An Investigation of Value Modelling for Commercial Aircraft

Abstract

One of the issues with commercial aircraft design is that most of the methods of developing and propagating requirements allow for nominally satisfying but less than ideal designs to be produced. There is a significant body of work that illustrates the issues that are inherent with the standard requirements flow-down approach. As an attempt to address this, a series of approaches variously named Value-Driven and Value-Centric Design have been proposed. In looking at commercial aircraft and engine design and operations several authors have suggested using a simplified Value model known as Surplus Value. This paper investigates the derivation of and assumptions that are inherent to the standard surplus value formulation. Further, several interesting and potentially useful outcomes of the standard model are investigated including the relationship with discount rate and maximum used programme duration or product life. Lastly, this paper attempts to remove one of the most restrictive assumptions in the basic surplus value formulation. This results in a more general formulation that incorporates basic sales and operating leases plus the ability to provide managed services. The resulting model is more general, but does require more user information to use.