Concurrent Aircraft Design and Variable Resource Allocation in Large Scale Fleet Networks

Abstract

This paper presents and solves a class of concurrent aircraft design and allocation of variable resources. In particular, the paper considers two large scale airline fleet allocation problems where one aircraft of the airline fleet also needs to be designed. The paper presents how to mathematically formulate such a class of problem, how to efficiently solve such a coupled problem, how to numerically solve the problem, and what conclusion to draw from the proposed numerical solution. Airlines are complex industries that incorporate multiple dissimilar elements. These elements spatially and temporally evolve to achieve multi-objective functionals. These evolutions occur as results of both collective aggregation and individual dynamics. An airline fleet consists of a collection of different types of aircraft. Different aircraft types serve different purposes. One type of aircraft may be appropriate for a short-range flight. Another type of aircraft may be developed to serve a long-range flight carrying a large number of passengers. The same aircraft type may be configured differently by an airline or different airlines. These differences are necessary to support airline’s objectives. One important objective, among other airlines’ objectives, is the economic objective. Typically, the most important formulation of the economic objective is to maximize profit. From the perspective of operating costs, an airline tries to find optimal resource management strategies, both for short- and long-term, cost-efficient overall system operations. One of these strategies includes a collection of flight-service route selections and fleet assignments. As these strategies are time-variant decisions, the fleet assignments are also developed for short- and long-term services and operations. Short-term fleet assignments are very likely to include existing fleet while long-term assignments may incorporate non-existing aircrafts. The problems considered in this research correspond to the long-term assignment problems that incorporate aircrafts that do not yet exist to determine if these new aircrafts will benefit the airline. One of the purposes of this research is to investigate the case of long-term fleet assignments using fixedand variable-aircraft aircraft resources and their impacts on aircraft design. Aircraft design and airline fleet allocation are traditionally developed independently. An aircraft manufacturer may recognize a need for air travel over a set of flight ranges. This recognition results from future projection analysis based on past data and trend analysis. It then develops an aircraft program along with a set of economic and operational features to be promoted to airlines. When airlines are interested, they place aircraft purchase orders, and the aircraft manufacturer proceeds with the program. The approach to develop a new aircraft pursued here is different. The formulation of designing a new aircraft is integrated along with airline long-term fleet allocation. Long-term fleet allocation incorporates dynamic aspects of various entities: costs, demands, maintenance, availabilities, and trip limits. The explorations of this design perspective, however, mainly emphasize the feasibility of the approach. Due to the lack of high-fidelity dynamic models from real problems, this research employs generic dynamic models based on various assumptions. Along with these simplifications, this research employs a generic aircraft sizing code for the purpose of aircraft design.