Civil aero-propulsion application: effect of thrust rating change on engine time on-wing

Engine fleet management has always been one of the most challenging tasks in any airline as it requires assuring reliability and cost effectiveness of engine operation at all times. The engine maintenance expenses are quite significant and accounts for about one third of the total aircraft maintenance costs. For all airlines with “Labour & Material” type of contractual arrangement with respective OEM / MRO provider, maximizing engine’s Time On-Wing (TOW) is extremely crucial to face lower maintenance costs, while at the same time abiding by governing airworthiness standards. Engine’s TOW is generally limited due to at least one of the following reasons: performance degradation reflected by lower Exhaust Gas Temperature (EGT) margin, hot section hardware life monitored by regular borescope inspections and Life Limited parts (LLP) expiry enforced by OEM or regulatory authority. After introducing relevant aero engine maintenance concepts and terminology, this thesis will serve to provide both qualitative and quantitative assessment of how certain operational factors of flight profile influence engine performance deterioration and maintenance costs. One such factor is the thrust rating of the engine. Higher thrust gives rise to higher internal temperatures, exposing engine hardware to greater mechanical and thermal stresses and therefore leading to faster rate of degradation and earlier engine removal. This thesis will be of interest to airlines having at least two different types of aircraft models in their fleet with different average flight profiles but powered by the same engine model with the required thrust variant. A particular engine may spend some time first on the aircraft that requires higher thrust rating before being switched to the aircraft that requires lower thrust rating or vice versa. This thesis will look into the feasibility of such an operational strategy through different aspects and discuss its effectiveness in retaining the engine performance for a longer time, thereby affecting the operating fuel costs and restoration costs per flying hour expected at the time of shop visit

The BG News April 7, 1989

The BGSU campus student newspaper April 7, 1989. Volume 71 - Issue 115https://scholarworks.bgsu.edu/bg-news/5929/thumbnail.jp

Negotiating place: an exploration of the educational potential of practising spatial design with primary and secondary pupils in three schools in England

This thesis investigates the educational potential of practising spatial design within primary and secondary schools in England. Four gaps in the literature were identified: the possibilities of children engaging pro-actively in the relationship between architecture and education; a theoretical and empirical understanding of ‘negotiation’ as a model of transformative participation; accounts of participatory design that interrogate and make visible the messy and complex; and qualitative analytic approaches that are relational and spatial. The thesis first develops a relational understanding of the practice of spatial design as inescapably contingent and political, able to operate in both dominant and nondominant modes, each with different educational purposes and potentials. Second, it investigates how the mode of spatial design is operationalised through exploring empirically how different negotiations manifest and unfold during its practice, including the effects of the methods and methodology used. The empirical research drew on a Design Anthropological approach, supported by elements of Critical Art Practice, and was undertaken through the researcher’s active role in three spatial design projects, each using various design methods: explorative walks, examining precedent projects, drawing, and physical modelling. Two took place in English primary schools and one in an English secondary. In this study, material, care, and time are identified as key elements of method and approach that directly affect the mode of participation operationalised within spatial design practices. The study also demonstrates how schools continually produce and are produced-by negotiations between the human, material, policy, regulatory, and financial threads that comprise them; how these negotiations manifest and unfold during design and inhabitation through uses of material, care, and time; and how the particular qualities of materials, care, and time used are thus central to the nature of negotiations and by-extension practices of design and inhabitation. The spatial analytic approach taken shows architects and educationalists the importance of attending to what happens during spatial design, not simply its methods and outcomes, and offers a means to do so. Architects and designers will realise through this study that reflexive, attentional participation is essential to developing relational understandings of inhabitation within schools, and that serious consideration of material-, care-, and time-use is fundamental to this. The study demonstrates to educationalists and policy makers the negotiated, contingent nature of architecture and education’s relationship and thus the value of practising spatial design in schools as a means to continually raise and engage with questions concerning the how, why, and where of education.The PhD is funded by the Arts and Humanities Research Council (AHRC), under the Collaborative Doctoral Award (CDA) scheme. It is the third of three doctoral studies to unfold within a collaboration between Dr Catherine Burke – an historian of education in the Faulty of Education at the University of Cambridge – and Dominic Cullinan – a practising architect and partner at SCABAL, a small architecture practice specialising in the design of educational environments, with a focus on schools