MINE : Multi-Indenture NORS Evaluator.

A discussion of MINE, a single-base evaluation model developed for application to the F-111 aircraft for a multi-indenture problem, where demand on a first-indenture line replaceable unit (LRU) eventually causes second-indenture demands for one or more modules that are components of the LRU. Since the model is evaluative, inputs include item stock levels, demand rates, average repair times and resupply times. Although an optimization model to determine stock levels that minimize the number of NORS aircraft subject to a budget constraint would be preferable to the evaluation model, the study shows that an optimization model is not mathematically tractable because the criterion function is not separable into independent item calculations. However, an example using F-111 data indicates that if the METRIC model (RM-5078) is used to optimize stock levels, the resulting NORS rate is within one percent of the minimum NORS rate achievable with the same budget. 44 pp. Ref.