The idea of a digital twin (DT) has grown in popularity as a way to keep track of product-related data throughout the product's life cycle. Health monitoring systems are one of the manufacturing system areas where the digital twin (DT) has been proposed and deployed. To continuously monitor wear, anomalies, deformation, and the manufacturing system's overall reliability, these systems employ digital twin technology. The use of digital twin technology to predict the life of aircraft main bearings is examined in this chapter. The main bearing is a vital component whose failure can have catastrophic consequences in the aircraft propulsion system. Using the capabilities of digital twin technology, engineers may create virtual replicas of the main bearing and monitor its performance in real time. Because preventive maintenance techniques are made possible by this predictive capability, downtime is decreased and bearing lifespan is increased. This chapter covers the crucial stages of developing a digital twin for an aircraft's primary bearings, including data collection, model creation, and predictive analytics. Additionally, it examines the challenges and potential advantages of using digital twin technology for aircraft maintenance.