Recoverable inventory systems with time-varying demand

In this article, a simple analytical solution to a recoverable inventory problem in which the demand is subject to a non-stationary failure process is derived. The resupply distribution is arbitrary and the repair distribution is assumed to be expotential. Under a designated service level, the number of required spares is determined both at the flight lines and the repair facility. The model developed should be of value to companies involved in maintaining inventories of high-value items, as in a spare-provisioning activity for commercial aircraft fleets.