Abstract: Scientific and proper ration of spares is a significant problem because the amount of spares can not only affect equipment maintenance and overhaul but also its operational readiness. The conventional model for calculating the demand of the spares is the probability model; however, the distribution parameters in the probability model usually contain uncertainties to some extent. This article investigates a new method for calculating the demand of the spares for cases when the distribution parameters in the probability model are uncertainbutbounded. According to the classification of aviation spares, the probabilistic interval approach for determining the demand of aviation spares is proposed for conditions when age distributions are exponential, normal, and Weibull, respectively. The proposed method can solve the ration problem of aviation spares and ensure the satisfaction of supporting rate when the distribution parameters are uncertainbutbounded. Moreover, with this method the level of aviation integrated support can be improved. Finally, a numerical example is considered to illustrate the efficiency and practicability of the proposed method.

Key words: equipment, amount of spares, distribution functions, Taylor series, probabilistic interval model, supporting rate