An analytical method for predicting life-cycle maintainability labor costs is developed. The purpose of the analytical method is to allow the evaluation of products, based on life-cycle labor cost, early in the design process. The Boeing 737-300/400/500 Bleed Air Control System is used as a test model, and the results of the analysis are compared with historical data from this system. Four prospective design changes to the Bleed Air Control System are analyzed to demonstrate the ability of the analytical method to compare different designs or design changes. / Graduation date: 1997

Due to a progressive market shift to a customer-driven environment, the influence of engineering changes on the product's market success is becoming more prominent. This situation affects many long lead-time product industries including aircraft manufacturing. Derivative development has been the key strategy for many aircraft manufacturers to survive the competitive market and this trend is expected to continue in the future. Within this environment of design adaptation and variation, the main market advantages are often gained by the fastest aircraft manufacturers to develop and produce their range of market offerings without any costly mistakes. This realization creates an emphasis on the efficiency of the redesign process, particularly on the handling of engineering changes. However, most activities involved in the redesign process are supported either inefficiently or not at all by the current design methods and tools, primarily because they have been mostly developed to improve original product development. In view of this, the main goal of this research is to propose an aircraft redesign methodology that will act as a decision-making aid for aircraft designers in the change implementation planning of derivative developments. The proposed method, known as Strategic Planning of Engineering Changes (SPEC), combines the key elements of the product redesign planning and change management processes. Its application is aimed at reducing the redesign risks of derivative aircraft development, improving the detection of possible change effects propagation, increasing the efficiency of the change implementation planning and also reducing the costs and the time delays due to the redesign process. To address these challenges, four research areas have been identified: baseline assessment, change propagation prediction, change impact analysis and change implementation planning. Based on the established requirements for the redesign planning process, several methods and tools that are identified within these research areas have been abstracted and adapted into the proposed SPEC method to meet the research goals. The proposed SPEC method is shown to be promising in improving the overall efficiency of the derivative aircraft planning process through two notional aircraft system redesign case studies that are presented in this study.

A indústria aeronáutica está constantemente à procura de materiais que ofereçam benefícios em termos de redução de peso, desempenho e custo. Corrosão e fadiga em ligas de alumínio são questões importantes na avaliação da vida útil em estruturas de aeronaves e na gestão de frotas. O objetivo deste trabalho foi avaliar os processos de corrosão e corrosão-fadiga nas ligas 2198-T851 e 7081-T73511, que são promissoras substitutas das ligas 2524-T3 e 7050-T7451 normalmente utilizada pela indústria aeronáutica. As técnicas de potencial de circuito aberto (PCA), polarização potenciodinâmica, polarização potenciodinâmica em eletrodo cilíndrico rotatório, espectroscopia de impedância eletroquímica (EIE), eletrodo vibratório de alta resolução (SVET) e mapeamento de potencial (SKP) foram utilizadas para esclarecer e quantificar os mecanismos de corrosão destas ligas de alumínio. Os ensaios de fadiga e corrosão-fadiga foram realizados com uma razão de carga (R) de 0,1 e frequência de 15 Hz em ar e 0,1 Hz em meio de névoa salina. As amostras, antes e após os testes de corrosão e corrosão-fadiga foram analisadas usando microscopia eletrônica de varredura (MEV). As características localizadas das quatro ligas estão essencialmente relacionadas com a existência de compostos intermetálicos que, devido à sua natureza diferente, podem ser catódicos ou anódicos em relação à matriz de alumínio. Os resultados de corrosão-fadiga mostraram uma ligeira redução no limite de fadiga para as ligas da série 2XXX e 7XXX. Essa redução pode ser atribuída à formação de cavidades de corrosão (pites). Considerando o estágio de propagação de trinca, o ambiente salino aumentou a taxa de crescimento de trinca para um mesmo intervalo de fator de intensidade de tensão. / The aircraft industry is constantly looking for improved materials which offer benefits in terms of performance, weight and cost savings. Corrosion and fatigue of aluminium alloys are major issues in the service life assessment of aircraft structures and in the management of aging air fleets. The aim of this study was to evaluate the corrosion and corrosion fatigue processes of 2198-T851 and 7081-T73511 aluminium alloys, which are promising substitutes for the base line 2524-T3 and 7050-T7451 aluminium alloys normally used in aircraft fabrication. Open circuit potential monitoring (OCP), potentiodynamic polarization, potentiodynamic polarization in rotating cylindrical electrode, eletrochemical impedance spectroscopy (EIS), Scanning vibrating electrode technique (SVET) and Scanning Kelvin Probe (SKP) techniques have been used to clarify and quantify the corrosion mechanisms of these Al alloys. Fatigue and corrosion fatigue tests were carried out an applied stress ratio (R) of 0.1, 15 Hz frequency for air and 0.1 Hz frequency for salt spray using a sinusoidal wave form in all cases. The specimens, before and after corrosion and corrosion-fatigue testing were analyzed using scanning electron microscope (SEM). The localised features of all the four alloys are essentially related to the existence of intermetallics that, due to their different nature, may be cathodic or anodic sites in relation to the Al matrix. SEM and EDS analysis allowed to identify the intermetallics that are more active in determining the corrosion behavior of the specimens. The fatigue corrosion results show a slightly reduction in the fatigue life limit by chloride environment for the 2XXX and 7XXX aluminium alloys in each aged condition might be partially attributed to the formation of corrosion pits. Considering the crack propagation stage, the saline environment increased the fatigue crack growth rate for the same range of stress intensity factor.

In the past two decades policy assisting computer models have made a tremendous impact in the analysis of national security issues and the analysis of problems in various government affairs. SURMAN (Survivability Management) is a policy assisting model that has been developed for use in national security planning. It is a large scale model formulated using the system dynamics approach of treating a problem in its entirety rather than in parts. In this thesis, an encapsulation of SURMAN is attempted so as to sharpen and focus its ability to perform policy/design evaluation. It is also aimed to make SURMAN more accessible to potential users and to provide a simple tool to the decision makers without having to resort to the mainframe computers. To achieve these objectives a personal/microcomputer version of SURMAN (PC SURMAN) and a series of curves relating inputs to outputs are developed. PC SURMAN reduces the complexity of SURMAN by dealing with generic aircraft. It details the essential survivability management parameters and their causal relationships through the life-cycle of aircraft systems. The model strives to link the decision parameters (inputs) to the measures of effectiveness (outputs). The principal decision variables identified are survivability, availability, and inventory of the aircraft system. The measures of effectiveness identified are the Increase Payload Delivered to Target Per Loss (ITDPL), Cost Elasticity of Targets Destroyed Per Loss (CETDPL), Combat Value Ratio (COMVR), Kill to Loss Ratio (KLR), and Decreased Program Life-Cycle Cost (DPLCC). The model provides an opportunity for trading off decision parameters. The trading off of survivability enhancement techniques and the defense budget allocation parameters for selecting those techniques/parameters with higher benefits and lower penalties are discussed. The information relating inputs to outputs for the tradeoff analysis is presented graphically using curves derived from experimentally designed computer runs. / M.S.

Damages of metallic aircraft structures that occur during manufacturing, assembly and in service require local repair. Especially with current service-life extensions of ageing aircraft fleets, the importance of such repair methods is increasing. Typically, the repair of smaller damages on aluminium fuselage or wing skins is done by riveting a patch onto the flawed structure. However, the use of rivets reduces the strength of the structure and promotes fatigue. Joining the patch by adhesive bonding would not only offer more homogenous load distribution and weight savings, but even an increase of structural integrity. Metal adhesive bonding is commonly used in aeronautics, but requires elaborated surface treatments of the adherends, employing hazardous chemicals like chromates, due to the high durability demands. Furthermore, these treatments are usually tank processes that are not suitable for local repairs. Hence, there is a strong need for locally applicable surface preparation methods that allow safe and reliable adhesive bonding of primary aircraft structures. The aim of this thesis is to assess the – still emerging – method of atmospheric pressure plasma deposition of silicon (Si) containing compounds concerning its suitability as surface preparation for adhesive bonding of aluminium aerostructures. Atmospheric plasma deposition is not yet used in the aircraft industry, and the knowledge on functionality of this technology concerning bonding of aluminium parts is limited. Moreover, the durability requirements of the aircraft industry greatly exceed the standards in other industries. Hence, special attention is paid to a thorough analysis of the key characteristics of the deposited coupling films and their effectiveness in terms of adhesion promotion as well as joint durability under particularly hostile conditions. In order to do so, the altering mechanisms of the treated joints and the behaviour of the coupling films during accelerated ageing will be investigated in detail for the first time in this thesis. Furthermore, the influence of the aluminium surface pre-treatment (i.e. topography and oxide properties of the substrate) on the overall joint performance after coupling film deposition is thoroughly examined. Based on these findings, the surface preparation is optimised, and a process is developed to achieve maximal joint performance. As alternative local surface treatments prior to adhesive bonding, solution derived deposition of silane and sol-gel films have already been widely investigated and can be considered as reference, even though these techniques are rarely used in civil aeronautics. The knowledge on their effectiveness and capabilities in corrosive atmosphere is still very limited. Therefore, all analyses of degradation mechanisms are conducted for both plasma deposition and wet-chemical reference treatments to reveal the differences and communalities of the two Si-based coupling films. Physical and chemical analysis of the films, the oxides and the interfaces reveal differing, but interdependent failure mechanisms that are inhibited differently by the individual coupling films. Using the optimum deposition parameters, plasma films of only several nanometres in thickness significantly enlarge the corrosion resistance of bonded joints, reaching almost the level of anodising treatments with several micrometres thick oxides and strongly outperforming solution derived silane treatments. However, plasma film performance is found to be largely dependent on the precursor selection. With plasma deposition of 3-glycidoxypropyltrimethoxysilane, which has not been reported before, highest joint stability is achieved. Moreover, it is discovered that the properties of plasma and solution derived silane based films are complementary. It is shown that an optimised combined plasma and wet-chemical treatment process provides even superior resistance to bondline corrosion than state-of-the-art anodising techniques.

Thesis (MBA (Business Management))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: Safety culture is of paramount importance in high risk industries such as railway maintenance, nuclear, offshore industries and aviation industry, resulting in the assessment of safety culture in these industries. The purpose of this study is to assess the safety culture amongst maintenance engineers at a leading airline in South Africa. The approach to the study was twofold. Firstly, an intensive literature study was conducted, followed by an empirical study. The literature study clarified and zoned in on the importance safety management system and the pivotal role of human factors in aviation maintenance and its contribution to safety culture. The Airways Technical Safety Culture Survey (ATSCS) was distributed to all the maintenance engineers employed at a major South African airline. The subsequent data, received from 113 respondents, was interpreted and then analysed using the SPSS statistical software package. Firstly, the responses to the seven scales of the ATSCS were examined to determine whether the data was suitable for factor analysis. The data was analysed using the SPSS statistical package. A principal axis factor analysis, with a Varimax rotation was performed on the data in order to determine which factors cluster together. Scale reliability was determined by making use of Chronbach’s coefficient alpha. The average mean of the corrected correlations between each scale item was also calculated to examine the internal homogeneity and unidimensionality of the different scales. Next, the items were subjected to item analysis. The mean, standard deviation, skewness and kurtosis were calculated for the sample scores of the ATSCS. The influence and effect of the biographical variables on the maintenance engineers’ attitudes towards safety were determined by comparing the responses of various employee subsets with one another by means of t-tests and ANOVA. The results of the t-tests revealed that ethnicity had a statistically significant effect on the safety attitude with regard to management’s attitude towards safety and safety training. The effect sizes were calculated to determine the strength of the relationship, and this was found to be of medium effect. The ANOVA results indicated that education, geographical location and fleet qualification have no effect on the safety attitude of the population. However, an ANOVA of work area revealed that the major maintenance work area differs significantly from the other two groups in five areas of the Safety Culture Survey. Finally, the overall responses of the majority of participants in this study were very positive with regard to the seven core factors related to attitudes toward safety. It is suggested that future studies of this nature should incorporate a larger sample consisting of cross-cultural carriers in the global industry. This will confirm the external validity of the present study and support the transfer of findings to other maintenance engineers. / AFRIKAANSE OPSOMMING: Talle studies is onderneem om die veiligheidskultuur in hoë-risiko industrieë soos die spoorweginstandhoudingsbedryf, kernbedryf en olieboorbedryf te definieer en te assesseer terwyl daar slegs ’n paar gedokumenteerde pogings in die lugvaartbedryf bestaan. Die doel van hierdie studie is om die veiligheidskultuur by instandhoudingsingenieurs in een van die vernaamste lugrederye in Suid-Afrika te assesseer. ’n Literatuurstudie en ’n empiriese studie is uitgevoer. Die literatuurstudie is gerig op die aspekte van veiligheidsbestuur en die rol van menslike faktore in lugvaartinstandhouding en die bydrae daarvan tot ’n veiligheidskultuur. Die Lugvaart Tegniese Veiligheidskultuuropname (ATSCS – Airways Technical Safety Culture Survey) is aan al die instandhoudingsingenieurs by ’n groot Suid-Afrikaanse lugredery versprei. Die data wat van 113 respondente ontvang is, is geïnterpreteer en toe ontleed met behulp van die SPSS statistiese sagtewarepakket. Eerstens is die response op die sewe skale van die ATSCS ondersoek om te bepaal of die data vir faktorontleding geskik is. Hoofasfaktorontleding is met behulp van SPSS op die data toegepas, met ’n Varimax-rotasie om vas te stel watter faktore saambondel. Die betroubaarheid van die skale is bepaal deur Chronbach se koëffisiënt alfa te gebruik. Die gemiddelde van gemiddeldes van die gekorrigeerde korrelasies tussen die items van elke skaal is ook bereken om die interne homogeniteit en uni-dimensionaliteit van die verskillende skale te ondersoek. Daarna is die items aan itemontleding onderwerp. Die gemiddelde, standaard afwyking, skeefheid en kurtosis is vir die steekproeftellings van die ATSCS bereken. Die invloed en effek van die biografiese veranderlikes op die instandhoudingsingenieurs se ingesteldheid teenoor veiligheid is bepaal deur die response van verskillende werknemerondergroepe met mekaar te vergelyk met behulp van t-toetse en ANOVA. Die resultate van die t-toetse het aan die lig gebring dat etnisiteit ’n statisties beduidende uitwerking op die veiligheidsingesteldheid het ten opsigte van die bestuur se ingesteldheid teenoor veiligheid en veiligheidsopleiding. Die effek se groottes is bereken om die krag van die verwantskap te bepaal, en daar is bevind dat dit ’n medium effek het. Die ANOVA-resultate dui aan dat opleiding, geografiese ligging en vlootkwalifikasie geen uitwerking op die veiligheidsingesteldheid van die universum het nie. ’n ANOVA van die werkarea het egter aan die lig gebring dat die belangrikste instandhoudingswerkarea beduidend van die ander twee groepe verskil ten opsigte van vyf areas van die Veiligheidskultuuropname (ATSCS). Laastens was die oorkoepelende response van die meerderheid deelnemers aan hierdie studie baie positief ten opsigte van die sewe kernfaktore wat met ingesteldheid teenoor veiligheid verband hou. Daar word voorgestel dat toekomstige ondersoeke van hierdie aard ’n groter steekproef van kruis-kulturele lugrederye in die globale bedryf inkorporeer. Dit sal die eksterne geldigheid van die huidige studie bevestig en die oordrag van bevindinge aan ander instandhoudingsingenieurs ondersteun.

Call number: LD2668 .T4 1986 H44 / Master of Arts / History

The Cape Town Convention and the Aircraft Protocol came into force on 1st March 2006. To date, the Convention has seventy-four States Parties, the Aircraft Protocol sixty-eight States Parties, and together they can be regarded as one of the most successful recent commercial law treaties. The Convention's overriding object is to offer creditors the highest possible protection in the form of an effective, speedy and strong legal remedial framework for the international enforcement of creditors rights in the event of the debtor's default or insolvency. The underlying rationale is that this will lead to significant reductions in borrowings costs for lenders to the advantage of all interested stakeholders in the aircraft sector. However, without effective implementation of the remedial system of the Convention and the Aircraft Protocol, it is difficult for financiers to have confidence that they are able to defend their legal rights effectively. This thesis investigates the structure and contents of the Convention's remedial system in a chronological order, but it does not purport to be a comprehensive and systematic monograph on the Convention's remedies as already done by the Convention's Official Commentary. It consists of four parts each of which investigates a particular core aspect of the implementation and operation of the Convention's remedial system in practice. In particular, it investigates the Convention's declaration system, and its procedural, substantive and insolvency remedies to ensure an effective and comprehensive protection of creditors in aircraft finance. In doing so, it identifies critical lessons for the implementation of the treaty in civil and common law jurisdictions.

S’appuyant sur une approche comparative et historique au niveau de la firme, cette thèse étudie les dynamiques de la réussite économique à long terme de la construction d'avions civils aux Etats-Unis et en Europe. Cette analyse est menée à partir de l’étude d’Airbus et de Boeing qui sont les deux plus grandes firmes du secteur aéronautique au niveau mondial. La thèse identifie les conditions sociales qui influencent les capacités concurrentielles des deux firmes et les pratiques qui jouent un rôle sur l’amélioration ou la dégradation des capacités productives de leur secteur à travers un cadre analytique basé sur les modèles productifs / les modèles d’affaires (productive/business models). Les trois éléments majeurs de l’activité productive au niveau de la firme, à savoir la stratégie d’entreprise, la structure organisationnelle et le degré d’engagement financier sont analysés dans ce cadre appliqué à l’intégration de systèmes. Les résultats de cette recherche montrent qu’il existe une forte corrélation entre la sous-traitance massive, la financiarisation des stratégies d’entreprise et les relations conflictuelles de travail. L’évolution des stratégies d’Airbus et de Boeing et leur influence sur l’amélioration ou la dégradation de leurs capacités productives sont fortement liées aux transformations dans le domaine financier et dans l’organisation productive / les relations industrielles qui caractérisent les économies occidentales depuis les trois dernières décennies. Les conséquences des actions menées par les entreprises sur la promotion de l’emploi dans leur(s) pays d’origine sont questionnées et des implications en termes de stratégies d’entreprise et de politiques publiques sont tirées de cette thèse. / This dissertation analyzes the dynamics of long-term success in commercial aircraft manufacturing in the US and Europe performed through a historical-comparative methodology employed for firm level analysis. The firm-level case studies are Airbus and Boeing, the two biggest firms in the commercial aircraft manufacturing industry. Through an analytical framework concentrated on business/productive models of corporate activity, the study identifies the social conditions that influence the competitive capabilities of these two companies and their practices in upgrading, or downgrading, the productive capabilities of their respective industries. The three main elements of firm-level productive activity under modern capitalism, namely corporate strategy, organizational structure and financial commitment are analyzed through the lens of the systems-integration business/productive model framework. The results of the research show that there is a strong correlation between extensive outsourcing, financialization of business strategies and conflicting employment relations. Distinct constructive and destructive processes of corporate strategies of Airbus and Boeing are strongly linked to the role of the transformations of finance and work organization/industrial relations in the last three decades in Western economies. The consequences of corporate action on the promotion of secure jobs with positive prospects for their respective economies are questioned and relevant implications are drawn for business and government policy.

Ma thèse porte sur les chaines de valeurs globales et le commerce international.Les progrès technologiques et la baisse des coûts de communication ont favorisé la fragmentation des processus de production entre différents pays et secteurs et l’expansion des chaines de valeurs globales. Cette nouvelle organisation entraine des modifications majeures au niveau des flux du commerce international et une interdépendance croissante des économies.L’objectif de cette thèse est donc d’étudier l’impact de l’organisation des chaines de valeur globales sur les problématiques du commerce international, que ce soit à l’échelle macroéconomique (avantages comparatifs des pays) ou microéconomique (performance des entreprises).Il s’agit d’une thèse sur travaux, composée de trois chapitres.Le premier chapitre analyse l’organisation d’une chaine de valeur globale à partir des avantages comparatifs. Je montre ainsi que les avantages comparatifs sont différents lorsqu’ils sont mesurés à l’aide de données commerciales en valeur ajoutée par rapport aux données commerciales traditionnelles. Cette nouvelle mesure des avantages comparatifs implique un schéma de spécialisation sectorielle différent dans une chaine de valeur globale. L’identification des facteurs à l’origine des avantages comparatifs dans ce contexte de fragmentation met en évidence le rôle crucial de la qualité institutionnelle, son effet étant plus important que les facteurs traditionnels tels que le travail ou le capital.Les deux derniers chapitres étudient les chaines de valeur globales à travers l’organisation des entreprises dans le secteur aéronautique en France, dans la région Midi-Pyrénées Aquitaine.Le deuxième chapitre évalue l’impact du recours à la sous-traitance sur les performances des entreprises de l’aéronautique, en se basant sur des données d’enquête de l’Insee de 2006 à 2011. J’étudie plus particulièrement l’impact de la localisation de la sous-traitance et je démontre que les entreprises ayant recours à la sous-traitance domestique et internationale affichent, en moyenne, une productivité plus élevée que celles qui ne sous-traitent pas ou sous-traitent uniquement au niveau domestique. L’utilisation de régressions quantiles montre que l’effet est d’autant plus élevé pour les entreprises les moins productives.Enfin, le dernier chapitre étudie l’impact de la crise financière de 2007-2008 sur les entreprises du secteur de l’aéronautique. Je distingue deux types d’entreprises, celles qui produisent des biens différenciés et celles qui produisent des biens standardisés. Les résultats mettent en évidence la plus forte résilience des entreprises produisant des biens standardisés. Cette meilleure résilience s’explique par une plus grande capacité à diversifier leurs marchés en cas de crise, notamment via l’utilisation de logiciels facilitant la sous-traitance et diminuant les coûts de coordination ainsi que leur statut d’exportateur, qui permet d’accéder plus facilement aux marchés internationaux. / My thesis is about global value chains and international trade.Technological progress and lower communication costs have foster the fragmentation of the process of production across countries and sectors and the expansion of global value chains. This new organization led to major changes in international trade flows and a growing interconnectedness of economies.The objective of this thesis is to study the impact of the organization of global value chains on international trade either at the macroeconomic level (countries’ comparative advantages) or microeconomic (firm performances).This thesis is organized on three chapters. The first chapter assesses the impact of global value chains on the comparative advantages of countries based on value added trade data.In this first chapter, I investigate the organization of global value chains based on comparative advantages. I show that comparative advantages are different when computed using value added trade data compared to gross trade data, which leads to a different sectoral specialization in a global value chain. The identification of the determinants of comparative advantages shows the importance of the quality of institutions, its impact is greater than traditional factors like labor or capital.The two last chapters study global value chains through plants in the aircraft industry in France, in the region Midi-Pyrénées Aquitaine.The second chapter provides empirical evidence of the impact of outsourcing and its origin on plant level performance in the aircraft sector based on panel data from 2006 to 2011. Specifically, I study the impact of the localization of outsourcing and show that, in average, plants that outsource their activities both domestically and internationally exhibit a higher productivity level, compared to plants not outsourcing or outsourcing only domestically. Quantile regressions shows that this effect is higher for lower productive plants.The last chapter describes the impact of the 2007-2008 financial crisis on plants on the aircraft sector in France. I identify two types of plants, generic outsourcers, producing standardized goods, and contractual outsourcers, producing customized goods. I show that generic outsourcers were more resilient during the crisis than contractual ones. Digitization, which reduces coordination costs and exporting activities, which permits to diversify their markets, explain part of the resilience of generic outsourcers to the crisis impact.