At Mitsubishi Heavy Industries Group, Shun engaged in customer support operations for the Japan Air Self-Defense Force, including aircraft failure investigation support, project management from on-site investigation of aviation accidents to implementation of countermeasures, and process design for IT system deployment, among other duties. Subsequently, he was involved in project management and architectural design to overhaul the logistical support operations to maximize aircraft mobility in new aircraft development, and he was also involved in the study of aircraft serviceability requirements.