This paper aims to develop a method to analyze causes and to solve a late completion problem of aircraft engine maintenance jobs in a maintenance, repair, and overhaul (MRO) company. It applies fuzzy PERT/CPM methods that can determine realistic completion times and a schedule of engine maintenance jobs and develops a fuzzy resource requirement (FRR) method to determine whether the available resources are enough to conduct the maintenance activities according to the schedules. A case study is conducted in an MRO company in Indonesia. The results show that when the fuzzy activity times are estimated from real data, the fuzzy PERT/CPM methods can accurately predict the completion times of engine maintenance jobs. However, most jobs have high possibility to be completed late. Corrective actions are proposed to reduce activity times of five activities to make all maintenance jobs completed on time. Moreover, the developed FRR method is effective to evaluate that current available resources are sufficient to conduct all maintenance activities according to the schedules.