Extending the Aircraft Availability Model to a Constrained Depot Environment Using Activity-Based Costing and the Theory of Constraints

The Aircraft Availability Model (AAM) assists managers in the selection of an optimal list of items to repair in order to attain the best aircraft availability rate. The model considers procurement or repair costs for the components as if the costs were unit variable as a price, instead of a repair cost representing a mix of both fixed and variable cost. This research used the AAM in conjunction with Activity Based-Costing (ABC) and The Theory of Constraints (TOC) methodologies to investigate the relationships between price, product mix, Aircraft Availability (AA) and total cost. This approach explicitly recognizes that the Air Force Material Command uses its own resources in repairing components, and that it is always operating in a constrained environment in which resources practical capacities are exceeded by requirements that limit the attainable AA. The results of this investigation shows that the choice of the optimal mix of reparable items is sensitive to the pricing method used as well as environmental factors like repair cycle time, fleet size, and the intensity and balanced of shop resource load. In addition, the research found that the performance of the repair center should be evaluated under the metric Aircraft Availability per System Total Cost, following the rationale under the TOC methodology that considers labor costs as operational expenses, fixed in the period, and only raw materials as variable costs

DECISION SUPPORT MODEL IN FAILURE-BASED COMPUTERIZED MAINTENANCE MANAGEMENT SYSTEM FOR SMALL AND MEDIUM INDUSTRIES

Maintenance decision support system is crucial to ensure maintainability and reliability of equipments in production lines. This thesis investigates a few decision support models to aid maintenance management activities in small and medium industries. In order to improve the reliability of resources in production lines, this study introduces a conceptual framework to be used in failure-based maintenance. Maintenance strategies are identified using the Decision-Making Grid model, based on two important factors, including the machines’ downtimes and their frequency of failures. The machines are categorized into three downtime criterions and frequency of failures, which are high, medium and low. This research derived a formula based on maintenance cost, to re-position the machines prior to Decision-Making Grid analysis. Subsequently, the formula on clustering analysis in the Decision-Making Grid model is improved to solve multiple-criteria problem. This research work also introduced a formula to estimate contractor’s response and repair time. The estimates are used as input parameters in the Analytical Hierarchy Process model. The decisions were synthesized using models based on the contractors’ technical skills such as experience in maintenance, skill to diagnose machines and ability to take prompt action during troubleshooting activities. Another important criteria considered in the Analytical Hierarchy Process is the business principles of the contractors, which includes the maintenance quality, tools, equipments and enthusiasm in problem-solving. The raw data collected through observation, interviews and surveys in the case studies to understand some risk factors in small and medium food processing industries. The risk factors are analysed with the Ishikawa Fishbone diagram to reveal delay time in machinery maintenance. The experimental studies are conducted using maintenance records in food processing industries. The Decision Making Grid model can detect the top ten worst production machines on the production lines. The Analytical Hierarchy Process model is used to rank the contractors and their best maintenance practice. This research recommends displaying the results on the production’s indicator boards and implements the strategies on the production shop floor. The proposed models can be used by decision makers to identify maintenance strategies and enhance competitiveness among contractors in failure-based maintenance. The models can be programmed as decision support sub-procedures in computerized maintenance management systems

Investigation of an Avionics Part Deficiencies in Royal Saudi Air Force Fleets

The Royal Saudi Air Force (RSAF) is experiencing a shortage in certain avionics parts due to a lack of reliability. This issue is causing a supply chain disturbance in the F1-15 fleet and the Hawk fleet. One of the factors behind this problem is the environmental effects in Saudi Arabia .The study will investigate and analyze the methods for the Improvement Cycle Processes and the Quality Management within the RSAF repair cycle. Finding show that, the discrepancies are rising during summer and fall time due to the environment change, Other finding were addressed in the study

To repair or not to repair: an investigation of the factors influencing prosumer repair propensity

The Circular Economy is a sustainable system of production and consumption that aims to minimise waste, emissions and energy leakages through a closed system. Repair is one of the strategies to facilitate the transition towards the Circular Economy (CE). Repair is also a behaviour that the prosumer can adopt and enact in collaboration with other citizens in society. The inclination to repair, called explicitly in this thesis, ‘the prosumer’s propensity to repair’ is influenced and affected by a myriad of complex and inter-related elements. Those elements need to be further investigated to support the actors involved in the transition towards the CE to develop interventions to support the prosumer to repair further. The investigation was set in an extreme case scenario by choosing to engage with individuals who, by their affiliation with pro-environmental organisations, appear to be more inclined to engage with pro-environmental behaviours. The investigation focuses on them trying to repair small electrical items because there have been conflicting results in previous research, on the extent to which environmental concerns influence Prosumer Repair Propensity. The literature explores Repair as an activitiy to be embraced by prosumers and strategy to facilitate the transition towards a CE. The review discusses the role, and capacity of the prosumers in to both produce and consume value to support the transition. The literature explores the role of Design in developing solutions to extend product lifespan and to influence prosumer behaviour. The literature in the field of Design for Sustainable Behaviour emphasises the significance of investigating prosumer behaviour before developing interventions. As a result, the literature reviews past research on the factors influencing Prosumer Repair Propensity and behavioural frameworks that could support the investigation. The Theory of Trying and the Transtheoretical model of Change are selected as tools for understanding prosumer repair behaviour as a multi-dimensional object.Two studies are undertaken to meet the research objectives set out for the investigation. Two hundred and eight respondents completed a survey for the Survey study. For the Prosumer study, 10 participants completed a survey, a semi-structured interview and two video-elicitation exercises. The analysis and integration of the findings from the Survey study and Prosumer study helped to consolidate five sets of findings. The first set of findings presents the range of factors influencing Prosumer Repair Propensity; it includes the most significant factors to support the engagement with repair practice and the most critical factors to successfully repair an item. The second set of findings examines the attitudes towards trying to repair. The third set of findings presents the processes of change affecting the prosumer to repair. The fourth and fifth set of findings presents the repair process and considers how the factors and attitudes influence the prosumer at different stages of the repair process. From the findings, suggestions are given on the prosumer actions that can be adopted to support the transition towards the CE. The thesis finally closes on the limitations of the research project and recommends areas for further research to support the prosumer to change.</div

REVERTIA A Circular Economy Business Case

This report presents the results of the Revertia case study, selected in the framework of the R2PI project, among 17 other cases, because of its focus on an activity linked to priority areas of the Circular Economy, namely Plastics and Critical Raw Materials. The information contained in the report is based on the methodology designed within the framework of the R2PI project to understand the characteristics of the business model, evaluate its outcomes and identify the main barriers and enablers of the CEBM. Revertia is an authorised Waste Electrical and Electronic Equipment (WEEE) manager that combines e-waste management services with a circular value proposal consisting in the preparation of IT equipment for reuse. The company responsibly manages an e-waste flow and, by applying secure reconditioning processes, is able to extend the service life of IT equipment that has been discarded. Refurbished equipment, with a 1-year warranty, are sold in second-hand markets or donated. The activity of preparation for reuse also involves the utilization, to the extent possible, of used and recycled components. In addition, the business model is based on efficient logistics, avoiding e-waste transportation when reconditioning is not an option. The value proposition is based on the provision of high added value services to corporate IT equipment users, who need to manage their WEEE responsibly. The value network is thus formed by the origin-customer that generates e-waste and the EEE manufacturers represented through collective schemes. Downstream there are the destination-customers of second-hand and donated products, as well as the WEEE recycling companies to which Revertia's own waste is destined. Revertia's business model is clearly influenced at the context level by the WEEE Directive 2012/19/EU and the Spanish RD 110/2015, which regulate the industry and set targets for reuse and recycling of WEEE. In addition, the market context given by the rapid technological change in the EEE sector, the collective schemes derived from the implementation of the EPR obligation, the maturity of the WEEE recycling industry, the existence of illegal scrap metal agents, and some socio-cultural aspects such as the lack of awareness of WEEE's environmental costs are factors that strongly affect Revertia's activity. The report also presents an assessment of the circularity of the business model. The model corresponds to the Re-make pattern among the CEBM defined in the R2PI project. Its circularity lies in extending the useful life of a product, also integrating used and recycled components as far as possible. Current circularity is limited, since it is not based on services added to this second-hand product, nor is the organisation further able to act on the products manufacture or end of life. Therefore, Revertia takes opportunity of a gap left by other players in the sector (EEE manufacturers). Therefore the business model is dependent on the generation of an e-waste flow as well as on sales of refurbished computers. With regards to the outcomes assessment, the main advantages of the business model are found in the non-financial aspects: reuse of IT equipment for the same use demonstrates clear environmental benefits compared to recycling. In addition, it also allows for greater local employment generation linked to the management and preparation for reuse activity. In the socio-economic area, second-hand products provide access to quality equipment at very affordable prices. The SWOT analysis shows that the main strengths are the long-lasting and stable relationships with the origin-customers, the know-how and expertise of Revertia. The weaknesses point to its dependence on the linear model, therefore, to being able to capture waste streams, in competition with the mature recycling industry. The opportunities lie in the Spanish regulatory framework, which sets targets for the reuse of WEEE, as well as a state of opinion more favourable to responsible and sustainable consumption; however, there are also clear threats to the model, such as the possible entry of more competitors and the lack of sensitivity of EEE manufacturers towards reuse. Based on the analysis, it is concluded that the Re-make CEBM is replicable and transferable, especially as long as the linear economic paradigm is dominant. However, there are a number of business and policy recommendations that may support greater circularity: first, specific agreements with EEE manufacturers to extend circularity from the conception of EEE products until its final disposal after multiple lifetimes; second, at the policy level, tighter regulation, with inspection and sanction systems, incentives for eco-design and product life extension activities, transparent information and monitoring systems, as well as education and training measures are neededThis project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 73037