves determining, in 602, an angle of the FPA flight trajectory, then performing in 604 a backward integration segment by segment, until a verification condition for reaching the target constraint is reached in 606.

[0150] The backward, segment-by-segment calculation ensures that the trajectory remains locally flyable with the maximum permitted airbrake rate and a minimum deceleration rate when required.

[0151] For this, for each segment, the average slope leading to the target constraint is compared to the maximum flyable slope, and the most constraining is retained while ensuring sufficient use of the airbrakes to avoid unduly "Too Steep Path" incidents.

[0152] This variant consists of integrating the profile backwards and in pieces, from the last point from the initial IDLE evaluation, located above the geometric slope between the anchor point and the target constraint, up to the target constraint.

[0153] Each piece of the integration corresponds to a fixed, geometric ground slope, which is contained within a cone.

[0154] In one embodiment, the cone is defined by an upper bound at what the aircraft is capable of flying with maximum extension of the airbrakes (either on a deceleration segment with a target rate, or on a segment at constant speed); and a lower bound at the geometric slope between the integration start point and the target constraint, itself limited by the IDLE slope (so as not to induce thrust resumption or "Too Steep Path" indus).

[0155] There figure 7 illustrates the construction of an HE profile according to this variant, showing the geometric slope between the current integration point and the target stress, and the steepest slope flyable by the aircraft considering the maximum extension of the airbrakes.

[0156] In order to use the required amount of airbrakes only as needed to limit thrust reductions as much as possible while avoiding the creation of "Too Steep Path", the percentage of airbrakes can be defined by estimates based on geometric or energetic methods, while considering the aircraft's capabilities which are known from its performance database.

[0157] This mechanism is repeated until the target constraint at the top is reached, with a discretization that is given by stopping points that can vary depending on the chosen implementation mode.

[0158] This type of construction has the advantage of being generic and applies to both HE and TSP portions.

[0159] In order to limit the number of "Too Steep Path" which by definition include a vertical discontinuity having operational impacts and a negative impact on the workload of pilots in particular, the target deceleration rate on the decelerated segments is automatically reduced, which makes it possible to increase the ground slope by degrading the deceleration rate.

[0160] The so-called "Too Steep Path" design corresponds to the highest profile and is induced by any altitude constraint that requires being above this path. This profile applies a maximum rate of airbrakes during decelerations and constant-speed sections, and terminates with a vertical discontinuity when it reaches the distance of the constraining constraint. While the resulting altitude profile is therefore discontinuous, the speed profile remains continuous, even when crossing the vertical discontinuity.

[0161] To allow the pilot to anticipate this type of discontinuity, a marker is displayed in the cockpit, on the flight plan page, at the location where the discontinuity is generated. When the discontinuity is reached, the system may prompt the pilot to extend the airbrakes if necessary, and automatically adjusts the guidance modes to facilitate reconvergence.

[0162] The presentation in the cockpit of the trajectory thus obtained, the automatic guidance on this trajectory, and the explicit presentation of the calculation assumptions used (speed change and actuator), through an adapted symbology, allow the pilot(s) to optimize the trajectory while guaranteeing the stabilization of the aircraft at 1000 ft AGL.

[0163] Thus, proposing different slopes for the parts flown at constant speed and the decelerated parts makes it possible to improve the dissipation of kinetic energy, which is currently problematic, while reducing the use of engines and airbrakes.

[0164] There figure 8 is an illustration of the effect of the deceleration rate on altitude.

[0165] In an alternative embodiment, still with the aim of not creating undue TSP, the local use of air brakes on decelerated and / or constant-speed segments, if it is estimated that the altitude difference to be compensated requires it, can, for example, be based on one of the following methods (non-exhaustive list): a numerical integration up to the target constraint; an estimation of all successively applicable slopes with regard to the delta of energy to be absorbed; an overall energy estimation considering the total energy of the aircraft.

[0166] In summary, the present invention enables: The definition of a customized, optimized, and non-geometric descent trajectory, taking into account the aircraft's performance and the context in which it is operating (weather conditions and flight plan), allows for reduced engine and airbrake use, ultimately resulting in a more efficient energy dissipation strategy. This includes the implementation of specific logic adapted to low-energy and high-energy situations, depending on the scenario type. Finally, it displays contextual information and instructions for pilot actions to follow the optimized strategy.

[0167] The advantages of the invention are as follows: Reduced engine usage. Reduced use of airbrakes. Improved anticipation and understanding by the pilot of the actions to take to effectively dissipate energy depending on the situation encountered. Easier ground / aircraft communication. Smoother traffic flow.

Claims

1. Method (300) implemented by a computer for the management of the energy to be dissipated for an aircraft during the descent and approach phases, the method comprising steps executed during a prediction regression calculation by a flight management system, when a waypoint is identified (302) as an anchor point having altitude constraints but no flight path angle constraints, the steps consisting in: - determining (304) an IDLE initial flight trajectory in the idle regime, between an anchor point and the cruising flight level, and evaluating (306) whether all the altitude constraints are satisfied for the IDLE trajectory; - if at least one altitude constraint is not satisfied, defining (310) a work section between the anchor point and the waypoint where the altitude constraint is not satisfied, and determining (312) if in this section, there are both one or more decelerated flight segments and one or more constant-speed flight segments; - if there is at least one decelerated flight segment and at least one constant-speed flight segment: - evaluating (316) an energy delta to join the IDLE trajectory; and - constructing (318) an optimized flight profile taking account of the evaluation, the optimized flight profile consisting for said section either in adding thrust exclusively, or in using the air brakes exclusively, while maximizing the distance traveled in IDLE.

2. Method according to claim 1 wherein the step of evaluating (316) consists in determining whether the energy delta is negative or positive.

3. Method according to claim 2 wherein the step of constructing an optimized flight profile consists in constructing a low energy profile consisting in adding thrust exclusively if the energy delta is negative.

4. Method according to claim 2 wherein the step of constructing an optimized flight profile consists in constructing a high energy profile consisting in using the air brakes exclusively if the energy delta is positive.

5. Method according to any of the preceding claims wherein the step of constructing a flight profile consisting in using air brakes exclusively comprises steps consisting in determining an angle of the flight trajectory, and of making a regression integration segment by segment, until a verification condition that the target constraint has been reached is reached.

6. Method according to any of the preceding claims wherein the step of determining in a work section the decelerated flight segments and the constant-speed flight segment, comprises a step consisting in constructing a geometric flight profile if on said work section both at least one decelerated flight segment and one constant-speed flight segment do not exist.

7. Method according to any of the preceding claims comprising a step consisting in determining if the speed of the aircraft is managed in selected mode and if so maintaining only the construction of a geometric flight profile.

8. Method according to any of the preceding claims further comprising a step consisting in displaying on a display screen of the cockpit, the trajectory obtained by an optimized flight profile.

9. Method according to any one of the preceding claims further comprising a step (320) consisting in defining a new anchor point.

10. Computer program product comprising code instructions making it possible to carry out the steps of the method according to any of method claims 1 to 9, when said program is executed on a computer.

11. Device for managing the energy to be dissipated for an aircraft during the descent and approach phases, the device comprising means for implementing the steps of the method of any of claims 1 to 9.

12. Flight management system for aircraft comprising a device according to claim 11.

13. Non-avionics equipment for aircraft comprising a device according to claim 11.