ادغام معیارهای بهره وری هواپیما در مشکل تخصیص دم

We present an optimization framework that minimizes aircraft fuel consumption and emissions through a redesigned tail assignment process. In this fleet specific aircraft assignment, we reallocate aircraft such that fuel efficiency is matched with the fuel productivity of a line-of-flight. We demonstrate substantial fuel cost-savings using a multi-commodity flow network formulation. Realizing that a post aircraft routing, fuel-based aircraft assignment has the potential to alter the pre-existing flight plan, we reformulate the problem within the context of a Pareto-efficiency frontier. Within this framework, we explore the trade-off between fuel savings and three other variables: the number of line-of-flight changes, the number of schedule changes and the combined aircraft utilization. The resulting Pareto-efficiency curves serve as a decision management tool to allow operations managers to determine the most desirable level of fuel savings, while choosing either an acceptable number of changes to a pre-existing schedule or setting a minimum aircraft utilization level.

The cost of jet-fuel constitutes a major portion of an airline's operational expense. According to the US Bureau of Transportation in 2010 jet-fuel cost $24,791 million to serve the domestic US market. In 2010, fuel costs accounted for 30% of the operating costs for Delta Airlines, which is equivalent to $0.038 per available seat-mile (ASM). While fuel costs are generally of interest to airlines, aircraft efficiency also has environmental impacts. It has been argued that roughly 70% of aircraft exhaust is in the form of CO2, as well as other environmentally harmful gases. Thus attempting to maximize aircraft efficiency has additional environmental benefits, especially as air-travel is predicted to grow by as much as 50% by 2025 (Economist, 2009). Here we reformulate the tail assignment problem to capture assorted aircraft fuel-efficiencies and thus reduce overall fuel consumption of a flight plan.

This article examines the effectiveness of using fuel efficiency information when performing the tail assignment as part of airline planning processes. We provide an optimization framework that while quite effective in terms of providing significant fuel savings, is relatively easy to implement in practice. Our proof-of-concept demonstrates that fuel-savings and reductions in emissions are possible with little interference with the planning process through a line-based optimization model. Even with such a restrictive model in which the lines-of-flight cannot be altered, our approach finds significant potential fuel-cost-savings. Further, we demonstrate additional savings for a single fleet when providing increased flexibility in the flight-based assignment model.