This paper presents a two-stage study involving the analysis of an assembly line using discrete event simulation model and the optimization of the system`s working conditions through simulation optimization. The line considered in our study is a newly designed line for the production of recently received helicopter orders in an existing factory. The orders consist of different models, making it crucial to plan according to delivery dates and ensure timely delivery. Due to the complexity of the system and the stochastic nature of the processes, simulation technique is employed in the first stage. In the optimization phase, the Taguchi method is integrated with the simulation model to optimize overall system`s working conditions. This methodology allows for the exploration of the performance of the newly established mixed-model assembly line and its variable workforce. It facilitates the determination of optimal operating conditions with reduced cost, time, and effort ensuring that each model helicopter is produced on schedule.