Energy management device and method for the descent and approach phases of an aircraft

Abstract

Energy Management Device and Method for the Descent and Approach Phases of an Aircraft. The present invention proposes a method for establishing an effective energy dissipation strategy for the descent and approach phases of an aircraft, in the form of calculating an optimized descent and approach trajectory. This strategy aims to maximize the maintenance of idle speed while minimizing the use of airbrakes through more efficient decelerations. Figure for the abstract: Fig. 3

Description

Title of the invention: Device and method for energy management during the descent and approach phases of an aircraft 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 functionalities or services available on an FMS 100 are provided by various components illustrated in [Fig.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 the entry of geographical elements constituting 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 construct geographical routes and procedures from the data included in the databases (i.e. the 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 device.

[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 the speed.

[0011] The localization module or "LOC NAV Navigation" 170, enables optimal localization of the aircraft 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 display screens, 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 of 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 known anglicism.

[0015] In preparation for the aircraft 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 according to aircraft performance, a profile which 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 is to be considered that such information forms part of the general knowledge of a person skilled in the art. Examples are given in Figure 4 in the Applicant's application FR3012630, the content of which is incorporated in its entirety by reference.

[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 set to 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," over a portion of the descent between the end of cruise where the descent begins (a point 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 segment depends on altitude and airspeed constraints and / or time constraints defined in the descent procedures.

[0021] Generally, 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, consist of flying the aircraft as high as possible above populated areas, maximizing the reduced-thrust sections. Noise reduction is achieved by increasing the altitude of the reference profile and reducing engine noise, and it is therefore necessary to perform the descent at idle (IDLE) as much as possible. Segments with steep gradients that require increased thrust to maintain glide path and airspeed must then be avoided.

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

[0024] Finally, operationally, crews need to control the dissipation of the total aircraft energy during descent, i.e., to 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 constant slope between two constraining 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 leading to excessive CO2 emissions. - Increased and excessive use of air brakes on decelerated segments resulting in cabin discomfort, noise and workload for the crew. - Decelerations that are too long with deceleration rates that are too low, and barely perceptible to the pilot and air traffic control. - An excessively early aircraft configuration which leads to an increase in aerodynamic noise, predominant over engine noise in the landing phases.

[0030] In addition, 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 the 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 IDEE regime is found, although it is theoretically possible to switch back to the IDEE regime under the constraint in question.

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

[0034] The point on the flight plan separating the two types of descent (geometric and IDLE) is called the geometrical path point (GPP). The GPP is a point on the flight plan separating the geometric descent segment The IDLE descent segment metric 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] Citation may be made of the Applicant's French patent FR 3 012 630 B1, 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] Moreover, 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 allows the calculation of a "tailor-made" energy dissipation profile during the 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] An object of the invention is thus to overcome the shortcomings of the prior art by proposing a method for establishing, 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 effective 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 traffic management by ATC for the aircraft landing.

[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 the areas to be adjusted in a manner consistent with actual operations. Thus, the method of the invention makes it possible to determine so-called low energy areas and so-called high energy areas, to advantageously define segments (i.e., slopes) that are to be lowered or raised.

[0047] Thus, in low-energy cases, a constant-speed adjustment makes it possible to maintain a set of segments with sufficient steepness to meet air traffic control requirements while eliminating the use of air brakes as currently required in these cases. Conversely, in high-energy cases, priority is given to the use of air brakes on decelerated segments, in order, on the one hand, to maintain the ability to comply with a speed restriction imposed by air traffic control on constant-speed segments through the use of air brakes, and on the other hand, to meet the operational practices of pilots, who prefer to use air brakes to reduce aircraft speed rather than to maintain speed.

[0048] Advantageously, the method 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 calculating the 4D trajectory, all the elements necessary to The understanding of the vertical strategy, which primarily minimizes the use of engines and airbrakes and reduces deceleration lengths, is 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 to dissipate its 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 an FMS-type flight management system. 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 method implemented by a computer is proposed for managing the energy to be dissipated by an aircraft during the descent and approach phases.

[0056] The method includes steps performed 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 of the process consist of: - determine an initial IDLE flight trajectory in idle engine mode, between an anchor point and the cruise flight level, and evaluate whether all altitude constraints are satisfied for the IDLE trajectory; - if at least one altitude constraint is not satisfied, define a working section between the anchor point and the passage point where the altitude constraint is not satisfied, and determine 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: - evaluate the energy delta required to reach the IDLE trajectory; and - construct an optimized flight profile taking into account the evaluation, the flight profile optimized consisting for said section either of exclusively restoring thrust, or of exclusively using air brakes, while maximizing the distance traveled in IDLE.

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

[0059] According to a 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 together includes steps consisting of determining an angle of the flight trajectory, and performing a backward integration segment by segment, until a condition for verifying that the target constraint has been reached 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 speed of the aircraft 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 consisting of displaying on a cockpit display screen the trajectory obtained by an optimized flight profile.

[0066] According to a 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 for 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 enabling the steps of the process of the invention to be carried out, 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.

[0072] The [Fig.1] already presented, schematically illustrates the structure and functions of an FMS type flight management system allowing the implementation of the device of the invention;

[0073] Figure 2 schematically illustrates an example of implementation of the invention in an FMS;

[0074] Fig. 3 represents in the form of a logic diagram the steps of the process of the invention, in a nominal embodiment;

[0075] Fig. 4 represents in the form of a flowchart a method of implementing the construction step of a "low energy" LE profile;

[0076] Fig. 5 represents in the form of a flowchart a method of implementing the construction step of a "high energy" HE profile;

[0077] Fig. 6 represents in the form of a flowchart a variant of the construction steps of a "high energy" profile according to the process of the invention;

[0078] Fig. 7 illustrates slopes obtained by constructing an HE profile in one embodiment of the invention;

[0079] Figure 8 illustrates the effect of the deceleration rate on altitude. Detailed description of the invention

[0080] In addition to the definitions previously given, the meaning of several acronyms and expressions, either commonly used in the aeronautical field or used in the rest of the description, is now recalled.

[0081] FPA stands for “Flight Path Angle”: angle of the flight path.

[0082] CSTR for "Constraint": constraint.

[0083] CRZ FL for “Cruise Flight Level”: cruising level.

[0084] CAS for "Calibrated Air Speed": conventional speed.

[0085] ISO CAS: conventional constant speed.

[0086] TSP stands for "Too Steep Path": vertical segment too steep.

[0087] MDR stands for "Minimum Deceleration Rate": minimum deceleration rate.

[0088] AP for “Anchor Point”: Anchor Point defined as a point constrained in altitude beyond the final approach, which is identified during a backswing prediction calculation by a flight management system.

[0089] VS stands for "Vertical Speed": vertical speed

[0090] “Backward”: a calculation method performed in reverse or backwards, starting from a point of des- destination and heading back towards a starting point.

[0091] “Forward”: forward calculation mode, starting from a starting point and going towards a destination point.

[0092] GEO for "Geometrical": for example a geometric profile.

[0093] LE for "Low Energy": for example a low or low energy profile.

[0094] HE stands for “High Energy”: for example, a high energy profile.

[0095] AE 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.

[0096] In an embodiment illustrated in [Fig.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.

[0097] In one embodiment, a "state machine" (or "finite automaton") can be used as a sequencer 141. In digital electronics, a finite automaton can be constructed 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 for storing state variables, a combinational logic circuit that determines state transitions, and a combinational logic block that determines the automaton outputs.

[0098] An avionics sequencer here defines a sequence of segments to be used / flyed 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 respecting the flight plan from an initial aircraft state or a predefined strategy linked to the aircraft's different guidance modes.

[0099] 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.

[0100] Figure [Fig.3] represents in the form of a logic diagram the steps of the process of the invention, in a nominal embodiment.

[0101] The process 300 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.

[0102] In a preliminary step 302, the method consists of checking whether the anchor point carries a slope constraint.

[0103] If this is the case, it means that there are no degrees of freedom, and the method allows to construct 314 a GEO geometric profile up to the end of applicability of the slope constraint.

[0104] If the anchor point is not subject to a slope constraint, the method proceeds with a step 304 to initiate an evaluation of an optimized initial trajectory ("IDLE Path") which would be unconstrained by altitude, for an IDLE engine profile. The initial IDLE path contains decelerated and constant-speed flight segments.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] If all altitude constraints are satisfied (branch No), the process allows in a step 308 to check if the cruising level is reached with the profile in IDLE regime.

[0109] If the cruising level is reached, the construction of the "IDLE" profile is maintained and the process ends (branch Yes).

[0110] 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.

[0111] 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 zone between the current anchor point and the passage point where the altitude constraint would be missed.

[0112] In one embodiment, the working area can be adjusted to avoid segments that are too shallow or, conversely, to avoid segments that are too steep.

[0113] Once the work area is defined, the process allows in a subsequent step 312 of determine if there are both decelerated flight segments and constant speed flight segments in this area.

[0114] If there are no co-existences on the working area of ​​decelerated flight segments and constant speed flight segments, the method allows (branch No) in a subsequent step 314 to construct a GEO geometric profile.

[0115] 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 method allows (branch Yes) in a subsequent step 316 to make an evaluation of the energy delta to join the IDLE trajectory from the constrained passing point, in order to verify which energy dissipation strategy can be implemented on the work area.

[0116] Evaluating the energy delta allows for the construction of a flight profile for the working section, which takes into account the result of the evaluation. The flight profile for the section in question may consist of either following gentler gradients, which will lead to increased thrust, or using the airbrakes to follow steeper gradients.

[0117] 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 AE = AEP.

[0118] However, this example is not limiting, and the method can be applied to the kinetic energy Ecet and an evaluation of the delta of kinetic energy AE = AEC.

[0119] In one embodiment, the method can be applied to make an evaluation of the total energy delta, i.e. of the total potential and kinetic energy AE = AEP + AEC.

[0120] After step 316 of evaluating the remaining energy, the process allows in a subsequent step 318 to construct a specific flight profile allowing an energy dissipation adapted 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.

[0121] 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 airfoil), the method allows the construction of an LE airfoil. The LE airfoil 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 4 illustrates one embodiment of the steps for constructing an LE airfoil.

[0122] 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 method allows the construction of an HE profile. The HE profile allows the deceleration segments to be increased first before raising the slope of the constant-speed segments, i.e., installing airbrakes because there is too much energy.

[0123] Figures 5 and 6 illustrate two variants of construction of an HE profile.

[0124] 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.

[0125] After the LE or HE profile construction step, the process allows looping 320 back on a next anchor point, which will be the point representing the next target constraint.

[0126] 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 latter to execute the described steps of the method for calculating a 4D descent and approach trajectory according to the invention.

[0127] 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.

[0128] This refers to a situation where the target point detected by the IDEE evaluation is a missed constraint located below the optimized IDEE trajectory. The resulting profile is then a low-energy profile. Therefore, the objective of the optimized trajectory is to avoid the use of airbrakes on the one hand, and to minimize the use of thrust on the other, without generating excessively shallow segments.

[0129] The solution proposed in the variant of [Fig.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.

[0130] 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-sloping segments (i.e. with a slope less steep than the slope equivalent to the idle regime).

[0131] The method allows a check to be made in 402 to evaluate whether the resulting geometric slope in the working area is too shallow.

[0132] If the slope is too shallow (branch Yes), 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.

[0133] If the slope is sufficiently steep (branch No), the method allows for an evaluation in step 406 to determine, in forward calculation mode from the highest point of the working section, a joining point among those established in the IDEE profile during the initial IDEE evaluation in step 304, and any possible crossing points. The selected joining point meets the objective of minimizing the geometrized parts, in maximizing the stolen parts at idle without additional thrust regeneration.

[0134] The process continues with a step 408 consisting of integrating, based on the initial IDLE evaluation and the selected joining point, a reverse-mode 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.

[0135] The algorithm for constructing a low-energy LE profile terminates and loops back to step 320 of the general process.

[0136] Fig. 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.

[0137] This refers to a situation where the target point detected by the IDLE evaluation is a missed constraint that lies above the optimal IDLE trajectory. The resulting profile is then a high-energy profile, and the use of airbrakes is necessary to follow it.

[0138] 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.

[0139] Advantageously, maintaining the engine speed at idle for as long as possible from the anchor point minimizes noise and fuel consumption at low altitude, while minimizing the use of airbrakes.

[0140] Another advantage of this HE construction is to ensure as much as possible a capacity to absorb a deceleration throughout the profile, for example an ATC speed limitation.

[0141] 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 dive.

[0142] In the case where more drag is required, the air brakes are applied progressively on the segments at constant speed.

[0143] When raising all deceleration segments is not sufficient, air brakes are applied progressively to the constant speed segments.

[0144] According to different embodiments, the application of the air brakes is done either from the upper parts to the lower parts, or from the lower parts to the upper parts.

[0145] Returning to [Fig. 5], if the evaluation indicates that the potential energy delta is positive, the process allows, in a first step 502, the construction of a maximized high-energy profile evaluation (i.e., the most aggressive possible), with an IDLE profile having the maximum permitted air brake ratio, for example 50%.

[0146] This construction remains limited to any binding intermediate altitude constraints that must be respected.

[0147] In a subsequent step 504, the process makes it possible to determine whether or not this profile allows the absorption of the energy delta to be resorbed.

[0148] If this HE max profile does not allow it (branch No), the process allows in 506 to construct a "Too Steep Path" type profile TSP, 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.

[0149] This profile theoretically allows for the absorption of the residual energy delta. This construction is particularly suitable in the case of discontinuities in the flight plane on the lateral plane, which distort the trajectory length and, consequently, the resulting slopes in the vertical plane.

[0150] If the HE max profile allows to absorb more energy than the delta of energy to be absorbed (branch Yes), 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 join the initial IDEE evaluation.

[0151] Then the process continues with a step 510 allowing to determine, in forward calculation mode, intermediate passing points called reference points, from the data obtained in the previous step and data characterizing the performance of the aircraft.

[0152] 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.

[0153] 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 first to the decelerated segments, and then to be applied to the segments at constant speed.

[0154] According to different embodiments, the application of the air brakes is done either from the upper parts to the lower parts, or from the lower parts to the upper parts.

[0155] The algorithm for constructing a high-energy HE profile terminates and loops back to step 320 of the general process.

[0156] Figure 6 represents in the form of a flowchart a variant of the construction steps of a high energy HE profile according to the process of the invention.

[0157] This variant offers a simpler HE profile calculation algorithm, particularly from the point of view of computational performance and software complexity. It allows reduce CPU impact without significantly degrading operational benefits.

[0158] 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 achieving the target constraint is reached in 606.

[0159] 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.

[0160] For this purpose, 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.

[0161] This variant consists of integrating the profile backwards and piecewise, from the last point from the initial IDLE evaluation, located above the geometric slope between the anchor point and the target stress, up to the target stress.

[0162] Each piece of the integration corresponds to a fixed, geometric ground slope, which is contained within a cone.

[0163] In one embodiment the cone is defined by in an upper bound to what the aircraft is capable of flying with a maximum extension of the airbrakes (either on a deceleration segment with a target rate, or on a segment at constant speed); and in a lower bound, to 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).

[0164] Fig. 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.

[0165] 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 energy methods, while considering the aircraft capabilities which are known from its performance database.

[0166] 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 according to the chosen embodiment.

[0167] This type of construction has the advantage of being generic and applies to so-called HE portions as well as to so-called TSP portions.

[0168] In order to limit the number of "Too Steep Path" incidents, which by definition include a vertical discontinuity having operational impacts and a negative impact on pilot workload in particular, the target deceleration rate on the segments decelerated is automatically reduced, which allows the ground slope to be increased by degrading the deceleration rate.

[0169] 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 in 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.

[0170] 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 request the pilot to extend the airbrakes if necessary, and automatically adapts the guidance modes to facilitate reconvergence.

[0171] 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 ensuring the stabilization of the aircraft at 1000 ft AGL.

[0172] 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.

[0173] Fig. 8 is an illustration of the effect of the deceleration rate on altitude.

[0174] In an alternative embodiment, still with the aim of not creating industrial 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 digital integration up to the target constraint; - an estimate of all the slopes successively applicable with regard to the delta of energy to be absorbed; - an overall energy estimate considering the total energy of the aircraft.

[0175] In summary, the present invention enables: - the definition of a tailor-made, optimized and non-geometric descent trajectory with regard to the performance of the aircraft and the context in which it operates (weather conditions and flight plan) allowing to reduce the use of engines, airbrakes, and therefore ultimately a more efficient energy dissipation strategy. - the implementation of specific logics adapted to low energy situations, and high energy situations according to the scenario typology. - displaying context information and actions to be taken by the pilot to comply with the optimized strategy.

[0176] The advantages of the invention are as follows: - a reduction in engine usage. - a reduction in the use of air brakes. - better anticipation and understanding for the pilot of the actions to be taken to effectively dissipate energy depending on the situation encountered. - a facilitation of land / shore exchanges. - improved traffic flow.

Claims

Demands

1. A method (300) implemented by a computer for managing the energy to be dissipated for an aircraft during the descent and approach phases, the method comprising steps executed during a backward calculation of predictions by a flight management system, when a waypoint is identified (302) as an anchor point having altitude constraints but no slope constraints, the steps consisting of: - determining (304) an initial IDLE flight path in idle engine mode, between an anchor point and the cruise flight level, and evaluating (306) whether all altitude constraints are satisfied for the IDLE path;- if at least one altitude constraint is not satisfied, define (310) a working section between the anchor point and the passage point where the altitude constraint is not satisfied, and determine (312) 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 (316) an energy delta to reach the IDLE trajectory; and - construct (318) 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.

2. A method according to claim 1 wherein the evaluation step (316) consists of 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 of constructing a low energy profile consisting of exclusively restoring thrust if the energy delta is negative.

4. Method according to claim 2 wherein 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.

5. A method according to any one of the preceding claims, wherein the step of constructing a flight profile consisting of exclusively deploying airbrakes comprises steps consisting of de- to complete an angle of the flight trajectory, and to perform a backward integration segment by segment, until a condition for verifying that the target constraint has been met is reached.

6. A method according to any one of the preceding claims wherein the step of determining in a working section the decelerated flight segments and the constant speed flight segments, comprises a step of constructing a geometric flight profile if there is not on said working section both at least one decelerated flight segment and one constant speed flight segment.

7. A method according to any one of the preceding claims comprising 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.

8. A method according to any one of the preceding claims comprising further a step of displaying on a cockpit display screen the trajectory obtained by an optimized flight profile.

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

10. Product computer program comprising code instructions enabling the steps of the process according to any one of the process claims 1 to 9 to be carried out 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 one of claims 1 to 9.

12. Aircraft flight management system comprising a device according to claim 11.

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

Images