Development of an airline revenue capability model for aircraft design

Typically value based approaches to the design of civil and commercial aircraft, be they net present value, surplus value, or any other utility based approach focus solely on the difference in cost between the alternatives, neglecting changes in revenue which might occur between the two concepts. Alternatively, if they do have a revenue focus, it is based upon simple relationships between payload capacity and revenue, assuming a either a fixed protfimargin or fixed yield. This approach works well when comparing two similar or closely related concepts, but falls apart when investigating more radically di erent systems, e.g. a cruise eficient short take-o and landing concept. By using a value based approach it is relatively simple to structure a decision model to incorporate changing revenue capability. However, the ability to investigate differences in design is very much dependent upon the revenue model and assumptions that are made. If the revenue elasticity is the same forthe two concepts then there is no benefi t in using a variable revenue approach. However, in the cases where the elasticity is different, the revenue approach offers the potential to more properly investigate some fundamentally different alternative concepts. © 2010 by Peter Sutcliffe & Peter Hollingsworth. Published by the American Institute of Aeronautics and Astronautics, Inc

Molecular phylogenetic analyses of Verticillium fungicola and related species causing dry bubble disease of the cultivated button mushroom, Agaricus bisporus

International audienc

Molecular genetic variation in populations of Verticillium fungicola on the cultivated button mushroom Agaricus bisporus

International audienc

Value Operations Methodology for Value Driven Design: Medium Range Passenger Airliner Validation

This paper gives insight in the development of a Value Operations Methodology (VOM) that can be used to support Value Driven Design (VDD). The VOM establishes expressions for operational value levers that are incorporated into a weighted value function. This value function is then used to optimize the design variables that are incorporated into it so that the design process is actively driven by value assessments that provide design decision metrics. However, the VOM is generic in nature and has a much wider range of influence to the design process for any engineering product. The methodology is verified by means of a case study, analyzing the value difference between the Boeing 737-200, Boeing 737-800, Embraer ERJ-145 and the Airbus 319 as part of a use-case study. In fact, the fundamental conclusion from the work presented is actually that VDD simply promotes the sustained application of the main utility values that were originally recognised but which, due to the complexity of the product and enterprise, tends to be disaggregated into isolated requirements. Ultimately, this leads to optimisation at a sub-system level and that is especially unacceptable for a complex system (with many sub-systems), whereas the re-focus of VOM helps to significantly shift the design effort back to creatively solving the main goal, rather than simply and somewhat robotically making sure the requirements are satisfied. The verification and validation work presented is recognised as indicative but the authors believe that it is extremely significant in pointing towards the potential gains from sustaining a more holistic appraisal and approach through-out the design process. Notwithstanding, the key message of the paper is the need for value modelling within engineering so that we are in control of the consequences of what we are actualising, where value is realised through operational delivery and excellence! This paper has presented a broad methodology in opening up a significantly different approach to aircraft design that may well still be economically driven but incorporating drivers of a much more holistic cause: proactively rather than reactively