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To reduce the flammability exposure assessment time and meet the requirements of airworthiness regulations of transport aircraft, inerting system has become the standard configuration of modern civil aircraft. Therefore, airworthiness regulations put forward definite quantitative index requirements for the safety of inerting system, and to obtain the quantitative data of the safety of inerting system, it is necessary to solve the calculation method. As one of the quantitative/qualitative evaluation techniques for system safety, fault tree analysis is recognized by international airworthiness organizations and national airworthiness certification agencies. When fault tree analysis technology is applied to quantitative analysis of the safety of inerted system, there are still some problems, such as heavy margin of constructing fault tree, great difficulty, high requirement for analysts and poor accuracy of solving when there are too many minimum cut sets. However, based on tens of thousands of flight simulation tests, Monte Carlo random number generation method can solve this problem.

In this paper, the fault tree of airborne inerting system is established, and the top event is airborne inerting system losing air separation function. Monte Carlo method based on random number generation is used to carry out system security analysis. The reliability of this method is verified.

The static fault tree analysis method based on Monte Carlo random number generation can not only solve the problem of quantitative analysis of inerting system, but can also avoid the defects of complicated solution and inaccurate solution caused by the large number of minimum cut sets, and its calculation results have good reliability.

The research results of this paper can be used as supporting evidence for airworthiness compliance of airborne inerting system.

The research results of this paper can provide practical guidance for the current civil airworthiness certification work.

To ensure the safety of aircraft fuel tanks, the FAA issued an airworthiness clause (25.981(b)) suggesting that the risk of combustion and explosion be reduced by installing a Flammability Reduction Means or an Ignition Mitigation Means. The airflow distribution method has a significant effect on the inerting performance. Therefore, this study aims to determine an optimum airflow distribution method of the inerting system.

This paper establishes the calculation model of the oxygen concentration in the ullage of a multi-bay fuel tank, calculates the oxygen concentration in the ullage of an aircraft tank in single-flow and dual-flow modes under series and parallel ventilation methods and analyses the inerting performance of the tank under different airflow distribution methods.

The results show that: (1) the bleed flow rate required to achieve whole process inerting of multi-bay fuel tank in dual-flow mode is lower than that in single-flow mode; (2) under the parallel ventilation method, the decrease of oxygen concentration and the uniformity of each bay are better than that in the series ventilation method; (3) dual-flow mode staged ventilation method can be used to achieve the whole process inerting of the tanks under the minimum engine bleed consumption.

The novelty of this paper is to analyze and optimize the airflow distribution method of the inerting system under the whole flight envelope to minimize the engine bleed consumption.

This paper aims to improve the previous fuel scrubbing model and find out the relationship between bubble diameter and scrubbing efficiency (ƞ).

A fuel tank scrubbing test bench was established to verify the accuracy of this model. Ullage and dissolved oxygen concentration were measured, and images of bubble size and distribution were collected and analyzed using image analysis software.

The bubble diameter has a great influence on ullage and dissolved oxygen concentration during the fuel scrubbing process. The scrubbing efficiency (ƞ) has an exponential relationship with bubble diameter and decreases rapidly as the bubble diameter increases.

The variation of the ullage and dissolved oxygen concentration predicted by this model is more accurate than that of the previous model. In addition, the study of bubble size can provide a guidance for the design of fuel scrubber.

This study not only improves the previous fuel scrubbing model but also develops a method to calculate scrubbing efficiency (ƞ) based on bubble diameter. In addition, a series of tests and analyses were conducted, including numerical calculation, experiment and image analysis.

The study aims to reveal regularities of collective decision in groups of varying cooperativity and to investigate the influence of individualism–collectivism cultural dimension on the emergence of collective behavioral entities.

An agent-based model of group behavior is used to simulate the logic of collective binary decisions defined by reaching a consensus threshold. The key parameter of the model is the cooperativity of interaction between individuals which locates the group in individualism–collectivism cultural dimension. The probabilities of collective decisions are measured as a function of individual preferences and the strength of cooperation between agents.

Strong, weak and middle point cooperativities of inter-individual interaction define three distinct regimes of collective decision logic, namely, individualism, conformism and criticality. The critical organization allows the group to generate coherent non-predetermined collective behavior in statistical agreement with individual preferences.

Emergent collective behavior with coherent and nondeterministic decision-making can be modeled in an agent-based approach with local interaction between individuals tuned to a critical point. Variation of a single cooperativity parameter accounts for a continuous transition between organizations of the group inherent to inert matter and living systems.

A new organization of social systems distinguished by internally relaxed relations and large-scale freedom is found beyond the traditional individualism–collectivism contraposition. This state is reached by tuning behavioral logic of individuals to a critical balance of individual and collective values.

Individualist, conformist and critical regimes of collective organization distinct in terms of integrity, complexity and determinism are recognized as universal organizational classes of nature spanning both inert and living systems. In particular, individualist and conformist regimes produce simple deterministic behavior typical for gases and solid bodies, whereas the critical organization generates complex nondeterministic behavior inherent to living organisms.

Operations strategy/global operations/value chain.

BA/Master level – The case can be applied to support operations strategy discussions related to the link between context, configuration, and capabilities, and particularly to discuss internationalization strategy and global operations.

The case is initiated with an overview of the wider corporate and industrial context, which are included to supply contextual information pertinent to the understanding of competitive requirements and strategic choices of the company. The case then moves into establishing an understanding of the operationalization of these requirements and choices through a discussion of the structural configuration and organizational capabilities.

The case it expected to build an understanding of the fit between competitive priorities and their operationalization within structural and infrastructural decision areas.

Teaching note.

The number of passengers in the aviation sector following COVID-19 has recovered in 2023 and is 5% higher than it was in 2019. The average annual growth of air travel is predicted to be 3.2% between 2019 and 2039. This means the need for aircraft maintenance, repair and overhaul (MRO) services will also increase. Moreover, the stakeholders require lower costs, higher effectiveness/market share and sustainability. These expectations can be realized only with the identification, development and implementation of new innovations while improving and optimizing the already used processes and procedures. Since only highly qualified graduates can reach these requirements, the need for profession-specific MSc and PhD level engineers has elevated significantly. The purpose of this paper is to introduce the development and implementation of a new MRO higher educational framework program in strong cooperation with enterprises and universities.

The emphasis is placed on the program’s scouting, investigation, development, realization and evaluation by defining key performance indexes and aiming for the optimal solution for all participants.

The result of this study is the establishment of a new educational framework, the reinvention of the MSc curriculum and the integration of PhD-level researchers in the industry in a way that fulfills the needs and requirements of the MRO sector. In return, it will give various benefits to all parties involved.

The novelty of this work comes from creating a new educational MSc and PhD level framework that can push the MRO industry forward and fill the gap of missing engineers in this field. Plus, the newly developed program is highly flexible and can be used by other players in the economy after making some adaptions and modifications.

This study aims to seek a new economic and environmental protection fuel tank inerting method.

The principle that serves as the basis for the cooling inerting process is described, the workflow of the cooling inerting system is designed, the mathematical model of the cooling inerting system is established, and the important performance changes of cooling inerting in the flight package line and the influence of key parameters on it are simulated by using Modelica software.

The results show that the cooling inerting system can be turned on to quickly reduce the vapour concentration in the gas phase in the fuel space and reduce the temperature below the flammability limit. Within a certain range of pumping flow, the inerting effect is more obvious when the pumping flow is larger. Simply running the cooling inerting system on the ground can remain the tank in an inert state throughout the flight envelope.

However, cooling inerting is suitable for models with fewer internal heat sources. An excessive number of internal heat sources will lead to inerting failure.

This study provides theoretical support for the feasibility of cooling inerting. Cooling inerting does not require engine air, and the cooling is mainly accomplished with air, which places a small load on the cooling system and has a much lower cost than the airborne hollow fibre film inerting technology widely used at present. It is a promising new inerting technology.

Determining the variation law of the oxygen concentration in the ullage space of the fuel tank is the key to the design of the inert system. Among various factors affecting the oxygen concentration in the ullage space of the fuel tank, the temperature difference between day and night shows particular importance while relevant analysis and calculation are scarce.

This study establishes a theoretical simulation model of the central wing fuel tank of an aircraft according to the relevant provisions of day-night temperature variation in FAR25 airworthiness regulations, verifies the model with the existing experimental data and discusses the corresponding relationship between the oxygen concentration in the ullage space of the fuel tank and the day-night temperature difference. The influence of day and night temperature difference, fuel type, fuel load rate, initial oxygen concentration, dissolved oxygen evolution and other factors on the oxygen concentration in the ullage space of the fuel tank were analyzed, and the limit of initial oxygen concentration of the fuel tank before the shutdown at night meeting the requirements of the airworthiness provisions was proposed.

The results show that the temperature difference between day and night, fuel load rate, initial oxygen concentration and other factors have different effects on the oxygen concentration in the ullage space of fuel tank. The initial oxygen concentration limit before shutdown shall be 2% below the 12% oxygen concentration stipulated by FAA.

The research results in this paper will be of good reference value to the design of the inert system and the calculation of the flammability exposure evaluation time. This paper aims to be good reference of the design of the inert system and the calculation of the flammability exposure evaluation time.

The research results of this paper can provide practical guidance for the current civil airworthiness certification work.

This study aims to get the essential data of the solubility and diffusion coefficient of gas in jet fuel for appropriately designing a kind of on-board inert gas generation system.

A test apparatus based on pressure–decay method was constructed to measure solubility and diffusion coefficient of gas in liquid. The test apparatus and method were verified via measurement of solubility and diffusion of CO₂ in the pure water.

The solubility of CO₂ and O₂ in RP-3 jet fuel with the temperature from 253 to 313 K under three various pressures were measured and compared with theoretical value calculated by a relative density method provided in the standard of ASTM D2780-92, and the deviation is within 10 per cent. The diffusion coefficients of CO₂ and O₂ in RP-3 jet fuel are determined by monitoring the gas pressure in a hermetic cell versus time with the temperature from 253 to 333 K. The measured diffusivity-temperature relation can be well fitted through the Arrhenius equation for engineering applications. The obtained correlation can be used to predict the diffusion coefficient of CO₂ and O₂ in RP-3 jet fuel under a wide temperature range.

The semi-empirical correlation of solubility and diffusion coefficient in RP-3 jet fuel obtained from the experimental data could be used to support the design of an inert gas generation system.

There are no essential data of solubility and diffusion of CO₂ and O₂ in RP-3 jet fuel; therefore, it is fatal if the quantity and rate of mass transfer of CO₂ and O₂ in RP-3 jet fuel must be assessed, e.g. during the design of green on-board inert gas generation system.

The EcowavePlus is a high performance wavesoldering system designed by Electrovert to optimise the no‐clean soldering process and to be environmentally friendly. The ‘green’ machine is configured to take advantage of the new volatile organic compound (VOC) free flux chemistries and the latest flux application techniques. Patented forced convection preheating is employed to ensure complete drying of water based fluxes. The coN2tour selective inerting system for the solder waves provides all the process benefits of inert soldering at an extremely low nitrogen consumption rate. All exhaust emissions in the machine are captured and treated before being released into the environment.