IMPROVED METHOD FOR ORGANIZING AIRCRAFT MAINTENANCE

Abstract

The present invention relates to a method for managing aircraft maintenance by defining a recommended aircraft maintenance program, said recommended maintenance program determining maintenance deadlines using primary data from the design and flight tests of the various equipment and / or elements of the aircraft, characterized in that it consists of: - using and recording actual aircraft usage data, - using computing means to recalculate maintenance deadlines using at least one algorithm, based on actual usage data, - and updating the recommended maintenance program.

Description

Improved method for organizing aircraft maintenance. The present invention relates to the general technical field of maintenance of devices or aircraft, and in particular helicopters. The present invention relates in particular to the planning of maintenance operations and the creation of recommended maintenance programs for aircraft. Currently, aircraft maintenance is determined, for example, during its design phase. Maintenance is then described in a recommended maintenance program (RMP) where maintenance intervals are calculated based on a theoretical aircraft usage covering a maximum number of critical behaviors. This theoretical usage is identical for all aircraft of the same type, regardless of their actual operation by the purchaser. Such a situation can lead to additional maintenance costs, particularly for aircraft with low usage. The customer's actual usage is not taken into account in existing recommended maintenance programs. Furthermore, the monitoring systems integrated into the equipment do not provide information on estimating wear or damage to the monitored parts over time. Moreover, existing recommended maintenance schedules reflect both the increasing complexity of the machines and the growing number of specific maintenance tasks. Maintenance management is becoming increasingly complicated for the operator. The object of the present invention is therefore to remedy the aforementioned drawbacks and to propose a new maintenance management method, facilitating the planning of interventions for operators. Another object of the present invention is to provide a new maintenance management method that takes into account the actual and individualized use of each device. Another object of the present invention is to provide a new maintenance management method that allows for the real-time estimation of the remaining service life of a device's components. A further object of the present invention is to provide a new maintenance management method that reduces aircraft maintenance costs. The objectives of the invention are achieved by means of a method for managing the maintenance of at least one aircraft by defining a recommended aircraft maintenance schedule. This recommended maintenance schedule determines maintenance intervals using primary data from the design and flight testing of the various aircraft equipment and / or components. The method is characterized in that it consists of: using and recording data on the aircraft's actual use; using computing means to recalculate maintenance intervals using at least one algorithm, based on the actual use data; and updating the recommended maintenance schedule. In one embodiment, the method according to the invention consists of updating the recommended maintenance schedule in real time or after each actual use of the aircraft.According to one embodiment, the method according to the invention consists of determining the influential degradation parameters, representative of the aircraft's degradation modes, and monitoring said degradation parameters. According to another embodiment, the method according to the invention consists of using, as actual usage data, usage and health data recorded by onboard aircraft monitoring systems. Usage and health data are, for example, divided into five categories, including: - data relating to loads representing the torques and moments applied to the aircraft's mechanical components; - data relating to the lubrication of mechanical parts, such as measurements of the oil's lubricating power and degree of oil contamination; - data relating to the environment, such as climate, temperature, pressure, and altitude; - data relating to flight phases, including aerodynamic forces and vibrations; - and operational feedback data relating to the health of an aircraft or a fleet of aircraft. According to one implementation example, the method according to the invention consists of determining threshold values ​​for the influential degradation parameters and verifying during the life cycle whether these thresholds are exceeded by said parameters.According to one embodiment, the method according to the invention consists of determining a potential maintenance credit granted to the user, based on the conclusions of the analysis of influential degradation parameters. According to another embodiment, the method according to the invention consists of using and analyzing recorded usage and condition data to monitor the degradation patterns of the various components or equipment of the aircraft, particularly mechanical parts, and to determine a level or percentage of wear of said components or equipment and / or information relating to their remaining service life. According to another embodiment, the method according to the invention consists of monitoring degradation patterns using at least one predefined calculation model, for example, during the aircraft design phase, to analyze usage and condition data.According to one example of implementation, the method according to the invention consists of using a damage calculation model and a damage accumulation calculation model for the mechanical parts constituting the aircraft. According to one example of implementation, the method according to the invention consists of using input values ​​recorded in real time and derived from usage and health data to recalculate the wear or damage of parts using the damage calculation model.The objects assigned to the present invention are also achieved using a monitoring, computing and decision unit for a helicopter-type aircraft and for implementing the aforementioned method, comprising: - a set of sensors enabling the capture of input parameters necessary for the dynamic calculation of maintenance deadlines, - computing means, such as a microcontroller, for hosting on the ground or on board one or more algorithms integrating one or more calculation models such as dynamic calculation algorithms for deadlines, - recording means, for example connected to the microcontroller, to the sensors and / or to other sources of information for recording usage and health data, - and means for formatting usage and health data capable of generating on the ground or on board a recommended dynamic and updated maintenance program.According to an embodiment of the invention, the computing and decision monitoring unit is associated with transmission means for transmitting usage and health data and / or the updated recommended maintenance program to at least one fixed ground base. According to one embodiment, the monitoring, computing and decision unit according to the invention comprises, on the one hand, in the form of an on-board black box, the recording means and, on the other hand, a ground-based data processing station. The objects assigned to the invention are also reached using a helicopter equipped with a monitoring, computing, and decision-making unit as described above. The method according to the invention has the advantage of being customized for each aircraft and generating a recommended dynamic maintenance program based on the actual use of each aircraft. The method according to the invention has the advantage of maximizing the automation of maintenance task planning, thanks to a recommended dynamic maintenance program that is updated over time based on the aircraft's actual use. The method according to the invention has the advantage of optimizing the use of parts and increasing their potential, fully utilizing their properties and qualities.Another advantage is that the recommended dynamic maintenance program allows takeoff and mission execution even when damage or wear to parts is not yet critical, while the maintenance schedule's service life potential has been exceeded. The method according to the invention also optimizes spare parts inventory management. Another advantage is that the recommended dynamic maintenance program can predict the occurrence of damage to a part that will therefore wear out prematurely, for example, due to specific aircraft usage patterns. This allows for mandatory maintenance for safety purposes, and this maintenance can be implemented before the scheduled maintenance interval initially defined in the recommended maintenance program. Another advantage of the method according to the invention lies in a reduction of aircraft unavailability for unnecessary maintenance operations and consequently in a reduction of the operating costs of the aircraft as well as of an entire fleet. The invention and its advantages will become apparent in more detail in the following description with examples of implementation given by way of illustration with reference to the attached figures which represent: - figure 1, schematically illustrates an example of implementation of the method according to the invention to establish a recommended maintenance program, - figure 2, schematically illustrates examples of data processing steps enabling, in the establishment of a recommended maintenance program, to provide information on the residual reliability of a part or equipment, - and figure 3 schematically illustrates an example of implementation of a monitoring, calculation and decision unit according to the invention. The method according to the invention and illustrated in Figure 1 allows for the management of aircraft maintenance by defining a recommended maintenance program (RMP) for the aircraft. The RMP determines maintenance schedules using primary data from component design and flight tests of the various aircraft equipment and / or elements. The method according to the invention consists of using and recording actual aircraft usage data. This data relates to usage and flight parameters. The method according to the invention uses computing means to recalculate the maintenance schedules using at least one algorithm, based on the actual usage data, and updates the RMP. This results in a dynamic RMP.The method according to the invention preferably consists of updating the recommended maintenance program (PRE) in real time or after each actual use of the aircraft. The method according to the invention consists of determining the 20 influential degradation parameters, representative of the aircraft's degradation modes, and monitoring said degradation parameters using actual aircraft usage data. Within the framework of the method according to the invention, usage and health data recorded, for example, by onboard aircraft monitoring systems, are used as actual usage data.Usage and health data are, for example, divided into five categories presented below, including: - data relating to loads representing the torques and moments applied to the aircraft's mechanical components; data relating to the lubrication of mechanical parts, such as measurements of the oil's lubricating power and degree of oil contamination; - data relating to the environment, such as climate, temperatures, pressures, and altitudes; - data relating to flight phases, including aerodynamic forces and vibrations; - and operational feedback data relating to the health of an aircraft or a fleet of aircraft. The method according to the invention consists, in one example of implementation, of determining threshold values ​​for influential degradation parameters and verifying, during the life cycle, whether these thresholds have been exceeded by one or more influential degradation parameters.The identification of such exceedances will influence the updating of the recommended dynamic maintenance plan. The method according to the invention can also consist of determining a potential maintenance credit granted to the user based on the conclusions of the analysis of influential degradation parameters. Maintenance operations can thus be postponed without increasing the risk of malfunctions or breakdowns. The method according to the invention consists of using and analyzing recorded usage and health data in order to track the degradation patterns of the various components or equipment of the aircraft, particularly mechanical parts, and to determine a level or percentage of wear of said components or equipment and / or information relating to the remaining service life of said components or equipment.The method according to the invention also consists of monitoring degradation modes using at least one predefined calculation model, for example during aircraft design, to analyze usage and health data. The method uses a damage calculation model and a damage accumulation calculation model for the aircraft's constituent mechanical parts. The method according to the invention uses real-time input values ​​from usage and condition data to recalculate the wear or damage of the parts using the damage calculation model. The algorithms that can be used to perform these calculations are based on an understanding of all the degradation modes existing within dynamic systems, such as those of a helicopter. The method according to the invention makes it possible to obtain and update the time between each maintenance, known as the "Time Between Overhaul" (TBO). For extending these times, updating and calculating the TBO preferably involves several algorithms.Each algorithm represents a given degradation mode, and each part constituting the mechanical assembly subject to this degradation mode is listed. The algorithm in question takes into account the design of the part (shape, material, mechanical clearance, surface finish, etc.), its use (corresponding to the function it performs), and the stresses it undergoes (torque, lubrication, or other stresses appearing in the four families listed above). Each degradation mode is thus conceptualized by an algorithm based on a mathematical and / or physical law, a threshold, expert opinion, a statistical reliability law, or other factors. Referring, for example, to Figure 2, it is clear that the inputs of such an algorithm are the data relating to the design of the part and the data relating to usage and flight parameters, namely data relating to the environment external to the part, recorded in real time. The output of such an algorithm is, for example, information on the volume of wear, the percentage of damage, or the remaining reliability corresponding to a remaining service life. The calculation methods correlate, for example, a set of physical laws for modeling contacts between parts, known to the scientific community.with the aim of calculating remaining lifespan potential and deducing a new deadline or an increase in flight hours. The algorithms can be classified into three categories, namely: - threshold-based algorithms, which rely on trend tracking of one or a correlation of influential parameters using historical data compiled in a database; these algorithms plot a curve over the entire historical period, and if the curve exceeds a given threshold, wear information is then available; - model-based algorithms based on physical mechanics, which rely on a physical understanding of the degradation mode; for example, the contact forces between two gear teeth are modeled by physical laws (Hertzian pressure), allowing the calculation of a gear endurance limit; these algorithms relate more specifically to modeling wear beyond the endurance limit; and - reliability-based statistical algorithms.By diverting known reliability laws to predict the occurrence of a phenomenon or a mode of degradation, statistical laws thus become dynamic according to continuously recorded parameters (Weibull and Cox laws, for example). The present invention also relates to a monitoring, calculation, and decision unit 1 for a helicopter-type aircraft, implementing the method according to the invention. The monitoring, calculation, and decision unit 1 according to the invention comprises a set of sensors C1, C2, C3 for capturing input parameters necessary for the dynamic calculation of maintenance schedules. The monitoring, calculation, and decision unit 1 also comprises computing means 10, such as a microcontroller, for hosting, either on the ground or onboard, one or more algorithms incorporating one or more calculation models such as dynamic schedule calculation algorithms. The monitoring, calculation, and decision unit 1 also comprises recording means 20, for example, connected to the microcontroller, to sensors C1, C2, C3, and / or to other information sources for recording usage and condition data.The monitoring, computing, and decision-making unit 1 also includes means for formatting usage and health data 30, capable of generating a dynamic and updated recommended maintenance program (PRE) either on the ground or onboard. These formatting means 30 are, for example, integrated into a ground-based data processing station. They can also be onboard. The monitoring, computing, and decision-making unit 1 according to the invention is, for example, associated with communication or transmission means for transmitting usage and health data and / or the updated recommended maintenance program (PRE) to at least one fixed ground base and / or the customer operating the aircraft. This transmission can be carried out via an internet portal. Transmission of aircraft usage and health data to the formatting means or to the ground computing means via a wireless link can also be envisaged. As an example, recorded data is stored in the aircraft's internal memory during flight, then unloaded to a ground-based system when the machine is stopped using communication methods such as memory cards, wireless links, or other means. This raw data, or data that is fully or partially formatted, is then analyzed and added to a database that includes all data downloads made since the aircraft was put into service. The monitoring, computing and decision unit 1 includes, for example, on the one hand, in the form of an on-board black box, the recording means and the sensors Cl, C2, C3 and on the other hand, a ground-based data processing station or a server. Naturally, the present invention is subject to numerous variations in 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 or a described step with an equivalent step, without departing from the scope of the present invention.

Claims

CLAIMS 1. A monitoring, computing, and decision-making unit (1) for a helicopter-type aircraft, implementing a method for managing the maintenance of at least one aircraft by defining a recommended aircraft maintenance schedule, said recommended maintenance schedule determining maintenance deadlines using primary data from the design and flight tests of the various equipment and / or components of the aircraft, said method consisting of: - using and recording actual aircraft usage data, using computing means to recalculate maintenance deadlines using at least one algorithm, based on actual usage data, and updating the recommended maintenance schedule, characterized in that it comprises: a set of sensors (C1, C2, C3) enabling the capture of input parameters necessary for the dynamic calculation of maintenance deadlines, computing means (10),of the microcontroller type, to host on the ground or onboard one or more algorithms integrating one or more calculation models of the type dynamic calculation algorithms of deadlines, 20 25 recording means (20), for example connected to the microcontroller, to sensors (Cl, C2, C3) and / or to other sources of information to record usage and health data, and means for formatting (30) the usage and health data capable of editing on the ground or onboard a recommended maintenance program (PRE) dynamic and updated.

2. Monitoring, calculation and decision unit (1) according to claim 1, characterized in that it is associated with transmission means for transmitting usage and health data and / or the updated PRE recommended maintenance program to at least one fixed base on the ground.

3. Monitoring, computing and decision unit (1) according to claim 1 or 2, characterized in that it comprises on the one hand in the form of an on-board black box the recording means and on the other hand a ground-based data processing station.

4. Monitoring unit according to any one of claims 1 to 3, characterized in that said method consists of updating the recommended maintenance program in real time or after each actual use of the aircraft.

5. Monitoring unit according to any one of the preceding claims, characterized in that said method consists of determining the influential degradation parameters, representative of the aircraft degradation modes and of monitoring said degradation parameters.

6. Monitoring unit according to claim 5, characterized in that said method consists of using, as actual usage data, usage and health data recorded by on-board aircraft monitoring systems.

7. Monitoring unit according to claim 6, characterized in that the usage and health data are divided into five families comprising: - data relating to loads representing the torques and moments applied to the mechanical elements of the aircraft, - data relating to the lubrication of mechanical parts, such as measurements of the lubricating power of the oil and degree of oil contamination, - data relating to the environment such as climate, temperatures, pressures and altitudes, - data relating to flight phases, including aerodynamic forces and vibrations, - and feedback data relating to the health of an aircraft or a fleet of aircraft.

8. Monitoring unit according to any one of claims 5 to 7, characterized in that said method consists of determining threshold values ​​for influential degradation parameters and verifying during the life cycle whether these thresholds are exceeded by said parameters.

9. Monitoring unit according to any one of claims 5 to 8, characterized in that said method consists of determining a possible maintenance credit granted to the user based on the conclusions of the processing of influential degradation parameters.

10. Monitoring unit according to claim 6 or 7, characterized in that said method consists of using and analyzing recorded usage and health data, to monitor the degradation modes of the various elements or equipment constituting the aircraft, in particular mechanical parts, and to determine a level or percentage of wear of said elements or equipment and / or information relating to the remaining life potential of said elements or equipment.

11. Monitoring unit according to claim 10, characterized in that said method consists of tracking degradation modes using at least one predefined calculation model, for example during aircraft design, to analyze usage and health data.

12. A monitoring unit according to claim 11, characterized in that said method consists of using a damage calculation model and a damage accumulation calculation model for the mechanical components of the aircraft. A monitoring unit according to claim 12, characterized in that said method consists of using real-time recorded input values ​​from usage and health data to recalculate the wear or damage of the parts using the damage calculation model.

14. A helicopter comprising a monitoring, calculation (1), and decision unit according to any one of claims 1 to 13.