Incorporating aircraft efficiency measures into the tail assignment problem

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.