Abstract:As the material base of integrated logistic support (ILS), scientific prediction and reasonable configuration of spare parts can effectively ensure the safe and economic operation of civil aircraft. To achieve all-win results for stakeholders (manufacturers, operators, repairers, etc.), this paper conducts a comprehensive investigation on the prediction and configuration management technologies for civil aircraft spare parts, and discusses its development trend in future. Firstly, the research status for the prediction technologies of civil aircraft spare parts is introduced. Secondly, the research status for the configuration management methods is explored of civil aircraft spare parts. Finally, the development trend of civil aircraft spare parts prediction and configuration management technology is studied based on the advantages and disadvantages of the existing methods. The aim of this paper is to provide a reference for the comprehensive management of domestic civil aircraft spare parts, and to support the improvement and perfection of the maintenance support system of civil aircraft.

Abstract:Transfer learning is a method to solve problems in a given field by using the existing knowledge in other related fields. It can effectively suppress the impact of data loss on the accurate establishment of state evaluation model, so as to lay a foundation for safe and reliable operation of equipment and maintenance decision. This paper summarizes the current research situation of using transfer learning to realize running state evaluation in the absence of device product data and discusses the future research direction of transfer learning in the field of state evaluation.

Abstract:In view of the impact of health and use monitoring system (HUMS) is not fully considered in the traditional MSG-3-based civil helicopter maintenance program analysis, as well as the problems of inadequacy and disadvantages exposed during operation, this paper innovatively studies the influence of HUMS on the maintenance task of civil helicopter, and comprehensively analyzes the impact of HUMS on the maintenance tasks of systems/powerplant, structural, zonal and L/HIRF, under the overall analysis framework of MSG-3, putting forward a set of MSG-3 maintenance task analysis suggestions considering HUMS technology, which can provide key technical support for the development of a new generation of civil helicopter maintenance program in China.

Abstract:In the aerospace system, there are many reliability parameters to describe the reliability characteristics of products, but most of them are based on continuous reliability parameters in continuous time, and there are fewer descriptions of discrete reliability parameters that are defined as reliability parameters in discrete time, such as discrete failure probability. In order to make up for the shortcomings of reliability theory in this aspect, the mathematic relationship of discrete reliability parameters are studied from the perspective of discrete time, including the mathematical conversion formula of discrete failure probability and discrete failure rate, the mathematical of calculating discrete reliability by discrete failure rate, and the mathematical conversion formula of mean work times to failures and discrete failure probability. These works can provide the mathematical theory basis for the conversion calculation of reliability parameters and indicators.

Abstract:Line Replaceable Unit (LRU) is treated as a unit for fast fault detection and real-time replacement, which can effectively avoid the phenomenon of aircraft on ground (AOG) during operation, and improve maintenance efficiency. Under the condition of meeting the continuous airworthiness requirements, the safety and reliability of civil aircraft can be ensured. To reasonably and effectively derive LRU division of civil aircraft, Based on the comprehensive consideration of many factors in the stage of design and operation process of civil aircraft, this paper proposes a LRU division method, namely two-step iterative analytical hierarchy process (TSI-AHP, short for), on the premise of considering the influence of various factors in the design stage and operation process of civil aircraft. Firstly, the influence of relevant factors in the design and operation stages on LRU division of civil aircraft is investigated. Secondly, the influence of various factors are comprehensive considered, and the lowest structures of product decomposed by their function are regarded as the study objects, and the TSI-AHP is applied to implement LRU division of civil aircraft. Finally, the landing gear system of ARJ21-700 aircraft is treated as an example to realize the LRU division using the method proposed. The analytical shows that the proposed TSI-AHP can effectively accomplish the LRU division for the landing gear system of ARJ21-700 aircraft, and the effectiveness and applicability of the method for LRU division are verified compared with the data in engineering practice. The efforts of this paper provide an effective guidance for LRU division of domestic civil aircraft.

Abstract:In order to evaluate the removal and installation time of airborne equipment, this paper presents an evaluation method based on maintenance ergonomics analysis and process simulation models. Decomposed the disassembly and installation process into basic maintenance activities, created process simulation models; Use MODAPTS evaluate basic maintenance activities time; Use coefficient to correct basic maintenance activities time, the coefficient is determined by the comprehensive assessment results of maintenance complexity and maintenance ergonomics analysis ; Evaluate the disassembly and installation time according to basic maintenance activities time and maintenance work process analysis. Verify the method by a case of evaluating engine removal time. The result shows that, the method presented in this paper can be used to accurately evaluate the removal and installation time of airborne equipment.

Abstract:Since there widely existing random uncertainty in engineering structure, an efficient dynamic reliability analysis method which simultaneously considers the uncertainties of dynamic excitation load and material properties parameters is proposed. The Kriging surrogate model between the uncertainty material properties parameters and conditional dynamic reliability is firstly constructed, and then the analytical expression of the final dynamic reliability is derived based on the constructed surrogate model. Simultaneously, a new learning function for constructing the adaptive Kriging surrogate is proposed. The proposed method for estimating the dynamic reliability can not only avoid the error caused by numerical integration with surrogate model, but also provide accurate solution of dynamic reliability by using the computational costs as little as possible. The accuracy and efficiency of the proposed method is demonstrated by employing the dynamic reliability analysis of ceramic matrix composites aircraft skin frame structure under the random uncertainties of dynamic excitation load and material properties parameters.

Abstract:Abstract As a safety analysis method based on STAMP model, the STPA method shows strong capability and advantages for safety analysis of complex systems. The analysis STPA process and ARP-4761 was compared, and the conformity of STPA to GJB900A-2012 general requirements for equipment safety work was analyzed, which reflects the great advantages and applicability of STPA method. In order to solve the problems found in STPA’s safety analysis, some improvement measures are proposed in building functional control structure, identifying unsafe control behaviors and analyzing causes. The conclusion and proposed method can provide the theoretical and process guidance which is in line with the high-tech characteristics of modern aircraft and worthy of reference for the system-level safety design of complex aviation products and even military aircraft.

Abstract:The tactical performance and advantages of unmanned aerial vehicle (UAV) system will play an increasingly important role in future high-tech warfare and civil aviation. However, due to the different characteristics of manned and unmanned aerial vehicle flight accidents, the safety analysis and management measures of manned aerial vehicle are not suitable for UAV system. Therefore, the safety and hazard analysis of UAV system is carried out to construct the UAV security management framework. Firstly, according to the statistical analysis of UAV system flight accidents, the characteristics of UAV system accidents are concluded. And then the safety of UAV system is defined, the classification of severity and its corresponding acceptability for UAV system are presented. Finally, hazard analysis is carried out from design, crew training and operation fields.

Abstract:In order to study the reliability of the aircraft hatch lock mechanism closing system, this paper choose an aircraft hatch lock mechanism as an example, establishes the simulation model of the mechanism through LMS, and studies the maximum hydraulic pressure failure and the time-failure modes during the closing process of the lock mechanism. Considering the correlation between the two failure modes, based on the important sampling method and B-P neural network method, the reliability of the aircraft hatch lock mechanism with multiple failure modes is calculated. Comparing the simulation results of these two methods with the results of the traditional Monte Carlo method, we can conclude that the above two methods for calculating the reliability of the aircraft door lock mechanism are reasonable, and the error range is within 3%. The computational efficiency of the two methods is improved compared with the traditional methods. Among them, the BP neural network method is more accurate and efficient than the important sampling method, and is more suitable for studying the reliability of the aircraft door lock mechanism.

Abstract:In order to ensure the safe operation of emergency flotation system for helicopters and trigger reliably in the process of impacting on water, the reliability of sensor module, the key component of the system, is analyzed. Based on the systematic understanding of k/n(G) voting system composed of different types of units, Monte Carlo simulation platforms of sensor module under different logic relations are built by using Matlab/Simulink, and the corresponding simulation & theoretical calculation are carried out. The results show that it is feasible and effective to apply Monte Carlo method to reliability analysis of sensor module. According to the results of functional hazard analysis and reliability analysis, the 3/5 voting system is more suitable for the sensor module of the helicopter emergency flotation system. This provides a technical route for the logical relationship selection and reliability design of similar modules.

Abstract:Complicated calculation process and low calculation efficiency are main challenges for reliability analysis of complex structures assembled from multiple components. Moving extremum response surface method-based decomposed coordinative strategy (DCMERSM, short for) is proposed based on extremum response surface method, moving least squares and decomposition coordinative strategy, which is used to accomplish dynamic reliability analysis of multi-component structures. In this paper, the dynamic reliability analysis of the radial deformation of the high-pressure turbine blade disk (composed of blades and wheel disks) of the aeroengine considering the effect of fluid-thermal-structural coupling, and the direct simulation and decomposed coordinative extremum response surface method (DCERSM) are compared to illustrate the effectiveness and applicability of the proposed DCMERSM in modeling characteristics and simulation performance. The developed DCMERSM is not only suitable for the dynamic reliability analysis of rotor machinery, but also for the reliability analysis of multi-component structures of complex machinery.

Abstract:At present, configuration management in operational and support stage of our military aircraft mainly depends on user own, which is short of informatization and has low efficiency, also is separated from configuration management in development and delivery stage. In this paper, we research the connotation of configuration management in operational and support stage, then propose a configuration management approach in operational and support stage based on analysis of configuration identification, configuration control, configuration status accounting, configuration audit. The proposed approach is applied to aircraft engineering, which shows high efficiency.

Abstract:The reliability level is one of the most significant indexes to be considered for aircraft’s design process. As an aircraft design institute, it is necessary to grasp and trace its aircraft’s reliability level, which should also meet the authority’s requirement. Thus, the paper here performs a reliability assessment methodology study based on aircraft’s failure information in flight test and service period. By making data-collecting requirements，normalizing data table and specifying failure criterion as well as statistical approach for reliability assessment, a systematic reliability assessment process has been created. Meanwhile, starting from the practical engineering, One-sided confidence lower limit method is used to assess the above data, which would give the final reliability assessment outcome. Based on the above methodology, the failure information collected from one aircraft during its one-year flight test and service period is applied to assess its aircraft-level, system-level and device-level reliability. And the final outcome could meet the engineering requirement well. The assessment methodology based on aircraft’s failure information in flight test and service period proposed achieves a full flow track from failure data acquisition, judgment to reliability assessment for aircraft, which could greatly drive the aircraft’s design refinement and its consistent improvement on reliability level.

Abstract:Electro-hydraulic servo valve is an important part of aircraft brake system, which affects the safety of aircraft landing . In order to solve the problem of frequent failure of a certain type of electro-hydraulic servo valve, a model of electro-hydraulic servo valve of the brake system is established by using the regression analysis method. According to the analysis model and the fault symptom criterion, the recent working data of the electro-hydraulic servo valve are analyzed and the fault symptom is diagnosed. The results show that the method can accurately diagnose the fault symptoms of the electro-hydraulic servo valve.The early fault symptom diagnosis can detect the potential fault of the electro-hydraulic servo valve in advance, reduce the fault rate, improve the safety and reliability of the aircraft brake system significantly, and also help to optimize the maintenance strategy and reduce life cycle maintenance costs of the aircraft.

Abstract:Schedule maintenance task interval is a key index representing the reliability and economy of an aircraft. Since the initial maintenance interval approved in Maintenance Review Board Report (MRBR), obtained by MSG-3 analysis method, is relatively conservative, it is significant to optimize the maintenance interval based on in-service data. This paper studied the work flow of the maintenance interval optimization. First, we give the equation to determine the sample size which must be satisfied to initiate the process. Then, we provide a failure trend fitting method which helps us to decide if it is necessary to do the job. Finally, we illustrate the hypothesis test criteria which tells us whether the new targeted interval should be accepted or rejected. The result shows that the proposed method can be used to determine if the new desired maintenance interval for a specific task can be accepted, which further leads the update of the MRBR.

Abstract:Preventive maintenance is the main measure to restore and maintain the safety and reliability of the aircraft. Its optimization has always been a common concern of aircraft manufacturers and users. This paper researches the international mainstream preventive maintenance task optimization methods and their applicable objects. Based on the S4000P ISMO process which is suitable for equipment, and combined with the characteristics of military aircraft, the original process is personalized adjusted, and the logic process of preventive maintenance task optimization is constructed, which can be used for the optimization analysis of military aircraft preventive maintenance task.

Abstract:The operation status of radar power supply system directly affects the safety and performance of the whole radar equipment. How to realize the health status assessment of radar power supply is a problem to be solved. In this paper, a health assessment model is established to achieve this goal. Firstly, the health feature data of radar power supply under normal state is used to train the self-organizing neural network. Then the distance between the monitoring data and the weight vector of the trained self-organizing neural network is calculated. The distance value is converted into the health degree between (0,1). Finally, the health degree is calculated by using the data of accelerated degradation test, According to the calculation of health degree, the health grade is divided. The results show that the health degree calculated by the proposed method decreases with the aging of power supply, which indicates that the method can be used to evaluate the health status of radar power supply.

Abstract:Military aircrafts show the phenomenon of insufficient diagnostic ability in the outfield, which seriously affects the efficiency of aircraft redeployment. In this paper, based on the practical application requirements of fault diagnosis of military aircraft, the testability design problems of airborne system in the process of design and test are analyzed, and the key links in the process of testability design, such as diagnostic capability design and testability test, are analyzed.Therefore, a complete design system for airborne system test is proposed. Aiming at the whole development and use process of military aircraft, the design objectives are defined, and the design, verification and evaluation methods are provided. The original isolated design work is integrated into a complete design system. At the same time, the improvement suggestions on working methods, professional positioning and system support can effectively promote the integration of testability design into the process of airborne system design, improve the testability level of airborne system, and improve the comprehensive diagnosis ability of aircraft.

Abstract:Poor reliability of engine block is a technical problem in airworthiness certification of aviation piston engine. Taking the engine block of a certain type of engine as the research object, the transient load curve of the engine block is obtained and matched through the model, and it is restrained according to the actual installation. The Goodman method is used to analyze the high cycle fatigue of the engine block, the fatigue safety factor of block is obtained. A design method of separated main bearing cap is put forward to optimize the structure of the lower engine block, and the comparative analysis is carried out under the same load conditions. The analysis results show that the fatigue safety factor of the lower block and engine life are improved, and the reliability index is verified by Weibull mathematical model. The durability test of the optimized engine block shows that the reliability of the engine block is improved, which proves that the design method is feasible, and it can be used for reference to improve the reliability of similar structures.