A Multi-item, Multi-echelon Inventory Allocation Model for Aircraft Spare Parts Based on VARI-METRIC

摘要

To maximize the system availability for a fleet of airlines, aircraft with optimal spares investment, a inventory model based on VARI-METRIC is proposed according to the process of use, transport and repair which is based on system approach for determining aircraft spare parts stock level in a multi-echelon system. First of all, the relationship of availability and backorders is proved and negative binomial distribution is chosen to describe the backorder distribution when the value of mean-to-variance ratio is more than one. Then, with the target of minimum the total expected backorders for spare parts and cost constraint, the marginal analysis method optimization is applied. Finally, two examples were given and proved that the model using negative binomial distribution is reasonable and engineering applicative.