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0AIRCRAFT ON-BOARD EQUIPMENT CONDITIONS PROGNOSTICS 1Abdurashid Abdukaumov, 2Ruslan Zakirov
1Tashkent State Transport University, 2"My Freighter" Air Company https://doi.org/10.5281/zenodo.10723409
Abstract. This paper proposes the results of the investigation of different methods for aircraft on-board equipment conditions prognostics. The proposed method are based on monitoring of two main processes - estimation of natural aging of aircraft on-board equipment and monitoring ofparameters which indicated degradation processes of the equipment.
Keywords: aircraft, diagnostic, equipment, sensors, prognostic, algorithm.
At present time the methods for the technical condition of on-board equipment and aircraft systems prognostics are becoming increasingly relevant. Such methods are necessary for calculating of risks in the flight safety management system.
Operators are interested in using of prognostic methods for predicting the condition of aircraft on-board equipment, seeking to reduce costs and transition aircraft maintenance according to current conditions [1].
There is an also interest in prognostic methods among developers of on-board equipment, for whom estimates of factors affecting the reliability of on-board equipment are significant. This data can be used in the design and modification of On-board equipment.
Many sensors are installed on a modern aircraft and thousands of parameters are recorded. Aircraft developers are ready to install additional sensors and increase the amount of data recorded by Flight data recorder during flight. There is a problem in the insufficient effectiveness of the analysis of the recorded data carried out to diagnose and prognose the condition of the aircraft's On-board equipment [2].
Currently, there are two main directions to the development of algorithms for prognosing of the technical condition of aircraft on-board equipment.
The first one is based on a detailed analysis of a representative set of parameters based on the experience of operating of the aircraft system and knowledge of the physical processes occurring in it. An example of the successful implementation of this method is the algorithms for predicting the technical condition of aircraft engines. In this case, the developers of prognostic algorithms determine the required sets of observed parameters and the requirements for them [3].
The second direction based on analyzing a large massive of the data in order to find deviations from the usual behavior of the system. In this case, the prognostic algorithms process sets of parameters formed intuitively by the developers of aircraft systems without taking into account such significant characteristics as delay in the receipt of information, accuracy of information and others. However, experience shows the effectiveness of this method.
In our opinion, it is necessary to develop both of these prognostic methods. Our interest is in the field of creating of algorithms for prognose of the conditions of a digital computer by studying in detail the behavior of the system under the influence of external conditions.
Modern systems for aircraft systems monitoring are hierarchical and include built-in test equipment (BITE) of modules, and an on-board automated control system. The control data and controlled parameters are recorded on the on-board flight data recorder for post-flight analysis.
The methods of prognosing of the technical condition of the aircraft is a further development of methods for monitoring the technical condition of the aircraft and can be implemented on the hierarchical structure of the on-board monitoring system.
Prognostic methods for specific classes of electronic components is a the basis for prognose the technical condition of a digital device. This paper does not consider the prediction of failure chains, that is, situations where the failure of one unit leads to a violation of the operating conditions of another and may cause its failure [4].
It is proposed to implement the prognostic of the technical condition of the digital unit on the basis of monitoring two main processes - assessing the natural aging of the unit depending on operating conditions and monitoring parameters reflecting its degradation processes. Based on these data, an integral assessment of the degradation level of the unit is formed and a decision on corrective actions is developed. Figure 1 shows a diagram of the organization of prognosing the technical condition of the unit.
Algorithms for prognostic of the unit conditions can be implemented both on board the aircraft (by Aircraft Conditions monitoring system) and on the ground system based on data recorded in flight. Using of the combined option, when part of the calculations is carried out on board, and the other on the ground also possible.
Figure 1. Diagram of the organization of prognosing the technical condition of the unit
At this stage of development, it seems advisable to assess the external manifestations of unit degradation on board the aircraft, and to implement an assessment of the natural aging process of the unit depending on the operating conditions, in a ground-based system.
The aging process of digital units is significantly influenced by their operating conditions. The experience of operating on-board flight information monitoring and registration systems shows that the following parameters characterizing the operating conditions are the most significant for the digital units life limit:
- temperature;
- power supply indicators (voltage, amperage);
- humidity;
- concentration of harmful impurities in the air (salt, dust, etc.);
- vibration level.
In a promising system for the unit technical condition prognostics, it is proposed to use data from the built-in processor temperature sensor to monitor the temperature during operation of the digital unit. This feature is implemented in modern processors. It is necessary to organize the thermal protection of the processor in case of overheating. The processor is the "hottest" part of the unit. The assessment of the impact of operating conditions on the natural aging process of the unit can be carried out both by expert assessment and using a quantitative assessment system.
For expert evaluation, it is proposed to visualize the parameters recorded in flight, reflecting the operating conditions of the aircraft in tabular and graphical form. This function can be implemented in the standard flight information processing program of the ground-based flight information acquisition and processing system. It involves displaying the following information on the computer screen for the selected system:
- average time to failure of the unit (system) - developer data;
- real-time operation of the unit;
- unit lifetime;
- graph (table) of the distribution density of the selected parameter from among the characterizing operating conditions
- the nominal value of the parameter used by the developer to calculate the average time to failure of the unit (shown on the graph of the distribution density of the selected parameter).
This data will help the expert to make a decision about the availability of the resource of the analyzed unit.
To quantify the natural aging of a digital unit, it is proposed to use unit controllability models that allow determining the probability of unit failure depending on the average time between failure of its components (Mean Time Between Failure - MTBF). To calculate the MTBF, depending on the operating conditions, its operating time and life, well-known methods for calculating reliability indicators of electronic means are used.
The proposed method for predicting the technical condition of electronic (digital) equipment, based on monitoring two main processes - assessing the natural aging of equipment depending on operating conditions and monitoring parameters reflecting the degradation processes of equipment.
A list of diagnostic parameters characterizing the operating conditions of the unit, affecting its resource, and external manifestations of degradation processes in it is given. Some of these parameters are registered in modern systems. Obtaining data about others is possible without hardware upgrade of the units. To measure a small part of the parameters, special sensors and communication lines are needed to transmit their data.
Methods of processing diagnostic parameters in the interests of prognosing the residual life of the digital control unit are proposed.
The method is tested using the example of a ground-based flight information control and registration system. At the same time, the system units are the object of research and a tool for testing the technology.
A phased implementation of prognose methods is proposed. At the first stage, visualization of representative parameters with indication of deviations from the norm, and then the introduction of methods for automated processing of these data.
The implementation of the described method will make it possible to make a significant step towards the operation of aircraft according to the condition, provides a mathematical
apparatus for calculating risks in the flight safety management system and will ensure the design
of an aircraft with feedback
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