ABSTRACT This research aims at developing an approach to assess the probability of meeting customer service level, while considering various risk factors present in a supply chain (supply disruptions, uncertainties in lead times, labour shortages, transport disruptions etc.). The work is conducted in tight collaboration with a leading actor of an aeronautical industry. Our model enables a better management of supply chain flows by improving two KPIs of interest for the company that operates in a MTO environment: on-time delivery (OTD) and depth of delay (DOD), by varying the repartition of flows between possible production and transportation modes. Change in transportation mode is indeed considered as a risk mitigation lever leading to sustainable operations. We first collect input data, which includes data related to the characteristics of the system under study (flow diagram, data pertaining to parameters such as lead time, cost, capacity…) and supply chain risks mapping. Then, we develop a discrete event simulation (DES) model considering supply chain risks to determine the best flow repartition enabling to satisfy KPIs considered. A performance evaluation module enables to calculate the probability distribution of the chosen KPIs. Finally, a multi-scenario analysis is conducted by varying different parameters that have an impact on OTD, DOD and the total cost.