method and multi-engine rotary-wing aircraft to simulate engine failure

Abstract

The present invention relates to a method for simulating an engine failure on a rotorcraft (1) comprising several engines (10) for setting a rotary wing (6) in motion. The method includes a training mode comprising control with a governor (30) for each engine (10) to simulate an engine failure, this control including a limitation of the power of each engine (10) to a respective control limit. The training mode comprises the following steps: i) determining, with the governor (30), on the one hand, a maximum mass based on at least external conditions and, on the other hand, an initial mass of the rotorcraft (1) based on at least the empty mass of the rotorcraft (1), the mass of a crew present in the rotorcraft (1), and an estimated mass of fuel on board; ii) comparing, with the governor (30), the initial mass to the maximum mass; iii) determining, with the governor (30), each control limit based on said comparison.Abbreviated figure: figure 1.

Description

Title of the invention: Method and multi-engine gyroplane for simulating engine failure

[0001] The present invention relates to a method and a multi-engine rotorcraft for simulating the failure of an engine.

[0002] A multi-engine rotorcraft comprises a rotating wing set in motion by a propulsion system having at least two engines.

[0003] Thus, each engine can operate according to a plurality of usual operating regimes under normal conditions, that is to say, excluding cases of failure or simulation. These usual operating regimes under normal conditions may include a continuous regime during which the engine can deliver a maximum continuous power PMC, and a takeoff regime during which the engine can deliver a maximum takeoff power PMD greater than the maximum continuous power PMC.

[0004] The engines are further sized so that the propulsion system develops sufficient engine power to ensure flight in the event of a total engine failure. Thus, each engine can operate according to a plurality of emergency modes in the event of another engine failure. These emergency modes are sometimes referred to as OEI, an acronym for "one engine inoperative." These emergency modes may include:

[0005] - a first emergency regime limited to a super emergency power called OEI30”, usable for a period of approximately thirty consecutive seconds, this first emergency mode can be used approximately three times during a flight,

[0006] - a second emergency mode limited to a maximum emergency power designated OEI2', usable for a period of approximately two minutes, and

[0007] - a third emergency regime limited to an intermediate emergency power called OEIcontinu, usable for a period covering for example the end of the flight.

[0008] The maximum power levels associated with each regime are defined in particular according to external conditions.

[0009] In order to train aircraft pilots in the total failure of an engine and the associated degraded operation, a rotorcraft may have a so-called "training" mode.

[0010] During training mode, the drive system develops an overall "reduced overall power" with the motors, capped at the power of an emergency mode. The motors may develop equivalent or different power levels for this purpose.

[0011] According to another aspect, the performance of a rotorcraft depends in fact on the mass of this rotorcraft. However, the power developed by an engine varies depending on the aircraft's altitude, particularly in the presence of turboshaft engines. A manufacturer can therefore establish the maximum permissible weight of the rotorcraft based on the intended flight altitude.

[0012] Therefore, if training mode is activated with a rotorcraft having a mass significantly lower than its maximum mass, the power required by the rotorcraft may be less than the maximum power of the tested emergency mode. This training is therefore not optimal.

[0013] However, such a training flight is often carried out with a relatively light helicopter carrying only the student pilot and their instructor. To optimize training, the instructor and student can add ballast to the helicopter. This solution does indeed bring the helicopter's mass closer to its maximum authorized mass, but it is nonetheless restrictive.

[0014] Rotorplanes can be equipped with various systems to perform a training flight in the event of an engine failure on a rotorplane.

[0015] In this context, US patent 5873546 A discloses modules and methods for weighting the power of a multi-engine helicopter propulsion system. A training mass is evaluated, in particular, based on ambient climatic conditions such as temperature and altitude.

[0016] Document EP 2254793 describes a rotorcraft equipped with an interface having two switches, to respectively simulate an aircraft with a maximum on-board load, and an aircraft with a maximum on-board load and carrying a maximum load with a hook.

[0017] Document EP2624239 describes a rotorcraft equipped with an adjustment means that can be used by an instructor to adapt the overall reduced power and simulate different failure configurations.

[0018] The present invention then aims to propose an innovative method for simulating the failure of an engine on a multi-engine rotorcraft.

[0019] The invention thus relates to a method for simulating an engine failure on a rotorcraft, the rotorcraft comprising a propulsion system equipped with several engines jointly developing an overall power to move a rotating wing, at least one engine operating by burning fuel, each engine having a control parameter capped by a regulator at a limit control value during at least one emergency regime applicable in the event of failure of another engine, the method comprising a training mode including control with the regulator of each engine in order to simulate an engine failure, said control with the regulator of each engine including a capping of the control parameter of each engine at a respective control stop.

[0020] The school mode comprises the following steps:

[0021] - determination, possibly in flight, of a school mode initialization, with the re regulator of an initial mass of said rotorcraft at least as a function of an empty mass of the rotorcraft, a parameterized mass of a crew present in the rotorcraft, an estimated mass of fuel on board,

[0022] - determination in flight, or even at initialization of the training mode, of a mass maximum for the rotorcraft established according to at least external conditions,

[0023] - comparison in flight with the regulator from initial mass to maximum mass,

[0024] - determination with the regulator of each regulation stop as a function of said comparison and of said limit regulation value.

[0025] The control parameter can be, for example, motor torque or power.

[0026] The maximum mass is determined by the controller based on external conditions, for example, using a stored mass model. For example, the controller includes a spreadsheet or a mathematical formula that provides the maximum mass based on external conditions.

[0027] This method is thus related to the application of a school mode, for example following an activation of this school mode with a human-machine control interface.

[0028] Thus, the regulator is configured to determine an initial mass of the rotorcraft, namely one substantially close to the actual mass of the rotorcraft at the initialization of training mode. This regulator compares the initial mass to the maximum mass and then regulates the engines so that the power-to-weight ratio of the rotorcraft during the application of training mode is substantially equivalent to the power-to-weight ratio that the rotorcraft would have at its maximum mass with one engine failure during the application of the current emergency mode. In other words, the lighter the rotorcraft, the lower the regulation limits of the emergency mode(s).

[0029] To this end, the controller adjusts the value of each control limit. For example, the controller applies a mathematical model, established by tests and / or simulations if necessary, to establish the control limits based on the comparison of the initial mass to the maximum mass.

[0030] By way of example, on a twin-engine rotorcraft, one engine may be sized to develop a torque of 600 Newton-meters in the current emergency operating mode under the prevailing external conditions, the other engine producing no power due to its failure. To simulate this situation on a typical rotorcraft, the two engines are controlled to, for example, each develop an engine torque of 300 Newton-meters. According to the invention, if the rotorcraft has an initial mass of approximately 80 percent of its maximum mass, then the governor can regulate each engine to limit the engine torque to 240 Newton-meters, or 80 percent of the aforementioned 300 Newton-meters.

[0031] Therefore, the method of the invention makes it possible to adapt the engine control stops during training mode according to the initial mass of the rotorcraft to simulate an engine failure occurring on a rotorcraft at its maximum mass under current external conditions. Thus, training is optimized by placing the rotorcraft in conditions close to the most unfavorable conditions, namely an engine failure in a rotorcraft at its maximum mass.

[0032] The method according to the invention may further include one or more of the following features.

[0033] Thus, the external conditions may include an external pressure and an external temperature of the air present around the rotorcraft, said initialization of the training mode including an estimation of the external pressure with an external pressure sensor of the regulator and of the external temperature with an external temperature sensor of the regulator.

[0034] This feature makes it possible to take into account the impact of external conditions on the operation of the engines.

[0035] Independently of this feature and according to a first alternative of the invention, the method may include a measurement of a current quantity of fuel in the rotorcraft with a gauge of the regulator, then an estimation of said mass of fuel as a function of the current quantity at an initialization of the training mode.

[0036] According to this first alternative, if the current quantity is a current mass of fuel then the mass of fuel is equal to the current quantity.

[0037] However, if the current quantity is a current volume of fuel, then the mass of the fuel can correspond to the product of the current volume of fuel present in the rotorcraft at the initialization of training mode and the density of the fuel. This density can be stored in the regulator. Optionally, the regulator may include a fuel list and an interface allowing a crew to select the fuel on board.

[0038] This first alternative makes it possible to estimate precisely the initial mass at an initialization of the school mode, namely following the activation of this school mode.

[0039] According to a second alternative, said training mode may include setting a pre-flight quantity of fuel with a fuel setting human-machine interface of the regulator, the method comprising: i) an estimation of a quantity of fuel consumed up to an initialization of the training mode, and ii) an estimation of said mass of fuel as a function of the pre-flight quantity of fuel as well as the quantity of fuel consumed, or even a density of the fuel.

[0040] According to the second alternative, a crew manually sets the quantity before The onboard fuel quantity is determined by the mass or volume of fuel carried. The regulator is then configured to calculate the amount of fuel consumed using at least one flow meter, for example, by multiplying the flow rate by the time period to deduce the volume. The regulator is also configured to deduce the mass of fuel at the time of training mode initialization, taking into account the fuel density if one of these quantities is a volume of fuel. For example, if the pre-flight quantity and the amount of fuel consumed are volumes of fuel, the mass of fuel is then equal to the product of the density and the arithmetic difference between the pre-flight quantity and the amount of fuel consumed.

[0041] This second alternative allows for a precise estimation of the initial mass.

[0042] According to the second alternative, the process can therefore include setting the pre-flight quantity before starting the engines with a human-machine interface for setting the fuel level of the regulator, the pre-flight quantity being fixed after said start.

[0043] According to a third alternative, the fuel mass can be parameterized with a fuel parameterization human-machine interface of the regulator.

[0044] A crew can manually set the fuel mass, for example at a school mode initialization, to test a particular configuration possibly to adapt the test to the level of a student.

[0045] Optionally, the method may include setting the fuel mass before starting the engines, the fuel mass being fixed after said start.

[0046] A single rotorcraft can optionally be configured to implement several alternatives. For example, the rotorcraft may include a human-machine interface for selecting the desired alternative, for example, based on the educational purpose of flight training in OEI mode.

[0047] Whatever the alternative, the method may include a selection of a type of drive with a human-machine interface for selecting the regulator, the determination in flight with the regulator of the maximum mass being a function of the type of drive selected with the human-machine interface for selection.

[0048] The power to be supplied by the motors varies depending on the type of drive. The process can therefore take this into account.

[0049] Optionally, said type of training may be chosen from a list including: category A training requiring the possibility of continuing the flight and category B training requiring the possibility of landing safely.

[0050] According to a possibility consistent with the preceding ones, said comparison with the regulator from the initial mass to the maximum mass may include an establishment of a ratio of proportion between the initial mass and the maximum mass.

[0051] The ratio can be set to 1 by default for safety reasons.

[0052] According to a first variant, the determination with the regulator of each control stop as a function of the comparison may include for each motor: i) an estimation of a calculation control value as a function of the ratio ratio and the limit control value, then ii) a determination of the control stop as a function of the calculation control value and a distribution coefficient specific to each control stop.

[0053] The calculated control value can be equal to the product of the proportion ratio and the limit control value. A control stop can be equal to the product of the calculated control value and the associated distribution coefficient.

[0054] In this case, the controller estimates the limit control values ​​in the usual way, and then deduces the control limits. For example, the distribution coefficient may be equal to the number of motors in operation.

[0055] Alternatively, said determination with the regulator of each control stop as a function of said comparison may include for each motor i) an estimation of an intermediate value as a function of a distribution coefficient specific to each control stop and the limit control value, then ii) a determination of each control stop as a function of said intermediate value and said proportion ratio.

[0056] The intermediate value can be equal to the product of the associated distribution coefficient and the limit control value. A control stop can be equal to the product of the intermediate value and the proportion ratio.

[0057] This alternative can be easily implemented in an aircraft equipped with engine control units that cap a control parameter at an intermediate value for each engine during training mode. Indeed, the engine control units can be modified to receive the proportion ratio and apply it to the intermediate value determined in the usual way.

[0058] According to a possibility compatible with the preceding ones, the method may include a parameterization before engine start of the empty mass with an empty mass human-machine interface of the regulator, and a parameterization before engine start of the mass of a crew present in the rotorcraft with a crew mass human-machine interface of the regulator, the empty mass and the mass of a crew present in the rotorcraft being fixed after said start.

[0059] According to one example, the empty mass can be equal to a sum of a bare mass of the rotorcraft, parameterized with the empty mass human-machine interface or stored, a mass of optional equipment parameterized with the empty mass human-machine interface, and a freight mass parameterized with the human-machine interface of empty mass.

[0060] According to another example, the empty mass can be equal to a sum of a bare mass of the empty aircraft, parameterized with the empty mass human-machine interface or stored or even including installed optional equipment, and a freight mass parameterized with the empty mass human-machine interface.

[0061] According to one example, the empty mass can be equal to the mass parameterized with the empty mass human-machine interface.

[0062] According to a possibility compatible with the preceding ones, the method may include a measurement of a rotation speed of the rotating wing with a rotation speed sensor of the regulator, an automatic disengagement with the regulator from training mode as soon as the rotation speed is below a memorized threshold, and a generation of an alert carrying the disengagement.

[0063] The training mode can be automatically deactivated if the overall power developed is insufficient to drive the rotary wing at a minimum rotation speed. The crew is informed of this.

[0064] The invention also relates to a rotorcraft comprising a propulsion system equipped with several motors jointly developing an overall power to move a rotating wing, each motor developing a power capped by a regulator at a limit power value when at least one emergency mode is applied in the event of failure of at least one other motor.

[0065] The regulator is thus configured to apply the process of the invention.

[0066] For this purpose, the regulator may include, for example, a fuel metering device per engine controlled by a controller. The controller may be in communication with at least one of the following: an external pressure sensor, an external temperature sensor, a rotational speed sensor measuring the rotational speed of the rotor, at least one engine regulation sensor, an empty mass human-machine interface, a crew mass human-machine interface, a selection human-machine interface, a choice human-machine interface, a fuel parameterization human-machine interface.

[0067] The invention and its advantages will become apparent in more detail in the following description, with illustrative examples given by reference to the accompanying figures, which represent:

[0068] [Fig. 1], a view of a rotorcraft according to the invention,

[0069] [Fig.2], a flowchart showing the process according to the invention,

[0070] [Fig. 3], a logic diagram showing a method for estimating the mass of fuel,

[0071] [Fig. 4], a flowchart showing a method for estimating the mass of fuel, and

[0072] the [Fig.5], a flowchart showing a method for estimating the mass of fuel.

[0073] Elements present in several separate figures are assigned one and the same reference.

[0074] Figure 1 shows an example of a rotorcraft 1 according to the invention. This rotorcraft 1 comprises a rotating wing 6.

[0075] The rotorcraft 1 further comprises a drive system 2 for rotating the rotating wing 6, for example to provide lift, or even forward motion, of this rotorcraft 1. This drive system 2 is equipped with at least two motors 10. Reference 10 designates any motor, references 11, 12 designating particular motors if necessary to identify a specific motor 10.

[0076] At least one or even each engine 10 is supplied with fuel 21 from at least one tank 20 via a fuel circuit.

[0077] By way of example, at least one engine 10 may be a turboshaft engine. Such a turboshaft engine 10 comprises a gas generator which is equipped with at least one compression turbine 13, a combustion chamber 14 into which the fuel 21 is injected and at least one expansion turbine 15 rotationally linked to the compression turbine(s) 13. In addition, the turboshaft engine 10 may comprise at least one free turbine 16 which directly or indirectly drives a power shaft 17 of the engine.

[0078] Regardless of the type of motors, each motor 10 may include a power shaft 17 connected to a power transmission chain 5. The power transmission chain 5 is then connected in the usual way to the rotating wing 6. By way of illustration, the power transmission chain 5 may be equipped with a power transmission box which is mechanically interposed between the motors 10 and the rotating wing 6. The power transmission chain 5 may include at least one freewheel, and / or at least one connecting shaft, and / or at least one connector allowing misalignments...

[0079] Furthermore, the engines 10 are internal combustion engines operating on fuel 21. The engines 10 can operate in a plurality of modes, including one of the aforementioned modes, namely continuous mode, takeoff mode, first emergency mode, second emergency mode, and third emergency mode. Therefore, the rotorcraft 1 includes a control system, more simply called a "controller 30," to regulate the power or torque delivered by each engine 10 with its power shaft 17, depending in particular on the current operating mode applied.

[0080] Thus, the regulator 30 can include a fuel metering device 18 per engine 10, for example on the fuel circuit linking the tank(s) 20 to the associated engine 10. Each engine 10 is then connected via its own fuel metering unit 18 to at least one fuel tank 20. Reference number 18 designates any fuel metering unit, while reference numbers 181 and 182 designate specific fuel metering units for the two engines 11 and 12, respectively.

[0081] Furthermore, the regulator 30 may include at least one flow meter 50 arranged on the fuel circuit to evaluate the quantity of fuel consumed since the start of the engines 10.

[0082] Furthermore, the regulator 30 may include a gauge 35 for evaluating the quantity of fuel stored in the tank(s) 20. Such a gauge 35 may include, for example, one or more conventional gauging rods, this example being given simply to illustrate the regulator 30.

[0083] Furthermore, the regulator 30 may include one engine control unit 80 per engine 10. Each engine control unit 80 may include, for example, at least one processor and at least one memory, at least one integrated circuit, at least one programmable system, at least one logic circuit, these examples not limiting the scope given to the expression "engine control unit". The engine control units may communicate with each other by wired or wireless links.

[0084] According to the example described, the drive system 2 comprises two engine control units 81, 82, each controlling one of the two motors 11, 12. Each engine control unit 81, 82 is configured to drive its associated motor 11, 12 and operate it at the required speed, for example, so that the controlled motor 11, 12 has a control parameter capped at a limit value for that speed. The control parameter could be, for example, the motor torque or the power developed by the motor.

[0085] The limiting regulation value is established for a rotorcraft 1 in a usual way. For example, each engine computer determines, according to the applicable speed, a first torque limit to be respected in order not to damage the power transmission chain 5 as well as a temperature limit of the engine concerned converted into a second torque limit and a rotational speed limit of the engine gas generator converted into a third torque limit and determined according to the external conditions, the limiting regulation value being equal to the smallest of these torque limits.

[0086] Each engine control unit 81, 82 can, in particular, control the fuel metering unit 181, 182 of the associated engine 11, 12. Each engine control unit 81, 82 can be connected to multiple control sensors to control the associated engine 11, 12, such as, for example, a torque meter 901, 902 measuring engine torque on a rotating component. Such a rotating component can be a power shaft 17 of an engine 10. For example, the fuel metering unit 181, 182 is controlled via the implementation of a loop regulation aimed at maintaining the torque developed by the rotating part less than or equal to the current limit regulation value.

[0087] The regulator 30 may further include a controller 60 communicating with the engine control units 80. The controller 60 may include, for example, at least one processor and at least one memory, at least one integrated circuit, at least one programmable system, at least one logic circuit; these examples do not limit the scope given to the expression "engine control unit". The controller 60 may communicate via wired or wireless links with each engine control unit 80, or may even be integrated with at least one engine control unit 80.

[0088] The controller 60 can communicate via wired or wireless links with, where applicable, the gauge 35 and the flowmeter 50.

[0089] Regardless of its composition, the controller 60 can communicate via a wired or wireless link with at least one alert device 65 to provide information to a pilot. Such an alert device 65 may, for example, include a display capable of showing a message, a light-emitting diode that illuminates upon command from the controller 60, a loudspeaker...

[0090] In addition, the controller 60 can communicate with one or more human-machine interfaces. Each human-machine interface can include at least one device operable by a pilot, such as a button or lever, a touchscreen, a voice command...

[0091] Therefore, the controller 60 can communicate with a fuel parameterization human-machine interface 51. This fuel parameterization human-machine interface 51 transmits a signal to the controller 60 carrying a pre-flight quantity of fuel, namely a pre-flight mass or volume of fuel.

[0092] The term signal refers to a digital or analog, optical or electrical signal.

[0093] The controller 60 can communicate with a selection human-machine interface 52. This selection human-machine interface 52 transmits a signal to the controller 60 carrying a selected drive type. For example, the drive type is chosen from a list including a category A drive requiring the ability to continue flight after an engine failure and a category B drive requiring the ability to land safely after an engine failure.

[0094] The controller 60 can communicate with an empty mass human-machine interface 53. The term empty mass refers to the mass of the rotorcraft 1 without fuel and without crew. This empty mass human-machine interface 53 transmits a signal, called the "empty mass signal" for convenience, to the controller 60, which carries an empty mass of the rotorcraft 1. This empty mass can vary depending on the optional equipment fitted to the rotorcraft 1, or even the onboard ballast. The empty mass human-machine interface 53 can be used to configure all configurable stations influencing the empty mass, such as the bare mass of the rotorcraft, the mass of the cargo, the mass of the equipment.

[0095] The controller 60 can communicate with a crew mass human-machine interface 54. This crew mass human-machine interface 54 transmits a signal, referred to for convenience as the "crew mass signal", to the controller 60 carrying a crew mass, namely the mass of all the occupants of the rotorcraft 1.

[0096] The controller 60 can communicate with a human-machine interface 55 for activating school mode. This human-machine interface 55 for activating school mode transmits a signal to the controller 60 carrying a school mode activation.

[0097] The controller 60 can communicate with a density human-machine interface 56. This density human-machine interface 56 transmits a signal, referred to for convenience as the "density signal," to the controller 60, which carries the density of the onboard fuel. This signal can either include the density itself or the type of fuel, the controller storing the associated density for each type of fuel.

[0098] Furthermore, the controller 60 can be connected to one or more sensors, for example by wired or non-wired connections.

[0099] The controller 60 can be connected to an external pressure sensor 41 transmitting a signal, called a "pressure signal" for convenience, carrying an external pressure PO of the air surrounding the rotorcraft 1.

[0100] In addition, the controller 60 can be connected to an outside temperature sensor 42 transmitting a signal, called a "temperature signal" for convenience, carrying an outside temperature T0 of the air surrounding the rotorcraft 1.

[0101] Furthermore, the controller 60 can be connected to a rotation speed sensor 66 transmitting a signal, referred to for convenience as the "rotation speed signal," carrying a rotation speed NR of the rotating wing. Such a sensor is known from the prior art.

[0102] In this context, during normal operating mode, each fuel metering unit 18 is controlled by the corresponding engine control unit 80 so that the drive system 2 develops an overall power WGLOB.

[0103] In the event of failure of one of the engines 10, each fuel metering unit 18 of an engine remaining in operation is controlled by the corresponding engine computer 80 so that the engine 10 develops with its power shaft 17 an emergency driving power, a regulation parameter of the operating engine being capped at a limit regulation value corresponding to the current emergency mode.

[0104] Fig. 2 then illustrates examples of a method for simulating an engine failure that can be implemented by the rotorcraft of Fig. 1.

[0105] To this end, the method may include activating a school mode (STP0). By For example, an instructor or student pilot requests the human-machine interface 55 to activate training mode. This human-machine interface 55 transmits a signal to the controller 60, which activates training mode.

[0106] Regardless of how it is activated, the training mode includes a STPM determination with the regulator 30 of an initial mass MINIT of the rotorcraft 1 at least as a function of the parameterized empty mass MVD of the rotorcraft 1, the parameterized MPIL mass of the crew, and a mass of fuel MCARBU on board. Optionally, the type of training is also taken into account.

[0107] To this end, in preparation for this simulation, the method may include an STPMVD parameterization prior to engine start-up of the MVD empty mass. A crew requests input from the empty mass human-machine interface 53, which transmits an empty mass signal to the controller 60. The controller 60 decodes the empty mass signal, then deduces and stores an MVD empty mass value. This MVD empty mass is optionally fixed after engine start-up and can no longer be modified.

[0108] Similarly, the method may include a pre-setting of the crew's MPIL mass before the engines 10 start. A crew requests the crew mass human-machine interface 54, which transmits a crew mass signal to the controller 60. The controller 60 decodes the crew mass signal and then deduces and stores a crew mass MPIL value. This crew mass MPIL is optionally fixed after the engines 10 start and can no longer be modified.

[0109] In addition, the regulator 30 determines the mass of fuel MCARBU. Figures 3 to 5 illustrate three possible alternatives for determining the mass of fuel MCARBU.

[0110] According to the first alternative in [Fig. 3], the training mode includes a measurement MESCARBU of a quantity, and possibly a volume, of fuel in the rotorcraft 1 using the gauge 35. The gauge 53 transmits a signal, conveniently called the "fuel signal," to the controller 60, which carries the volume or mass of fuel contained in the tank(s) 20. The controller 60 decodes the fuel signal and deduces the fuel mass MCARBU during a fuel mass estimation step ESTCARBU1. For example, the fuel mass MCARBU is then equal to the product of the fuel volume measured by the gauge and its density. The density can be stored or parameterized using a density human-machine interface 56.

[0111] According to the second alternative in [Fig. 4], the training mode includes an STPC1 parameter setting of a pre-flight mass or volume of fuel, referred to as the "pre-flight quantity," with the fuel parameterization human-machine interface 51. This STPC1 parameter setting can be performed before starting the engines 10, the pre-flight mass, or the The pre-flight volume is fixed after said start-up.

[0112] This fuel parameterization man-machine interface 51 transmits a signal to the controller 60. The controller 60 decodes it and stores the pre-flight mass or pre-flight volume.

[0113] In addition, the training mode includes an STPC2 estimate of the volume of fuel consumed up to initialization using, for example, the flow meter 50 or the gauge 35. The controller 60 receives a signal from the flow meter 50 or the gauge 35 and can deduce from it at any given time the volume of fuel consumed since the engines 10 started.

[0114] Therefore, the regulator 30, or even the controller 60, performs an estimate ESTCARBU2 of the fuel mass based on the pre-flight mass or volume of fuel, as well as the volume of fuel consumed, or even a fuel density. For example, the controller 60 calculates the arithmetic difference between the pre-flight volume of fuel and the volume of fuel consumed and multiplies this difference by the fuel density.

[0115] According to the third alternative in [Fig. 5], the fuel mass is set during an STPC3 parameterization step using the fuel parameterization human-machine interface 51. This fuel parameterization human-machine interface 51 transmits a signal directly to the controller carrying the fuel mass MCARBU. Optionally, this STPC3 parameterization is performed before starting the engines 10, the fuel mass being fixed after said start. Alternatively, this STPC3 parameterization is performed in flight during the initialization of training mode.

[0116] Regardless of the alternative, controller 60 determines the initial mass MINIT during the initialization phase using the empty mass MVD, the mass MPIL of a crew present in the rotorcraft 1, and the mass of fuel MCARBU. Controller 60 can calculate the initial mass MINIT based on these inputs, this initial mass MINIT representing the estimated current mass of the rotorcraft 1. The initial mass MINIT can be equal to the sum of the empty mass MVD, the mass MPIL of a crew present in the rotorcraft 1, and the mass of fuel MCARBU.

[0117] Regardless of how the initial mass MINIT is determined, the training mode includes an in-flight determination STPMAX of the maximum mass depending on external conditions and also on the type of training.

[0118] Thus, a school mode initialization may include an STPEXT estimation of the outside pressure PO and the outside temperature T0. The outside pressure sensor 41 transmits a pressure signal to the controller 60, the controller 60 decoding the pressure signal and storing the outside pressure PO. Similarly, the outside temperature sensor 42 transmits a temperature signal to the controller 60, the controller 60 decoding the temperature signal and storing the outside temperature T0

[0119] Optionally, the method includes a SELECTTYP selection of a drive type using the human-machine selection interface 52 at any time before the maximum mass calculation. A crew requests input from the human-machine selection interface 52, which transmits a drive type signal to the controller 60. The controller 60 decodes the drive type signal and stores the drive type.

[0120] Therefore, the regulator 30, or even the controller 60, applies a mathematical model providing the maximum mass MMAX as a function of external conditions or even the type of drive. Such a model may include one or more mathematical laws, artificial intelligence, or other means. The model may be established through tests and / or simulations, for example.

[0121] Regardless of how the maximum mass MMAX and the initial mass MINIT are determined, the training mode includes a comparison STPCOMP with the controller 30, for example with the controller 60, of the initial mass MINIT with the maximum mass MMAX. This comparison STPCOMP may include establishing a ratio ratio RAP between the initial mass MINIT and the maximum mass MMAX. The ratio ratio RAP may be equal to the initial mass MINIT divided by the maximum mass MMAX.

[0122] Therefore, the training mode includes a STPAJUST determination with the controller 30 of each OEITRAIN regulation stop based on this comparison, and where applicable, the RAP proportion ratio. This step can be carried out with the controller 60 and / or with each engine control unit 80.

[0123] According to the first variant illustrated in solid lines, the regulator 30, or even the controller 60 or the engine control units 80, are configured to perform an STPA1 estimation of a WLIM calculation control value as a function of said RAP ratio and the VLIM limit control value. The WLIM calculation control value can be equal to the product of the RAP ratio and the VLIM limit control value. The regulator 30 is configured to perform an STPA2 determination of each OEITRAIN control stop as a function of the associated WLIM calculation control value and a distribution coefficient COEF specific to each OEITRAIN control stop. This distribution coefficient can be stored. The sum of the distribution coefficients is equal to one.

[0124] According to a numerical example applied to a twin-engine rotorcraft, the proportion ratio is 0.8, the initial mass being equal to 80 percent of the maximum mass. According to this example, the limiting control value to which an engine is stopped during the applied emergency mode is 600 Newton-meters. Furthermore, the overall power during the school mode is equally distributed which induces a repair coefficient equal to 0.5 in the presence of two motors 10. Therefore, the controller 60 or the motor computers 80 deduce that the WLIM calculation regulation value is equal to 0.8 times 600 or 480 Newton-meters, each motor 10 being finally limited to a motor torque of 480 times 0.5 or 240 Newton-meters.

[0125] According to the second variant illustrated in dotted lines, the regulator 30, or even the controller 60 or the engine control units 80, are configured to perform an STPA3 estimation for each OEITRAIN control stop of an intermediate value VINT based on a distribution coefficient COEF specific to each OEITRAIN control stop and the limit control value of these engines. The regulator 30 is configured to perform an STPA4 determination of each control stop based on said intermediate value VINT and said proportion ratio RAP.

[0126] According to a numerical example applied to a twin-engine rotorcraft, the proportion ratio is 0.8, the initial mass being equal to 80 percent of the maximum mass. According to this example, the limiting regulation value to which an engine is stopped during the applied emergency mode is 600 Newton-meters. Furthermore, the overall power during training mode is equally distributed, which induces a repair factor of 0.5 with two engines present. Therefore, engine computers, for example, deduce that the intermediate value VINT is equal to 0.5 times 600, or 300 Newton-meters, each engine 10 ultimately being limited to an engine torque of 300 times 0.8, or 240 Newton-meters.

[0127] Regardless of the variant, the school mode then includes STPREG regulation with the regulator 30 of each motor 10 in the usual way, the regulation parameter of each motor 10 being controlled so as not to exceed the respective OEITRAIN regulation stop.

[0128] Optionally, the training mode may include an STPNR measurement of the rotation speed NR of the rotary wing 6 with the rotation speed sensor 66. The controller 60 receives the rotation speed signal emitted by the sensor 60, decodes it, and deduces the current rotation speed NR of the rotary wing 6.

[0129] If the rotation speed NR is greater than a stored threshold NRS, training mode continues. Optionally, training mode can be deactivated by a crew, for example using the training mode activation human-machine interface 55.

[0130] However, if the rotational speed NR falls below the threshold NRS, the controller 30 is configured to perform an automatic STPEXIT disengagement with the controller 30 in training mode. Furthermore, the controller 60 transmits a warning signal to the alerter 65, the alerter 65 being configured to generate an STPWARN alert indicating disengagement.

[0131] Naturally, the present invention is subject to many variations as to its Implementation. Although several embodiments have been described, it is understood that it is not possible to exhaustively identify all possible embodiments. It is, of course, conceivable to replace a described means with an equivalent means without departing from the scope of the present invention and the claims.

Claims

Demands

1. Method for simulating an engine failure on a rotorcraft (1), the rotorcraft (1) comprising a propulsion system (2) equipped with several engines (10) jointly developing a total power (WGLOB) to move a rotary wing (6), at least one engine (10) operating by burning fuel, each engine (10) having a control parameter capped by a controller (30) at a limit control value during at least one emergency regime applicable in the event of a failure of another engine (10), the method comprising a training mode including control (STPREG) with the controller (30) of each engine (10) in order to simulate an engine failure, said control (STPREG) with the controller (30) of each engine (10) including a capping of the control parameter of each engine at a respective control stop (OEITRAIN),characterized in that said training mode comprises the following steps: - determination (STPM) with the controller (30) of an initial mass (MINIT) of said rotorcraft (1) at least as a function of an empty mass (MVD) of the rotorcraft (1), a parameterized mass (MPIL) of a crew present in the rotorcraft (1), and an estimated mass of fuel (MCARBU) on board, - determination (STPMAX) in flight with the controller of a maximum mass for the rotorcraft established as a function of at least external conditions (PO, T0), - comparison (STPCOMP) in flight with the controller (30) of the initial mass (MINIT) to the maximum mass (MMAX), - determination (STPAJUST) with the controller (30) of each control stop (OEITRAIN) as a function of said comparison and said limit control value.

2. Method according to claim 1, characterized in that the external conditions comprise an external pressure (PO) and an external temperature (T0) of the air present around the rotorcraft (1), said training mode comprising an estimation (STPEXT) of the external pressure (PO) with an external pressure sensor (41) of the regulator (30) and of the external temperature (T0) with an external temperature sensor (42) of the regulator (30).

3. A method according to any one of claims 1 to 2, characterized in that the training mode includes a measurement (MESCARBU) of a current quantity of fuel in the rotorcraft (1) with a gauge (35) of the regulator (30), and an estimation (ESTCARBU1) of said mass of fuel as a function of said current quantity of fuel at an initialization of the training mode, the current quantity being a current mass or a current volume.

4. A method according to any one of claims 1 to 2, characterized in that said training mode includes a pre-flight fuel setting (STPC1) with a fuel setting human-machine interface (51) of the regulator (30), the training mode comprising: i) an estimate (STPC2) of a quantity of fuel consumed up to an initialization (INI) of the training mode, and ii) an estimate (ESTCARBU2) of said mass of fuel as a function of the pre-flight fuel quantity and the quantity of fuel consumed.

5. Method according to claim 4, characterized in that the method includes a parameterization (STPC1) before a start of the engines (10) of the pre-flight quantity with a human-machine interface (51) for parameterizing the fuel of the regulator (30), the pre-flight quantity being fixed after said start.

6. A method according to any one of claims 1 to 2, characterized in that said fuel mass is parameterized with a fuel parameterization human-machine interface (51) of the regulator (30).

7. Method according to claim 6, characterized in that the method includes a parameterization (STPC3) before a start of the engines (10) of the fuel mass, the fuel mass being fixed after said start.

8. A method according to any one of claims 1 to 7, characterized in that the method comprises a selection (SELECTTYP) of a drive type with a controller selection human-machine interface (52), the determination (STPMAX) in flight with the controller of the maximum mass being a function of the drive type selected with the selection human-machine interface (52).

9. The method according to claim 8, characterized in that said type of drive is selected from a list comprising: a category A drive requiring the ability to continue flight after engine failure and a category drive B requiring the possibility of a safe landing after engine failure.

10. A method according to any one of claims 1 to 9, characterized in that said control parameter is a motor torque or a power.

11. A method according to any one of claims 1 to 10, characterized in that said comparison (STPCOMP) with the regulator (30) of the initial mass (MINIT) to the maximum mass (MMAX) comprises an establishment (STPR) of a ratio (RAP) between the initial mass (MINIT) and the maximum mass (MMAX)

12. Method according to claim 11, characterized in that said determination (STPAJUST) with the regulator (30) of each control stop (OEITRAIN) as a function of said comparison comprises for each motor: i) an estimation (STPA1) of a calculation control value (WLIM) as a function of said proportion ratio (RAP) and the limit control value, then ii) a determination (STPA2) of the control stop (OEITRAIN) as a function of said calculation control value (WLIM) and a distribution coefficient (COEF) specific to each control stop (OEITRAIN).

13. Method according to claim 11, characterized in that said determination (STPAJUST) with the regulator (30) of each control stop (OEITRAIN) as a function of said comparison comprises for each motor: i) an estimation (STPA3) of an intermediate value (VINT) as a function of a distribution coefficient (COEF) specific to each control stop (OEITRAIN) and the limit control value, then ii) a determination (STPA4) of each control stop as a function of said intermediate value (VINT) and said proportion ratio (RAP).

14. A method according to any one of claims 1 to 13, characterized in that the method comprises a parameterization (STPMVD) before engine start of the empty mass (MVD) with an empty mass man-machine interface (53) of the regulator (30), and a parameterization (STPMPIL) before engine start of the mass (MPIL) of a crew present in the rotorcraft (1) with a crew mass man-machine interface (54) of the regulator (30), the empty mass (MVD) and the mass (MPIL) of a crew present in the rotorcraft (1) being fixed after said start.

15. A method according to any one of claims 1 to 14, characterized in that the method includes a measurement (STPNR) of a rotation speed (NR) of the rotary wing (6) with a rotation speed sensor (NR) of the regulator (30), an automatic disengagement (STPEXIT) with the regulator (30) from training mode as soon as the rotation speed (NR) is below a stored threshold (NRS), and a generation (STPWARN) of an alert carrying the disengagement.

16. Rotorplane (1) equipped comprising a propulsion system (2) equipped with several motors (10) jointly developing a total power (WGLOB) to move a rotary wing (6), each motor (10) developing a power capped by a regulator (30) at a limit power value when at least one emergency mode is applied in the event of failure of at least one other motor, characterized in that the regulator (30) is configured to apply the method according to any one of claims 1 to 15.

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