民航發動機維修範圍變異大，組裝作業時間不確定性高，夋使用特定的維修資源，並在特定時間內與飛航安全的要求下，將發動機維修完成效付航空公司，作業流程的規劃與控管且有專案管理特性。因此，本研究利用計畫評核術(PERT)，辨認發動機組裝的要徑作業，評估發動機組裝時間，並結合作業基礎成本制( ABC)所提供的作業費率計算發動機組裝成本。本研究也探討不同線範圍下對發動機組裝時間之影響，並分析趕工需求下，修護工廠採行「非原件回裝」、「增加限制資源」、「要徑作業趕工加班」三種因應策略對縮短發動機組裝時間之影響，期能作為發動機修護工廠組裝時程之依據。

There are several characteristics of civil aircraft engine MRO business. These include considerable variations in work scope, high uncertainty of activity time, requiring specific equipments and technologists, having time limit to complete, and conformity to the aviation safety regulation. Consequently, the planning and controlling processes of the assembly activities are similar to the spirit of project management. This study uses Program Evaluation and Review Technique (PERT) for identifying the critical path activities and estimating the span of engine assembly. Besides, this study applies the fares of work centers analyzed by Activity-Based Costing (ABC) to calculating the assembly costs. And the effects of different work scope on the critical path are also discussed. Finally, in order to shorten the assembly span, this study proposes three crashing strategy: (1)assembling the engine by sparse modules; (2)purchasing more critical equipments; and (3)crashing on critical activities. We hoe that this study can help engine maintenance plants to evaluate their assembly span and probability.