Method for constructing and controlling a velocity profile including AT or AT or ABOVE velocity constraints.

Abstract

The invention relates to a method for managing speed constraints of an aircraft flight plan, the method comprising the following steps: Identification of an ongoing flight phase; Selection of a CAS speed profile, the speed profile establishing the aircraft's behavior with respect to a speed command; Selection of a Mach strategy, the Mach strategy establishing the aircraft's behavior with respect to a Mach command, the Mach command being a speed command expressed as an equivalent Mach number; Determination of a crossover altitude, the crossover altitude being the altitude at which the aircraft transitions from CAS speed profile control to Mach strategy control; Determination of a criterion for the end of applicability of the speed profile and the Mach strategy. Figure for the abstract: Fig. 1

Description

Title of the invention: Method for constructing and controlling a speed profile comprising AT or AT or ABOVE speed constraints.

[0001] The invention relates to the field of aeronautical navigation and the management of aircraft trajectories. And, more particularly, the invention relates to the construction of a complete flight profile, that is to say from takeoff to landing, comprising a speed profile for the flight of an aircraft, the operation of this profile as well as the means for facilitating the operation of this profile by an operator once the aircraft is in flight. A flight plan is a document, physical or digital, describing the planned flight of an aircraft from its takeoff to its landing and communicated to the air traffic services. This document contains the planned route and the technical characteristics, such as altitude, speed, or even distance, necessary for the smooth running of the aircraft's flight.A speed profile is the result of a calculation including the speed characteristics and allowing the aircraft to be controlled in speed during the different phases which make up the flight.

[0002] Generally speaking, each component of an aircraft is subject to standards imposing specific constraints on it to ensure proper overall operation and therefore the viability of the aircraft. The flight management system (FMS), for example, is subject to specific standards (TSOC-115 for airworthiness, DO283 for RNP functions, ARINC 702A for FMS functions, ARINC 424 for the navigation database containing all the procedures, etc.) requiring it to be capable of managing all types of constraints governing the departure and arrival of an aircraft from or to any airport. Some of these constraints are speed constraints. Among these constraints, some, made mandatory by the new DO283B standard, impose on the aircraft a target speed AT or a minimum speed AT OR ABOVE to be respected at a given point in the flight plan.

[0003] Currently, no known FMS flight management system implements the display and management of this new type of speed constraint, which results in manual management of the situation by the operator.

[0004] Thus, during the complete flight, it may be provided that the aircraft has to respect these particular speed constraints at any given route point, in the CLIMB climb phase, CRUISE cruise flight phase, DESCENT descent phase or APPROACH landing approach phase, constraints defined in a published procedure or imposed for example by an air traffic controller. However, as stated previously, it is not technically not possible in the state of the art to automatically insert such a speed constraint into a usual speed profile determined in the aforementioned manner.

[0005] As presented previously, no known FMS flight management system is currently capable of managing AT OR ABOVE speed constraints. Indeed, only AT OR BELOW constraints or AT constraints are (AT constraints being considered in the same way as AT OR BELOW constraints). In addition, document FR3014213 presents a problem of managing AT or AT OR ABOVE speed constraints. Nevertheless, this document proposes to take into consideration AT or AT OR ABOVE speed constraints only during the DESCENT and APPROACH phases representing the flight phase during which the altitude of the aircraft decreases so as to reach the final landing phase. However, these constraints can also exist during other flight phases.It is therefore appropriate to propose a solution allowing the calculation of a complete and consistent flight profile over all flight phases. In addition, document FR3014213 requires the calculation of a starting point for an acceleration towards a speed constraint in a backward calculation process. The calculation of this type of point is complex in development, therefore presents risks of resumption, requires a longer maturation time, and is costly in terms of response time performance.

[0006] The invention aims to overcome all or part of the problems cited above by proposing a method for managing, calculating and controlling a complete speed profile, for the CLIMB, CRUISE, DESCENT and APPROACH flight phases, taking into account the types of speed constraints AT and AT OR ABOVE.

[0007] Furthermore, the method proposes the definition of speed instructions allowing the aircraft to automatically follow this speed profile, facilitating its operation by a pilot.

[0008] To this end, the invention relates to a method for managing speed constraints of an aircraft flight plan, the method comprising the following steps: - Identification of a flight phase in progress, - Selection of a CAS speed profile, the speed profile establishing the aircraft's behavior in relation to a speed setpoint, - Selection of a Mach strategy, the Mach strategy establishing a behavior of the aircraft in relation to a Mach setpoint, the Mach setpoint being a speed setpoint transcribed into an equivalent Mach number, - Determination of a Cross-Over altitude, the Cross-Over altitude being an altitude of passage from a control of the aircraft according to the CAS speed profile to a control according to the Mach strategy, - Determination of an end criterion for the applicability of the speed profile and the Mach strategy.

[0009] According to one aspect of the invention, the step of selecting the CAS speed profile comprises a step of constructing a first CAS speed profile, the speed setpoint according to the first CAS speed profile being constructed on the basis of the performance of the aircraft.

[0010] According to one aspect of the invention, the step of selecting the CAS speed profile comprises a step of constructing a second CAS speed profile, the speed setpoint according to the second speed profile allowing the aircraft to comply with all of the speed constraints during the flight phase.

[0011] According to one aspect of the invention, the step of selecting the speed profile comprises a step of constructing a third CAS speed profile, the speed setpoint according to the third speed profile being constructed with the knowledge of a predefined target speed of the aircraft and a predefined speed constraint.

[0012] According to one aspect of the invention, the step of selecting the Mach strategy comprises a step of constructing a first Mach strategy, the Mach setpoint according to the first Mach strategy being determined as a function of a predefined Mach.

[0013] According to one aspect of the invention, the step of selecting the Mach strategy comprises a step of constructing a second Mach strategy, the Mach setpoint according to the second Mach strategy allowing the aircraft to comply with all of the speed constraints during the flight phase.

[0014] According to one aspect of the invention, the step of determining a Cross-Over altitude comprises a step of calculating a first Cross-Over altitude, the first Cross-Over altitude being calculated as a function of a first predefined CAS speed constraint, a previously defined CAS speed and a previously defined Mach.

[0015] According to one aspect of the invention, the step of determining a Cross-Over altitude comprises a step of calculating a second Cross-Over altitude, the second Cross-Over altitude being a function of a second predefined CAS speed constraint, an imposed flight level and a previously defined Mach.

[0016] According to one aspect of the invention, the step of determining a Cross-Over altitude comprises a step of calculating a chosen Cross-Over altitude, the chosen Cross-Over altitude being the altitude allowing the aircraft to comply with the CAS speed instruction.

[0017] According to one aspect of the invention, the end of applicability criterion is an end of the flight phase or the reaching of a predefined altitude.

[0018] According to one aspect of the invention, the method for managing speed constraints comprises a step of deleting a speed constraint following the step of determining the end of applicability criterion.

[0019] According to one aspect of the invention, the method for managing speed constraints comprises a step of maintaining an imposed speed of the flight phase.

[0020] According to one aspect of the invention, the method for managing speed constraints comprises a step of monitoring the speed constraints.

[0021] According to one aspect of the invention, the method for managing speed constraints comprises an additional step of adjusting the speed of the aircraft with respect to a first speed constraint of the following flight phase.

[0022] According to one aspect of the invention, the method for managing speed constraints comprises a step of displaying speed constraints during the flight phase.

[0023] The invention also relates to a computer program product, said computer program comprising code instructions for carrying out the steps of the method when said program is executed on a computer.

[0024] The invention will be better understood and other advantages will appear on reading the detailed description of an embodiment given by way of example, a description illustrated by the attached drawing in which:

[0025] [Fig-1] [Fig.l] represents a method for managing speed constraints of a plan of flight of an aircraft according to the invention;

[0026] [Fig.2] [Fig.2] represents a step of selecting a flight profile of the method of management of speed constraints of an aircraft flight plan according to a first embodiment;

[0027] [Fig.3] [Fig.3] is a schematic representation of a resulting velocity profile of the management of speed constraints of a flight plan according to the first embodiment;

[0028] [Fig.4] [Fig.4] represents the step of selecting a flight profile of the method of management of speed constraints of an aircraft flight plan according to a second and a third embodiment;

[0029] [Fig.5] [Fig.5] represents a step of selecting a strategy and a step of determination of a Cross-Over altitude of the speed constraint management process of an aircraft flight plan;

[0030] [Fig.6] [Fig.6] represents additional steps of the management method of speed constraints of an aircraft flight plan;

[0031] For the sake of clarity, the same elements will bear the same references in the different figures.

[0032] The invention presents a management method 1, represented in [Fig.l], of speed constraints of a flight plan of an aircraft capable of proposing a complete flight profile which can be applied to the CLIMB, CRUISE, DESCENT and APPROACH flight phases. The management method 1 according to the invention aims to propose a complete profile to allow the aircraft to fly it automatically and autonomously, and to facilitate the operation of this complete profile by an operator once in flight. The management method 1 is implemented for speed constraints of type AT, representing a speed to be respected, AT OR BELOW representing a maximum speed to be respected or AT OR ABOVE representing a minimum speed to be respected. The management method 1 also allows the consideration of WINDOW type constraints representing a speed window between a minimum speed and a maximum speed as a combination of an AT OR BELOW speed constraint and an AT OR ABOVE speed constraint.

[0033] The method 1 for managing speed constraints of an aircraft flight plan comprises the following steps: - An identification step (05) of a current flight phase of the aircraft, the flight phase can be one of the following phases: CLIMB, CRUISE, DESCENT and APPROACH. - A step of selecting a CAS (Corrected Air Speed) type speed profile 10. The speed profile establishes the aircraft's behavior in relation to a speed setpoint. The speed profile then represents a speed target to be respected by the aircraft at any point in the flight plan according to speed constraints present during the flight phases. - A step of selecting a Mach 20 strategy. The Mach strategy establishes the aircraft's behavior in relation to a Mach setpoint, the Mach setpoint being a speed setpoint transcribed into an equivalent Mach number. Thus, the Mach strategy defines the Mach target to be reached by the aircraft at any point in the flight plan based on the speed constraints present during the flight phases. - A step for determining a Cross-Over altitude 50. The Cross-Over altitude is the altitude at which the aircraft is controlled according to the CAS speed profile and controlled according to the Mach strategy of the speed profile. - A step 30 of determining an end criterion of applicability of the speed profile and the Mach strategy.

[0034] When the speed profile, including the Mach strategy, the Cross-Over altitude and the end of applicability criterion are determined for the current flight phase, the management method 1 identifies the next flight phase in the flight plan and repeats the steps cited previously, namely the steps of selecting a speed profile 10, of selecting a Mach 20 strategy, of determining a Cross-Over altitude Over 50 and determination 30 of an end of applicability criterion for the following flight phase until the entire flight plan of the aircraft is completed, i.e. until the aircraft lands.

[0035] More precisely, the profile of a flight phase of an aircraft conventionally comprises two portions, a first portion where the control setpoint is a CAS speed and a second portion, from a certain altitude called Cross-Over (or XOVER), for which the speed setpoint is a Mach. Thus, the CAS speed setpoint is determined during the construction of the speed profile in order to control the behavior and the speed of the aircraft during the first portion where the control setpoint is linked to a CAS speed. The Mach setpoint is determined during the construction of the Mach strategy in order to control the behavior of the aircraft during the second portion of the flight phase where the control setpoint is linked to a Mach.

[0036] Indeed, from certain altitudes, it becomes necessary to control the speed of the aircraft no longer as a function of a speed in the air (CAS) but from a Mach number, representing the speed of the aircraft in relation to the local speed of sound, which varies according to the temperature. A Mach number then represents a limiting speed at higher altitudes due to the speed of sound and the possible shock waves associated with it which can become an aerodynamic limit to the aircraft. However, this Cross-Over altitude represents a conversion altitude allowing the switch between a control of the CAS speed of the aircraft by means of a speed and a control of the speed of the aircraft by means of a Mach number is called Cross-Over altitude XOVER.

[0037] The Cross-Over altitude XOVER therefore represents the altitude where a specific speed becomes a specific Mach number.

[0038] The step of selecting the speed profile 10 may comprise, as shown in [Fig.2], a step of constructing a first CAS speed profile 100. The speed setpoint according to the first speed profile is then constructed on the basis of the performance of the aircraft. More precisely, the speed setpoint according to the first speed profile is based on the assumption that the speed constraints are compatible with the performance of the aircraft. This first speed profile is then constructed without taking into account the presence of speed constraints of the AT OR AB O VE type, or AT constraints considered for their “minimum speed” aspect and therefore without taking into consideration the presence of these minimum speeds that the aircraft must reach.From then on, the aircraft travels through the flight phase according to the first speed profile which only considers the minimum speed constraints AT OR BELOW which takes the position that these constraints alone are sufficient, the other constraints AT OR ABOVE or AT being automatically respected due to the characteristics and performances of. the aircraft. Once the first speed profile has been constructed, as shown in [Fig. 3], an inventory of these constraints is established. Thus, the aircraft, by following the first speed profile 102, only complies with constraints AT OR BELOW BBB and CCC and deliberately ignores constraints AT OR ABOVE AAA1 and AAA2, deemed to be generated in accordance with the aircraft's performance. Therefore, the speed constraint AT OR ABOVE AAA1, which represents a minimum speed lower than the first calculated speed profile 102, at the level of constraint AAA1, is then complied with. Conversely, the speed constraint AT OR ABOVE AAA2, which is higher than the first speed profile 102 when passing the speed constraint AT OR ABOVE AAA2 of the aircraft following the first speed profile 102, is then not complied with.This information of non-compliance with a speed constraint can then be referred to the operator in order to warn him of this irregularity in maintaining the speeds of the flight phase of the aircraft.

[0039] This irregularity is then explained by a poorly adapted energy ratio between kinetic energy representative of the horizontal acceleration and therefore of the “horizontal” speed of the aircraft and potential energy representative of the vertical acceleration and therefore of the “vertical” speed of the aircraft.

[0040] Therefore, the step of selecting the speed profile 10 can comprise a step of constructing a second CAS speed profile 120, represented in [Fig.4], by adapting the sharing of energy between kinetic and potential. The speed instruction according to the second speed profile then allows the aircraft to respect all of the speed constraints AT and AT or ABOVE and AT or BELOW during the flight phase by modifying the ratio between kinetic energy, namely horizontal speed, and potential energy, namely vertical speed, and by increasing the kinetic energy to the detriment of the potential energy. Thus, the aircraft, by respecting the second speed profile, is then able to gain or lose altitude with a lower vertical gradient.The determination of the modified ratio and the distribution between kinetic energy or horizontal speed and potential energy or vertical speed can be carried out during a step of calculating the modified ratio 124, represented in [Fig.4], by different known methods such as dichotomy, brute force calculation or by means of a numerical estimator. Thus, the second speed profile 120 makes it possible to obtain a flight instruction respecting all the speed constraints, whether they are minimum or maximum.

[0041] Furthermore, the step of selecting the speed profile may comprise a step of constructing a third CAS speed profile 140. The speed setpoint according to the third speed profile is then constructed with the knowledge of a predefined target speed of the aircraft and a predefined speed constraint, the predefined speed constraint being an AT or AT or ABOVE speed constraint. More precisely, The third speed profile is to target an optimal speed called the economic speed of the flight phase ECON. Therefore, speed constraints lower than this economic speed ECON are not considered in the construction of the third speed profile. In addition, only the strongest or most important of the speed constraints AT or AT or ABOVE is studied, that is to say, only the speed constraint imposed on the aircraft describing the highest speed to be reached for the aircraft is considered. If this strongest speed constraint is lower than the economic speed ECON of the flight phase, then the third speed profile only considers the economic speed ECON of the flight phase.

[0042] If the highest speed constraint is greater than the targeted economic speed ECON of the flight phase, then the ratio between the kinetic energy and the potential energy of the aircraft is adapted so as to respect this highest constraint. If the original ratio of the aircraft between horizontal speed and vertical speed makes it possible to satisfy the highest speed constraint, then the latter is taken into consideration for the construction of the third speed profile. The step of constructing the third speed profile 140 can thus comprise a comparison step 142 between the economic speed of the flight phase and the highest speed constraint of the flight phase making it possible to evaluate the taking into account of this highest speed constraint.The step of constructing the third speed profile 140 may also comprise a step of calculating 144 the ratio between kinetic energy or horizontal speed and potential energy or vertical speed of the aircraft making it possible to satisfy the greatest speed constraint if the greatest speed constraint is greater than the economic speed ECON of the aircraft over the flight phase.

[0043] In the case where there is no compatible ratio allowing compliance with the greatest speed constraint while guaranteeing good performance of the aircraft, that is to say without degrading the aircraft itself, the step of constructing the third speed profile 140, by means of the step of calculating 144 the ratio, allows the calculation of a ratio making it possible to get as close as possible to the greatest constraint while respecting the limit flight envelope.

[0044] The step of selecting the Mach 20 strategy makes it possible to provide Mach setpoints in accordance with the speed setpoint previously assigned to the aircraft, namely the first, second or third speed setpoint. The determination step 50 makes it possible, for its part, to determine, as a function of the speed setpoint established during the step of selecting the speed profile 10 and the Mach setpoint established during the step of selecting the Mach 20 strategy for the aircraft, the Cross-Over altitude XOVER between the selected speed setpoint, namely the first, second or third speed setpoint, and the Mach setpoint selected during the step of selecting the Mach 20 strategy.

[0045] Furthermore, the first, second and third speed profiles can be exercised according to a backward calculation method called BACKWARD.

[0046] The BACKWARD method allows, for the DESCENT phase, the calculation of a reverse speed profile, where the speed constraints follow one another starting from the approach speed of the aircraft and accelerating backward from constraint to constraint until the descent start speed. In general, the BACKWARD method presents the calculation of a reference speed profile that the aircraft must follow. The aircraft follows, via the flight management system, a speed profile calculated according to the FORWARD method, in real time, allowing the aircraft, during the DESCENT or APPROACH phase for example, to take into consideration factors external to the aircraft such as real climatic conditions.The flight management method 1 then allows the flight management system to take into consideration the speed indicators as well as the speed levels or constraints generated by the reference, namely the BACKWARD method, and to control the flight plan generated by the FORWARD method on these speed indicators and on the speed levels or constraints for the flight phase. This control is particularly advantageous in the DESCENT or APPROACH phase in order to allow the aircraft to target deceleration points of the aircraft, which can be interpreted as speed indicators to be respected for the aircraft in the flight phase, between each speed constraint so as to shorten the DESCENT or APPROACH phase.

[0047] Thus, the first, second or third speed profile is constructed so as to represent a reverse speed profile. More precisely, the management method 1 allows the construction of the first, second or third reverse speed profile by taking into consideration all of the speed constraints of the flight phase, namely the constraints AT, AT OR ABOVE and AT OR BELOW, and no longer only the speed constraints AT OR BELOW, and particularly those necessary for the speed setpoint such as, for example, the highest speed constraint for the third speed profile.

[0048] Thus, the FMS flight management system of the aircraft generally operating according to a FORWARD calculation method different from the BACKWARD method, the management method 1 also allows the control of this method in favor of the BACKWARD method according to the invention.

[0049] Furthermore, as stated previously, the aircraft may, in certain cases, reach altitudes where the aircraft must be controlled by means of a Mach instruction and not by means of a speed instruction which risks harming the integrity of the aircraft. Therefore, the management method 1 can construct different strategies making it possible to control the aircraft according to a CAS speed instruction or Mach in a given applicability zone.

[0050] Thus, the step of selecting the Mach 20 strategy comprises, as shown in [Fig.5], a step of constructing a first Mach 200 strategy. The Mach setpoint according to the first Mach strategy is determined as a function of a predefined Mach. More precisely, this construction of the first Mach 200 strategy is based on the characteristics and performances of the aircraft since the Mach setpoint according to the first strategy requires compliance with an economic Mach or MACH ECON representing the economic flight Mach of the aircraft. Indeed, the economic Mach corresponds to the speed at which, in the environment where the Mach setpoint prevails, the aircraft exhibits optimized performances by taking into consideration different performance parameters such as the speed of the aircraft or the power deployed in comparison with cost parameters such as the consumption of the aircraft.The constructed Mach setpoint will then respect the economic Mach MACH ECON until the end of applicability criterion determined previously during determination step 30. This first Mach 200 strategy then allows the aircraft to initially respect the speed setpoint defined during step 10 until the Cross-Over altitude XOVER and then to respect as the only setpoint, the economic Mach MACH ECON of the aircraft.

[0051] It should be noted that the first Mach strategy may result in non-compliance with speed constraints after reaching the Cross-Over altitude XOVER allowing the transition from a speed setpoint to a Mach setpoint. Indeed, a constant Mach does not generally mean having a constant CAS speed due to the change in altitude and therefore in temperature and pressure. Nevertheless, this non-compliance may be announced to the aircraft operator who may judge this irregularity as acceptable for the operation of the aircraft.

[0052] Furthermore, the step of selecting the Mach 20 strategy may comprise a step of constructing a second Mach 220 strategy allowing the aircraft to comply with all of the AT and AT or ABOVE speed constraints in the given applicability zone. The Mach setpoint according to the second Mach strategy is then constructed with knowledge of the highest speed constraint. More precisely, the second Mach strategy aims to allow the aircraft to comply with all of the speed constraints in the given applicability zone of the aircraft, in a similar manner to the construction of the second speed profile 120. Therefore, the Mach setpoint corresponds to the highest constraint of the flight phase previously determined in the CAS speed setpoint and controls the aircraft according to this highest CAS speed constraint converted into a Mach number.It should be noted that, in the case where the aircraft is controlled, on the current flight phase, according to the CAS speed setpoint of the third speed profile, the Mach setpoint according to the second Mach strategy can then be a conversion of this speed setpoint. CAS in Mach number. Furthermore, as stated previously, once the Cross-Over XOVER altitude is exceeded, it is no longer possible to control the aircraft's behavior via a CAS speed instruction. The Mach strategy takes precedence over the CAS speed profile by imposing no longer a control of the CAS speed but a control of the aircraft's Mach. However, maintaining a constant Mach after the Cross-Over XOVER altitude, by gaining altitude, leads to a decrease in the aircraft's CAS speed.

[0053] Thus, the step of determining the Cross-Over altitude 50 XOVER allowing the switching of the CAS speed setpoint to the Mach setpoint may comprise, as shown in [Fig.5], a step of calculating a first Cross-Over altitude 520. The first Cross-Over altitude XOVER1 is then calculated as a function of a first CAS speed constraint, which may be, as a preferred example, the highest speed constraint AT or AT or ABOVE, the economic speed ECON of the aircraft and the economic Mach of the aircraft. As an indicative example, the first Cross-Over altitude may be calculated according to the following formula:

[0054] XOVERl e [max(CASm(VP CAS ECON); MACH ECON]

[0055] Where XOVERl represents the first Cross-Over altitude, CAS„MX represents the highest speed constraint, CAS ECON represents the economic speed ECON of the aircraft and MACH ECON represents the economic Mach of the aircraft.

[0056] The step of determining the Cross-Over altitude 50 may also comprise a step of calculating a second altitude, or chosen altitude, of Cross-Over 540 allowing the switching between CAS speed setpoint and Mach setpoint. The second Cross-Over altitude XOVER2 is then the chosen altitude allowing the aircraft to respect the CAS speed setpoint of the speed profile before switching to a Mach setpoint.

[0057] As an indicative example, the second Cross-Over altitude XOVER2 can be calculated according to the following formula:

[0058] XOVERl g [max (CAS„^ CAS ECON); MACH^

[0059] Where XOVERl represents the chosen Cross-Over altitude and MACH2 represents the second Mach strategy.

[0060] Finally, the step of determining the Cross-Over altitude 50 XOVER may comprise a step of calculating a third Cross-Over altitude 560 allowing the switching between CAS speed setpoint and Mach setpoint. The third Cross-Over altitude XOVER3 is then between the altitude of a second predefined AT or AT or ABOVE constraint, which may be, as a preferred example, the highest speed constraint AT or AT or ABOVE, or the altitude of the economic speed ECON if the economic speed ECON is greater than the highest speed constraint AT or AT or ABOVE, and the altitude corresponding to the highest speed between the Mach equivalent to the second CAS speed constraint AT or AT or ABOVE, namely, as a preferred example, highest speed constraint, at an imposed flight level CRZ and the economic Mach ECON MACH.

[0061] As an indicative example, the third Cross-Over altitude XOVER3 can be calculated according to the following formula: [0°62] XOVER3 e [max (CAS^ CAS ECON) ; MACH2crz

[0063] Where MACH, represents the second Mach strategy at flight level CRZ ^CRZ imposed.

[0064] The determination step 30 makes it possible to determine a first end of applicability criterion 320, making it possible to end the CAS speed instruction and the Mach strategy, may correspond to an end of the flight phase, such as for example the end of a CLIMB phase or a CRUISE phase. As a variant, the determination step 30 makes it possible to determine a second end of applicability criterion 340 corresponding to the reaching of a predefined altitude such as the Cross-Over altitude XOVER. Indeed, it is entirely possible to envisage a flight phase, for example, of the CLIMB type where the Cross-Over altitude XOVER imposing the transition to a Mach instruction to allow the aircraft to be controlled coincides with the maximum altitude reached by the aircraft during a CLIMB phase. In addition, the determination step 30 makes it possible, as an additional variant, to determine a third criterion 360, representing a point of the flight plan.As an indicative example, the last point of the flight plan reflecting the end of a departure procedure in the CLIMB phase can be considered as a third end of applicability criterion allowing the CAS speed instruction and the Mach strategy to be terminated.

[0065] The third end of applicability criterion has the advantage of being able to maintain the CAS speed setpoint and / or the Mach setpoint beyond the flight phase. Thus, as an indicative example, the third end of applicability criterion makes it possible to maintain the highest speed constraint beyond the CLIMB flight phase and to also apply it in the following CRUISE phase. This scenario may occur when the aircraft's cruising level is low, for example in the case of a relatively short flight to a nearby airport, or when flight envelope restrictions limit the cruising altitude.

[0066] The method 1 for managing speed constraints may also comprise a step of deleting a speed constraint 70. Indeed, an AT OR ABOVE speed constraint is applicable from the point to which it is associated and, similarly, an AT constraint becomes a minimum speed from the point to which it is associated. Consequently, once the constraint is implemented, it is no longer possible to delete it easily since the associated point has just been sequenced and therefore has disappeared from the displayed flight plan. The deletion step 70 makes it possible to delete this speed constraint despite the absence of the point with which it is associated. Furthermore, this step of deleting a speed constraint 70 is independent of the other steps of the management method 1 and automatically results in a reset of the management method 1 and of the step of selecting a speed profile 10. Thus, the step of deleting a speed constraint 70 can be initialized following the step of determining the end of applicability criterion or precede the identification step 05 of the current flight phase, leaving an operator free to decide on the impact of any speed constraint on the flight plan of the aircraft.

[0067] Similarly, the method for managing speed constraints may comprise an additional step of adjusting the speed 80 of the aircraft relative to a speed constraint of the following flight phase. This is particularly the case when the aircraft moves from a CRUISE phase to a DESCENT phase with the appearance of a first speed constraint in the DESCENT phase that is higher, or even significantly higher, than the speed of the aircraft in the CRUISE phase.Therefore, in order not to impose too great a change in speed between the end of applicability zone of the flight phase, namely the CRUISE phase and the first speed constraint of the following flight phase, namely the DESCENT phase, the management method 1 can allow the aircraft, via the speed adjustment step 80, to adjust its speed with respect to this first speed constraint of the following phase, or DESCENT, by forcing the maintenance of the next highest speed constraint even once the end of applicability condition has been reached for the current flight phase, i.e. the CRUISE phase. This situation can arise, for example, in the case of a low cruise.Therefore, when the aircraft begins the next flight phase, namely the DESCENT phase, the aircraft maintains a high speed in accordance with the highest speed constraint of the previous flight phase, the CRUISE phase, in order to limit the speed gradient between the two flight phases and to ensure a relevant transition from the CRUISE phase to the DESCENT phase.

[0068] Furthermore, the speed constraint management method 1 comprises a speed maintenance step 60 during the current flight phase. More precisely, the maintenance step 60 imposes a maintenance speed or imposed speed on the aircraft until an event leading to the cancellation of this maintenance of the aircraft's speed. As a non-limiting example, the maintenance step 60 may impose a maintenance speed on the aircraft until a speed constraint or until an indicative speed. Indeed, when the flight phase is a CRUISE phase and the aircraft is close to a transition to the DESCENT phase, synonymous with the aircraft descending towards the airport, the maintenance step 60 makes it possible to maintain the speed of the aircraft until a constraint of speed of the DESCENT phase. Thus, the holding step 60 makes it possible to manage this CRUISE-DESCENT transition by eliminating any deceleration and / or acceleration deemed unnecessary by the flight operator, complicating the flight phase and particularly the CRUISE-DESCENT transition and considerably increasing the fuel consumption of the aircraft during the flight phase. In addition, the holding step 60 can also maintain a speed imposed on the aircraft directly in the DESCENT phase, for example, until an event cancels this maintenance. As an indicative example, the holding step 60 makes it possible to efficiently manage the transition from a current flight phase to the following flight phase, such as the CRUISE-DESCENT transition but also the CLIMB-CRUISE transition.

[0069] The management method 1 also comprises a step 65 of monitoring the speed constraints when the aircraft is traveling through a DESCENT phase or an APPROACH phase. More precisely, the monitoring step 65 allows the storage of the AT OR ABOVE speed constraints and the speed indicators generated by the BACKWARD method in order to allow compliance with the speed constraints and the speed indicators by the FORWARD method of the flight management system of the aircraft. It thus becomes possible to control and align the FORWARD method of the flight management system planning the flight plan with respect to the reference of the BACKWARD method and therefore to maintain the time predictions and the consumption of the aircraft in a more stable manner, for example.

[0070] In addition, the management method 1 may comprise a step 90 of displaying speed constraints during the flight phase. More precisely, this display step 90 makes it possible to store and display the speed constraints of the aircraft, such as, for example, the highest AT or AT OR ABOVE speed constraint potentially higher than the economic speed. This display is particularly relevant in the case cited above of the presence of a first AT or AT OR ABOVE speed constraint in a DESCENT phase while the aircraft is in the CRUISE phase. Thus, the display of this first constraint warns the operator in advance.

[0071] The invention further provides a computer program product comprising code instructions making it possible to carry out the steps of the management method 1 when said program is executed on a computer.

[0072] Embodiments of the invention may be implemented by various means, for example by hardware, software, or a combination thereof.

[0073] In general, the routines executed to implement the embodiments of the invention, whether implemented within the framework of an operating system or a specific application, a component, a program, an object, a module or a sequence of instructions, or even a subset thereof, may be referred to herein as “computer program code” or simply “program code.” Program code typically comprises computer-readable instructions that reside at various times in various memory and storage devices in a computer and that, when read and executed by one or more processors in a computer, cause the computer to perform the operations necessary to execute the operations and / or elements of various aspects of the embodiments of the invention. Computer-readable program instructions for performing the operations of the embodiments of the invention may be, for example, assembly language, or source code or object code written in combination with one or more programming languages.

Claims

Claims

1. Method for managing (1) a speed constraint of a flight plan of an aircraft, the method being implemented by computer and comprising the following steps: - Construction of a CAS speed profile (10), the speed profile establishing a behavior of the aircraft with respect to a speed setpoint, - Construction of a Mach strategy (20), the Mach strategy establishing a behavior of the aircraft with respect to a Mach setpoint, the Mach setpoint being a speed setpoint transcribed into an equivalent Mach number, - Determination of a Cross-Over altitude (50), the Cross-Over altitude being an altitude for switching from a control of the aircraft according to the CAS speed profile to a control according to the Mach strategy, - Determination of an end of applicability criterion (30) of the speed profile and the Mach strategy, - Identification (05) of a current flight phase among Climb, Cruise,Descent and Approach, - Identification of an aircraft altitude, - Selection of the CAS speed profile or Mach strategy based on a comparison between the aircraft altitude and the identified Cross-Over altitude, the CAS speed profile being selected if the aircraft altitude is less than or equal to the identified Cross-Over altitude, the Mach strategy being selected if the aircraft altitude is greater than the identified Cross-Over altitude.,

2. A method for managing speed constraints according to claim 1, wherein the speed setpoint according to the CAS speed profile is constructed on the basis of aircraft performance.

3. Method for managing speed constraints according to claim 1, in which the speed instruction according to the CAS speed profile allows the aircraft to comply with all of the AT and AT or ABOVE speed constraints during the flight phase.

4. Method for managing speed constraints according to claim 1, in which the speed setpoint according to the CAS speed profile is constructed with knowledge of a predefined target aircraft speed and a predefined speed constraint, the predefined speed constraint being an AT or AT or ABOVE speed constraint.

5. Method for managing speed constraints according to one of claims 1 to 4, in which the Mach setpoint according to the Mach strategy is determined as a function of a predefined Mach.

6. Method for managing speed constraints according to one of claims 1 to 4, in which the Mach instruction according to the Mach strategy allows the aircraft to respect all of the AT and AT or ABOVE speed constraints during the flight phase.

7. Method for managing speed constraints according to one of claims 1 to 6, in which the Cross-Over altitude is calculated as a function of a first predefined CAS AT or AT or ABOVE speed constraint, a previously defined CAS speed and a previously defined Mach.

8. Method for managing speed constraints according to one of claims 1 to 6, in which the Cross-Over altitude is a function of a second predefined CAS AT or AT or ABOVE speed constraint, an imposed flight level and a previously defined Mach.

9. Method for managing speed constraints according to one of claims 1 to 6, in which the Cross-Over altitude is the altitude allowing the aircraft to comply with the CAS speed instruction.

10. Method for managing speed constraints according to one of claims 1 to 9, in which the end of applicability criterion is an end of the flight phase or the reaching of a predefined altitude.

11. Method for managing speed constraints according to one of claims 1 to 10, comprising a step of deleting (70) a speed constraint following the step of determining the end of applicability criterion.

12. Method for managing speed constraints according to one of the preceding claims, comprising a step of maintaining (60) an imposed speed of the flight phase.

13. Method for managing speed constraints according to one of the preceding claims, comprising a step of monitoring (65) the speed constraints.

14. Method for managing speed constraints according to one of the preceding claims, comprising an additional step of adjusting the speed (80) of the aircraft with respect to a first speed constraint of the following flight phase.

15. Method for managing speed constraints according to one of the preceding claims, comprising a step of displaying (90) speed constraints during the flight phase.

16. A computer program product, said computer program comprising code instructions for carrying out the steps of the method according to any one of claims 1 to 15, when said program is executed on a computer.

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