Industry 4.0 and the digitalization of the manufacturing processes have brought new opportunities and strategies for process control and optimization. Friction Stir Welding is becoming a relevant manufacturing technology for several applications, among them the aerospace sector. This work presents the first data analysis and characterization of the Friction Stir Welding process of the Pre-Final Assembly Line of the new Ariane 6 launcher. Process monitoring data is captured and analyzed to provide predictive quality solutions for improving manufacturing key performance indicators and bring smart manufacturing and Industry 4.0 digitalization into the aerospace manufacturing sector. The results show promising performance for abnormal behavior detection, leveraging on a tailored data manipulation approach for this unique use case.