Annalisa Cesaro and Dario Pacciarelli. Analytical techniques for assessing the performance of airport maintenance activities

Abstract. We provide a new approach for computing the performance of airports corrective maintenance activities, in particular in systems with lateral transhipments in case of one-for-one ordering policies, no negligible transfer times and state dependent demand. The approach is motivated by the operational problem of a large logistics company, in charge of the maintenance of 38 Italian Airports. Strict requirements of equipment operational availability and long repairing times make necessary to maintain high stock levels of spare parts, thus involving high inventory costs. While a two echelon inventory policy without lateral transhipments is currently applied by the company, more flexible  models with lateral transhipments might help to reduce inventory levels, Wong et al. (2005).
In this work, we model a single echelon policy with extensive use of lateral transhipments and emergency shipments similarly to Wong et al. (2005). With such emergency shipments, no demand arriving at any base is backordered. The resulting model is a queueing network with zero buffer and lateral demand, which may be modelled exactly through a Markov chain model.
The blocking probability of this network models the probability of spare part unavailability. We show that the probability of spare parts unavailability in the network can be easily computed using an equivalent  Birth-Death model.
The objective of our study is to evaluate different approximation techniques for computing the system performance rather than solving the total Markov process, and to compare them with the exact computation in terms of error, memory occupation and computation time. Computational experiments, carried out on a large sample of practical instances, are also reported.

[1] Wong, H., G.J. van Houtum, D. Cattrysse, D. van Oudheusden. 2005,
"Simple, efficient heuristic for multi-item multi-location spare parts systems with lateral transshipments and waiting time constraints", Journal of the Operational Research Society, Vol 56, pp 1419 - 1430.