Diagnosis of an aircraft engine control unit

Abstract

An apparatus (24) and a method for diagnosing an engine control unit (16) of an aircraft are disclosed, said apparatus comprising an autonomous and mobile electronic diagnostic unit (26) and a connection member (28) for connecting the unit to the engine control unit of the aircraft, said connection member advantageously comprising a single connection cable (38).

Description

Technical Field

[0001] This invention relates to the diagnosis of aircraft engine control units, and particularly to the main control unit for regulating the engine. Background Technology

[0002] Background art specifically includes documents FRA1-3 078 791, US-A1-6,442,498, EP-A1-3 614154 and US-A1-4,567,756.

[0003] Aircraft engines (such as turbines) are equipped with control units for regulating the engine. This main control unit (also known as the Digital Engine Control Unit, DECU) must be tested during regular maintenance operations to ensure its proper functioning and trouble-free operation. The main control unit can be likened to the brain of the engine, and its proper functioning is crucial to the operation and operability of the aircraft's engine.

[0004] Diagnostics are performed during maintenance operations on the control unit. The purpose of diagnostics is to test the control unit to identify potential faults or failures.

[0005] In the existing technology, there are multiple methods to perform this maintenance operation.

[0006] In the first method, diagnostics are performed on a test bench. In practice, the control unit must be removed from the engine and then mounted on the test bench to test multiple functions of the control unit. The test bench is relatively heavy, weighing several hundred kilograms, and is fragile. Therefore, the test bench is not easy to transport and is usually stored in the workshop where diagnostics are performed. The test bench has several functions, including:

[0007] This test bench reproduces and simulates engine behavior, and analyzes the control unit's response to verify its correct operation.

[0008] This test bench tests certain behaviors of the control unit to identify potential faults.

[0009] -wait.

[0010] In the second case, the fault may originate from the control unit or a component connected to that control unit (such as a wiring harness or multiple devices). Multiple devices may include, for example, sensors or actuators.

[0011] One solution to make diagnostic devices lighter is to limit their functionality. For example, a device whose primary function is to detect certain faults in the control unit can be smaller and lighter than the test benches described above.

[0012] However, a problem with this diagnostic device remains the electrical connection between it and the control unit and the component under test. In practice, to perform tests, it's necessary to connect the device to the control unit and the component, which has many different connectors. Therefore, it's necessitated to set up multiple different connecting members and insert and remove connectors according to the tests to be performed, which is lengthy and tedious. Furthermore, the device will be equipped with numerous connection ports, so it must be excessively large to accommodate all these ports on a single surface. The connecting members connect the device to the control unit and multiple devices, and the number of connecting members will be so large that they may become tangled and interfere with maintenance operations.

[0013] In the second method, diagnostics are performed by attaching diagnostic tools to the aircraft's cockpit, with one of the aircraft's engines equipped with a control unit to be tested. The advantage of this method is that it does not require engine removal. However, this method has some disadvantages, particularly because it can identify faults but not their source. Therefore, once a fault is identified, it is necessary to investigate the root cause (of the control unit or a component connected to the control unit), as known faults may be related to operational or communication problems between the two components. Consequently, numerous tests are required to verify potential faults, some of which require removing a device and replacing it with an equivalent device. Removing a device is a complex operation because a removed and tested device must be re-inspected before being reassembled onto the aircraft. In fact, it is possible that the removed and tested device is functioning correctly. Therefore, fault identification involves the removal and reassembly of many devices, which increases the risk of diagnostic errors and makes maintenance time-consuming and expensive. No Fault Found (NFF) is a term used to describe situations where components are removed from the engine while the engine is in good condition. The NFF rate should be kept as low as possible to reduce the time and cost of maintenance operations on the aircraft control unit.

[0014] The last method is to manually measure the components of the engine that are hooked onto the aircraft, but this method cannot perform automatic diagnostics.

[0015] Therefore, there is a need to find a diagnostic solution that is simple to use and does not require the disassembly and removal of engine components, so that maintenance operations on the control unit do not result in significant aircraft downtime. Summary of the Invention

[0016] According to a first aspect, the present invention relates to a diagnostic device for an aircraft engine control unit, the device comprising:

[0017] - An electronic diagnostic unit, which is autonomous and mobile, and configured to perform:

[0018] Automated continuity testing and / or electrical insulation testing of electrical connectors, and determination of the health status of these connectors based on the test results, and / or

[0019] Automated testing is performed to verify the internal electrical integrity of the control unit without simulating flight conditions of the engine connected to the control unit.

[0020] - A connecting member configured to connect the unit to the control unit of the aircraft engine.

[0021] The characteristic feature is that the connecting member includes a single connecting cable, which includes a first connecting plug at one end for connecting to the unit, and a plurality of second connecting plugs at the opposite end for connecting to the control unit and / or the aircraft engine, and is intended to be connected to the elements of the unit.

[0022] In this application, the following definitions apply:

[0023] - An autonomous diagnostic unit configured to perform tests autonomously and identify faults based on the results of these tests, thereby determining the health status of the control unit and / or components connected to the control unit; the device is, for example, equipped with at least one power battery;

[0024] - A mobile unit that is easy for the user to transport; that is, the weight and size of the unit mean that the user can lift and move it from its storage location to the aircraft base for maintenance.

[0025] Therefore, this invention proposes a single cable for connecting the device and unit to the control unit, which simplifies and speeds up the maintenance of the control unit. There is no longer any risk of using incorrect connecting components or connecting components equipped with incorrect plugs. Furthermore, providing a single plug on one side of the cable ensures error prevention, thereby avoiding reverse installation of the cable during connection.

[0026] When performing both types of tests (continuity / insulation and integrity verification), the same cable can be plugged into the unit. Alternatively, when the unit performs continuity / insulation testing, a single first cable can be connected to the unit, and when the same unit performs integrity verification testing, a single second cable can be plugged into the same unit. Advantageously, the cable will then be mechanically fault-proofed and / or can be combined with an internal electrical fault-proofing system, which will be detected by the unit to perform either test.

[0027] The apparatus according to the invention may include one or more of the following features, which may be considered individually or in combination with each other:

[0028] - The cable includes a first section having a single branch and a second section having multiple parallel branches, wherein the branch of the first section is provided with a first plug at the end of the first section opposite to the second section, and the branch of the second section is provided with a second plug at the end of the second section opposite to the first section.

[0029] - The first segment has a length L1, and the second segment has a maximum length L2, where L1 > k.L2, and k is at least equal to 1, preferably at least equal to 2;

[0030] - At least some of the branches in the second section have different lengths;

[0031] - The device also includes a portable computer system, the unit and the computer system being configured to communicate via a wireless link;

[0032] - The second plug of the cable includes a plug configured to connect to a port of the control unit, and other plugs configured to connect to complementary plugs of multiple devices of the wiring harness or aircraft engine.

[0033] - This unit is configured to measure the impedance value, compare the measured value with the theoretical value pre-stored in the unit, and transmit a signal based on the comparison result;

[0034] - This unit includes a signal generation module, a signal acquisition module, a data generation module, a data acquisition module, at least one data storage device, a data processing module, and a data communication module, etc.

[0035] - The unit is in the form of a suitcase, which has a closed lid and at least one handle.

[0036] The present invention also relates to the use of an apparatus for diagnosing a control unit of an engine hooked to an aircraft, according to any of the foregoing embodiments.

[0037] Preferably, the engine is a propulsion assembly equipped with a cabin, and the control unit is located in the cabin.

[0038] Preferably, the control unit is FADEC3 or DECU.

[0039] According to a second aspect, the present invention relates to a method for diagnosing an aircraft engine control unit by means of a diagnostic apparatus, the diagnostic apparatus comprising:

[0040] - An electronic diagnostic unit, which is autonomous and mobile, and configured to perform automated continuity testing and / or electrical insulation testing of electrical connectors, and determine the health status of these connectors based on the test results, and

[0041] - A connecting member configured to connect the unit to the control unit of the aircraft engine.

[0042] The method is characterized by being performed simultaneously with the engine being hooked onto the aircraft, and includes the following steps:

[0043] - Disconnect at least one wiring harness that connects the control unit to multiple devices.

[0044] - The connecting member is inserted into the unit on one side and into the wiring harness and multiple devices on the other side to replace at least one disconnected wiring harness, and

[0045] -Analyze the health status of wire harnesses and multiple devices by performing automated continuity tests and / or electrical insulation tests on electrical connectors on wire harnesses and multiple devices.

[0046] Therefore, this method enables the verification of the health status of wiring harnesses and multiple devices (such as actuators and sensors) connected to the control unit. This verification is performed by testing the electrical continuity and electrical insulation of the connectors. For example, an electrical wiring harness is connected to connectors at its ends, and the electrical continuity between these connectors must be ensured. The electrical continuity test between these connectors should verify that the continuity has not been broken or interrupted. Furthermore, one strand of the wiring harness must be electrically isolated from another strand in the harness. Therefore, the connectors connected to the ends of these multiple strands of wiring harness must be electrically insulated from each other. The electrical insulation test between these connectors should verify this insulation, thereby verifying that no short circuit has occurred between these multiple strands of wiring harness.

[0047] The method according to the invention may include one or more of the following features and / or steps, which may be considered individually or in combination with each other:

[0048] - Multiple devices include actuators and / or sensors;

[0049] - Each test in the test includes: measuring the impedance value, comparing the measured value with the theoretical value pre-stored in the unit, and transmitting a signal based on the comparison result;

[0050] - Continuity testing is performed by plugging the connecting components into a single port on the unit, as well as into plugs on the wiring harness and multiple devices;

[0051] Insulation tests are performed by plugging connecting components into a single port on the unit, as well as into plugs on the wiring harness and multiple devices, including a grounding socket connected to the metal housing of the engine.

[0052] - The connecting component includes a single connecting cable, which has a first connecting plug at one end for connecting to the unit and multiple second connecting plugs at the opposite ends for connecting to the wiring harness and multiple devices.

[0053] According to a third aspect, the present invention relates to a method for diagnosing an aircraft engine control unit by means of a diagnostic apparatus, the diagnostic apparatus comprising:

[0054] - An electronic diagnostic unit, which is autonomous and mobile, and configured to perform automated tests to verify the internal electrical integrity of the control unit without simulating flight conditions of the engine connected to the control unit.

[0055] - A connecting member configured to connect the unit to the control unit of the aircraft engine.

[0056] The method is characterized by being performed simultaneously with the engine being hooked onto the aircraft, and includes the following steps:

[0057] - Disconnect at least one wiring harness that connects the control unit to multiple devices.

[0058] - The connecting component is inserted into the unit on one side and into the control unit on the other side, and

[0059] - Analyze the internal electrical integrity of the control unit by performing automated tests, including:

[0060] This unit transmits the adjustment parameters from the internal memory of the control unit to the control unit via a connecting component.

[0061] This unit receives responses from the control unit via a connecting component and analyzes these responses to infer the health status of the control unit.

[0062] In order to significantly reduce the NFF rate, it is necessary to perform diagnostics on the control unit before removing it, as is the case now.

[0063] The principle is not to read self-test faults or faults that occur during the read operation, but rather to specifically stimulate the control unit to compare its operation with the model. If the control unit's operation deviates from the model, it is declared that the control unit is malfunctioning.

[0064] In order to verify whether there is a fault in the accused control unit, the unit will enable internal verification of the control unit by processing the input and output excitations of the control unit by passing the adjustment parameters to the internal memory of the control unit, and enable internal measurement to verify the response based on the excitation.

[0065] According to the present invention, the excitation is performed inside the control unit, which then verifies whether the return meets expectations.

[0066] Therefore, instead of electrically simulating all sensors and actuators, this invention directly intervenes in the control unit to verify the integrity of its operation as close as possible to the control unit. This makes the device compact and thus mobile enough to be transported as close to the engine as possible, enabling maintenance operations to be performed directly on the control unit of the engine hooked to the aircraft.

[0067] The method according to the invention may include one or more of the following features and / or steps, which may be considered individually or in combination with each other:

[0068] - The disconnection step includes: disconnecting at least one first wiring harness that connects the control unit to multiple devices and a second wiring harness that connects the control unit to the engine, the at least one first wiring harness being connected to an input port of the control unit and the second wiring harness being connected to at least one output port of the control unit;

[0069] - The insertion step includes: inserting the connecting component into the input port and the at least one output port of the control unit;

[0070] The test includes two distinct verification phases: a first verification phase verifies the electrical integrity of the control unit via the input port, and a second verification phase verifies the electrical integrity of the control unit via the at least one output port.

[0071] - The first stage includes: transmitting adjustment parameters to the control unit via the input port, and measuring signals generated directly in the internal memory of the control unit and in the software interface between the control unit's operating system and application software package;

[0072] - The second stage includes: transmitting adjustment parameters to the control unit through the at least one output port, and measuring signals generated directly in the internal memory of the control unit and in the software interface between the operating system and application software package of the control unit;

[0073] - The method includes the following steps during testing: the unit transmits a physical quantity designed to suppress false faults appearing in the memory of the control unit to the control unit via a connecting member;

[0074] - The connecting component includes a single connecting cable, which has a first connecting plug at one end for connecting to the unit and a plurality of second connecting plugs at the opposite end for connecting to the control unit;

[0075] --The memory of the control unit is random access memory (RAM), which is the volatile working memory of the control unit, rather than non-volatile memory (NVM), which is the storage memory of the certified engine tuning software; this allows the memory of the certified engine control software OS / AS to be uninterrupted, as such interference could cause errors during testing. Attached Figure Description

[0076] Other features and advantages of the present invention will become apparent from the following detailed description, with reference to the accompanying drawings for understanding the following detailed description, in which:

[0077] [ Figure 1 ] Figure 1 This is a schematic perspective view of an aircraft engine equipped with a control unit.

[0078] [ Figure 2 ] Figure 2 This is a very schematic perspective view of the control and regulation unit of an aircraft engine.

[0079] [ Figure 3 ] Figure 3 yes Figure 1 A schematic perspective view of the engine and the diagnostic device according to the invention.

[0080] [ Figure 4 ] Figure 4 This is a very schematic view of the cable connecting the diagnostic device to the control unit.

[0081] [ Figure 5 ] Figure 5 This is a very schematic view illustrating the steps of the diagnostic method according to the present invention.

[0082] [ Figure 6 ] Figure 6 This is a very schematic view illustrating another step of the diagnostic method according to the invention.

[0083] [ Figure 7 ] Figure 7 This is a very schematic view illustrating another step of the diagnostic method according to the invention.

[0084] [ Figure 8 ] Figure 8 This is a very schematic view illustrating another step of the diagnostic method according to the invention. Detailed Implementation

[0085] Figure 1 This is a schematic perspective view of an engine 10 for an aircraft. In the example shown, the engine is a turbine, more precisely a turbofan engine. The engine 10 is designed to be mounted on an aircraft and can be attached under the wing or to the rear of the fuselage.

[0086] Essentially, engine 10 includes a gas generator comprising at least one compressor, an annular combustion chamber, and at least one turbine. A propeller, referred to as fan 12, is located upstream of the gas generator relative to the flow of gas within engine 10 and is surrounded by a housing 14. The housing 14 defines an annular inlet duct for an airflow through fan 12, a portion of which is intended to flow around the gas generator and a portion of which is intended to supply gas to the gas generator. This other portion of the airflow is compressed in the compressor, mixed with fuel, and burned in the combustion chamber, then expanded in the turbine to drive the rotor of the turbine, as well as the rotor of the compressor and fan 12, to rotate.

[0087] The engine 10, and in particular the housing 14, is intended to be surrounded by a nacelle (not shown) that defines an annular space around the housing 14 for mounting a number of components.

[0088] Among these components is the regulation control unit 16 of the engine 10, which is the main control unit of the engine and can be considered the brain of the engine 10. This control unit, of the Digital Engine Control Unit (DECU) or Full Authority Digital Engine Control (FADEC) type, has several functions, such as:

[0089] - Adjust the fuel supply flow rate to the combustion chamber.

[0090] - Automatic engine start-up,

[0091] -Instruments that transmit engine parameters to the aircraft's cockpit.

[0092] -Manage thrust and protect operational limits,

[0093] -Management counterforce,

[0094] -wait.

[0095] The control unit 16 is connected to various devices in the engine 10 via electrical wiring harness 18, such as actuators 20 and sensors 22. Actuators 20 may include, for example, a control actuator for the variable pitch blades of the compressor, an exhaust valve control actuator, or an actuator for the thrust reverser. Sensors 22 may include, for example, temperature sensors, pressure sensors, and position sensors.

[0096] like Figure 2 As schematically shown, the control unit 16 has, for example, a generally parallelepiped shape and includes an electrical input port 16a and an electrical output port 16b. These ports 16a and 16b are connected to the aforementioned devices via a wiring harness 18, which includes a connector at its end for connecting to both ports 16a and 16b and the aforementioned devices.

[0097] As mentioned above, this type of control unit 16 requires regular maintenance to verify its health status and thus its normal operation.

[0098] The present invention relates to a diagnostic apparatus and method for diagnosing a control unit 16, the advantage of which is that the diagnostic can be performed without prior disassembly of the control unit 16, thus the control unit is intended to remain on the engine 10.

[0099] Therefore, in practice, it should be understood that the operator only needs to remove the cabin or at least the cover of the cabin to access the control unit 16 and perform maintenance and diagnostics on the control unit 16. This operation can be performed directly under the wings of the aircraft or at the rear of the fuselage, which is particularly advantageous because such operations limit the time the aircraft spends on the ground.

[0100] Figure 3 A method for diagnosing the control unit 16 by means of the diagnostic device 24 according to the invention is shown.

[0101] The device 24 includes an electronic diagnostic unit 26, a connection member 28 for connecting the unit 26 to the control unit 16, and an optional portable computer system 30.

[0102] System 30 is, for example, a telephone of the type of computer, tablet or smartphone, and is advantageously configured to communicate with unit 26 via a wireless link (e.g., via a WIFI network).

[0103] System 30 may include software or application for controlling unit 26 to perform automated tests, and a screen for displaying the results of these tests.

[0104] Unit 26 is autonomous and mobile, and is configured to execute:

[0105] Automated continuity testing and / or electrical insulation testing of electrical connectors, and determination of the health status of these connectors based on the test results, and / or

[0106] Automatic testing is performed to verify the internal electrical integrity of control unit 16 without simulating the control unit.

[0107] In the example shown, unit 26 is in the form of a suitcase 32, which has a closed lid 34 and at least one handle 36, and may also have wheels 37.

[0108] Unit 26 includes a signal generation module, a signal acquisition module, a data generation module, a data acquisition module, at least one data storage device, a data processing module, and a data communication module.

[0109] In a preferred embodiment of the invention, unit 26 is configured to measure the impedance value, compare the measured value with the theoretical value pre-stored in the unit, and transmit a signal based on the comparison result.

[0110] like Figure 3 As shown, the connecting member includes a single connecting cable 38, which includes a first connecting plug 38a at one end for connection to unit 26, and a plurality of second connecting plugs 38b at the opposite end for connection to control unit 16 and / or engine 10, which are intended to be connected to elements of unit 26.

[0111] In the example shown, cable 38 includes a first segment with a single branch. 40a and a second segment 40b having multiple parallel branches 40b1, 40b2, ..., 40n, wherein the branches of the first segment 40a are equipped with a first plug 38a at their ends opposite to the second segment 40b, and the branches 40b1, 40b2, ..., 40n of the second segment 40b are equipped with a second plug 38b at their ends opposite to the first segment 40a.

[0112] Figure 4 This is a schematic view of cable 38, and shows a connector 38a for connecting to unit 26, and a connector 38b for connecting to control unit 16 and various elements formed by wiring harness 18 and multiple devices (actuator 20 and sensor 22).

[0113] The first segment 40a has a length L1, and the second segment 40b has a maximum length L2. Preferably, L1 > k * L2, where k is at least 1, preferably at least 2. In other words, as Figure 3As shown, the length of the first segment 40a is greater than the length of the second segment 40b. Furthermore, advantageously, at least some of the branches 40b1, 40b2, ..., 40n of the second segment 40b have different lengths L2, L2'. These length differences between the segments and branches of the cable 38 make it easier to manipulate the cable and limit the risk of incorrect connection. In particular, the length differences of branches 40b1, 40b2, ..., 40n are calculated based on the positions of the input port 16a and output port 16b of the control unit 16 and based on the multiple devices to be connected to the control unit, to ensure error prevention during these connections.

[0114] One of the functions of device 24 may be to perform automatic continuity testing and / or electrical insulation testing of electrical connectors, and to determine the health status of these connectors based on the test results.

[0115] In this case, the diagnostic method includes the following steps:

[0116] - Disconnect at least one wiring harness 18 that connects the control unit 16 to multiple devices.

[0117] - The connecting member 28 is inserted into the unit 26 on one side and into the wiring harness 22 and / or multiple devices on the other side, and

[0118] -Analyze the health status of wire harness 22 and / or multiple devices by performing automated continuity tests and / or electrical insulation tests on the electrical connectors of wire harness 22 and / or multiple devices.

[0119] In a preferred embodiment, each test in the test includes: measuring the impedance value, comparing the measured value with a theoretical value pre-stored in the cell, and transmitting a signal based on the comparison result.

[0120] like Figure 5 As schematically shown, a continuity test is performed by plugging the connecting member 28 into a single port of the unit 26 and into the wiring harness 22 and / or the plugs of the devices (actuator 20 and sensor 22).

[0121] The test is performed automatically by switching between different electrical connectors of the wiring harness / sensor / actuator to be tested. This switching is programmed, and the resulting measurement is the impedance that must be returned from a table of theoretical values, which is programmed based on what is being tested.

[0122] In this way, the unit tests all these connectors by connecting all the connectors that typically come from the wiring harness / sensor / actuator in the insertion control unit to the unit.

[0123] Because the measurements are automated, each measurement takes only a few seconds, eliminating the risk of mishandling that would distort the measurements, much like how measurements are performed manually today with multimeters and aircraft mechanics.

[0124] Therefore, the present invention enables the elimination of the possibility of error handling, increases the reliability of measurement, and accelerates the process by automatically performing measurements once the harness / sensor / actuator is connected to the unit via the connecting member.

[0125] The measured continuity is actually impedance, which is converted into voltage, current and / or resistance measurements in the cell.

[0126] like Figure 6 As schematically shown, insulation tests are performed by plugging connection members 28 into a single port of unit 26 and into the plugs of wiring harness 22 and / or multiple devices (actuator 20 and sensor 22), including grounding socket 42 connected to the metal housing of the engine (such as the aforementioned housing 14).

[0127] In the same manner as each of the continuity tests described above, each insulation test can also be performed manually and pin-by-pin on each device connector and / or wiring harness connected to the control unit; however, the present invention recommends performing each insulation test directly and automatically.

[0128] The unit then automatically performs switching between different electrical connectors of the wire harness / sensor / actuator whose insulation is being tested. This switching is programmed into the unit, and the resulting measurement is the impedance that must be returned from a table of theoretical values, which is programmed based on what is being tested.

[0129] In theory, the ideal is that the insulation is an infinite impedance in ohms. In practice, a finite and very large programmed value, depending on the measurement, is programmed into the cell according to the specific circumstances.

[0130] In this way, the unit tests all these connectors by connecting all the connectors that typically come from the sensors / actuators in the insertion control unit to the unit.

[0131] Because the measurements are automated, each measurement takes only a few seconds, eliminating the risk of mishandling that would distort the measurements, much like how measurements are performed manually today with multimeters and aircraft mechanics.

[0132] Therefore, the present invention enables the elimination of the possibility of error handling, increases the reliability of measurement, and accelerates the process by automatically performing measurements once the harness / sensor / actuator is connected to the unit via the connecting member.

[0133] Compared to the pre-defined conformity table for each test case, insulation is the transformation of a circuit with high impedance.

[0134] One of the functions of device 24 is to perform automated tests to verify the internal electrical integrity of control unit 16 without simulating the control unit.

[0135] In this case, the diagnostic method includes the following steps:

[0136] - Disconnect at least one wiring harness that connects the control unit to multiple devices.

[0137] - The connecting component is inserted into the unit on one side and into the control unit on the other side, and

[0138] - Analyze the internal electrical integrity of the control unit by performing automated tests, including:

[0139] This unit transmits the adjustment parameters from the internal memory of the control unit to the control unit via a connecting component.

[0140] This unit receives responses from the control unit via a connecting component and analyzes these responses to infer the health status of the control unit.

[0141] Advantageously, the disconnection step includes: disconnecting at least one first wiring harness that connects the control unit to multiple devices and a second wiring harness that connects the control unit to the engine, the at least one first wiring harness being connected to an input port of the control unit and the second wiring harness being connected to at least one output port of the control unit.

[0142] The insertion step preferably includes: inserting the connecting member into the input port and the at least one output port of the control unit.

[0143] According to a preferred embodiment of the present invention, the test includes two different verification phases: a first verification phase for verifying the electrical integrity of the control unit via an input port, and a second verification phase for verifying the electrical integrity of the control unit via the at least one output port.

[0144] like Figure 7 As shown, the first stage includes: transmitting adjustment parameters to the control unit 16 via input port 16a, and measuring signals generated directly in the internal memory of the control unit and in the software interface between the control unit's operating system and application software package.

[0145] This unit injects a defined signal via a cable to simulate the physical quantities of the sensor / actuator under test and verifies whether the expected regulation function based on the simulated input is consistent with the expected regulation function.

[0146] The measurements performed in the control unit are conducted internally, within the internal loop of the signals. These tests utilize simulations connected to external parts of the control unit, but the measurements are performed internally via a software interface directly to the memory registers and the control unit's operating system and application software packages. This provides a true picture of the control unit's internal operating (or fault) state.

[0147] Furthermore, to prevent false faults from being generated in the control unit's memory, false fault suppression can be induced by scanning the current / voltage / impedance of the expected physical quantities of the control unit. This allows the control unit to be restored to the same state as before the test.

[0148] like Figure 8 As shown, the second stage includes: transmitting adjustment parameters to the control unit through the at least one output port, and measuring signals generated directly in the internal memory of the control unit and in the software interface between the control unit's operating system and application software package.

[0149] The output test uses the same principles as the input test.

[0150] This unit injects a defined signal via a cable to simulate the physical quantities of the sensor / actuator under test and verifies whether the expected regulation function based on the simulated output is consistent with the expected regulation function.

[0151] The measurements performed in the control unit are conducted internally, within the internal loop of the signals. These tests utilize simulations connected to external parts of the control unit, but the measurements are performed internally via a software interface directly to the memory registers and the control unit's operating system and application software packages. This provides a true picture of the control unit's internal operating (or fault) state.

[0152] Furthermore, to prevent false faults from being generated in the control unit's memory, false fault suppression can be induced by scanning the current / voltage / impedance of the expected physical quantities of the control unit. This allows the control unit to be restored to the same state as before the test.

Claims

1. A method for diagnosing an engine control unit (16) of an aircraft using a diagnostic device (24), said diagnostic device comprising: - An electronic diagnostic unit (26), which is autonomous and mobile and configured to perform automated tests to verify the internal electrical integrity of the engine control unit without simulating the flight conditions of the engine connected to the engine control unit. - A connecting member (28) configured to connect the electronic diagnostic unit to the engine control unit of the aircraft. The method is characterized in that it is performed simultaneously with the engine being hooked onto the aircraft, and includes the following steps: - Disconnect at least one wiring harness (18) that connects the engine control unit to multiple devices. - The connecting member (28) is inserted into the electronic diagnostic unit (26) on one side and into the engine control unit (16) on the other side, in place of the disconnected at least one wiring harness, and - Analyze the internal electrical integrity of the engine control unit by performing automated tests, including: The electronic diagnostic unit transmits the adjustment parameters from the internal memory of the engine control unit to the engine control unit via the connecting member. The electronic diagnostic unit receives the response from the engine control unit generated by the transmission of adjustment parameters via the connecting member, and analyzes these responses to infer the health status of the engine control unit. The method further includes the following steps during testing: the electronic diagnostic unit (26) transmits a physical quantity intended to suppress false faults appearing in the memory of the engine control unit (16) to the engine control unit (16) via the connection member (28).

2. The method according to claim 1, wherein, The disconnection step includes: disconnecting at least one first wiring harness that connects the engine control unit (16) to multiple devices and a second wiring harness that connects the engine control unit to the engine (10), the at least one first wiring harness being connected to an input port (16a) of the engine control unit and the second wiring harness being connected to at least one output port (16b) of the engine control unit.

3. The method according to claim 2, wherein, The insertion step includes: inserting the connecting member (28) into the input port (16a) and the at least one output port (16b) of the engine control unit (16).

4. The method according to claim 3, wherein, The test includes two distinct verification phases: a first verification phase for verifying the electrical integrity of the engine control unit (16) via the input port (16a), and a second verification phase for verifying the electrical integrity of the engine control unit via the at least one output port (16b).

5. The method according to claim 4, wherein, The first verification phase includes: transmitting adjustment parameters to the engine control unit (16) through the input port (16a), and measuring signals generated directly in the internal memory of the engine control unit and in the software interface between the operating system and application software package of the engine control unit.

6. The method according to claim 4 or 5, wherein, The second verification phase includes: transmitting adjustment parameters to the engine control unit (16) through the at least one output port (16b), and measuring signals generated directly in the internal memory of the engine control unit and in the software interface between the operating system and application software package of the engine control unit.

7. The method according to any one of claims 1 to 5, wherein, The connecting member (28) includes a single connecting cable (38), which includes a first connecting plug (38a) at one end for connection to the electronic diagnostic unit and a plurality of second connecting plugs (38b) at the opposite end for connection to the engine control unit.

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