Abstract: To investigate the influence of importance degree on inventory allocation of spare parts for civil aircraft, the single-echelon initial inventory optimal allocation model was established based on the theory of Boeing and Airbus models. And the decomposed-coordinated marginal analysis method was proposed combined with the marginal analysis method, to implement inventory optimal allocation for expendable, rotable and repairable parts. Firstly, the procedure of single-echelon initial inventory optimal allocation for spare parts was elaborated under considering importance degree. Secondly, the initial inventory optimal allocation model with the fleet availability as the optimal objective, the spare parts cost and the support probability as the constraints was constructed. Thirdly, the decomposed-coordinated marginal analysis method was applied to accomplish the solution of the single-echelon initial inventory optimal allocation model of spare parts. Lastly, the spare parts of civil aircraft door system as the study object, initial inventory optimal allocation of spare parts was finished. Through the analysis results, the initial inventory optimal allocation for each spare part, the cost 170684.61 dollars and the fleet availability 0.9999 are obtained in the condition of satisfying constraints. Through the comparison of traditional inventory optimal allocation of spare parts, the developed method with importance degree is validated to be feasible and effective.

Key words:  importance degree, spare parts of civil aircraft, single-echelon initial inventory optimal allocation, decomposed-coordinated marginal analysis method