A time–space network model for unit load device stock planning in international airline services

Unit load devices (pallets, containers, etc.) are used to move luggage and air cargo on wide-bodied aircraft. This paper examines a case study of the number of devices needed by an airline for international scheduled services. Unit load device movements between airports require planes to load and deliver. The stock of the unit load devices is thus influenced by the airline’s scheduled services. Based on a recurring weekly schedule, this study develops a time–space network to formulate mathematical programming models for minimizing device quantities. This model is applied to assess the preparation level of unit load devices for the various service networks for a Taiwanese airline.

Research highlights
► The paper develops an optimization model for unit load device (ULD) capacity (containers, pallets, etc) used on wide-bodied aircraft.
► The study looks at optimal mixes of ULD types as well as overall capacity considering such things as aircraft fleet composition, damage to devices, and the use of centrally located repositioning facility.
► The model is tested based on the activities of EVA Airways and suggests considerable savings in ULD capacity is possible.