3.9 Lessons Learned on Supportability and Repair of Composites

Major technological advances using composite materials have been achieved in the last 50 years leading to the introduction of these materials for the first time in heavily loaded transport aircraft wing and fuselage structures. To ensure the safety and continued airworthiness of composite airframe components, challenges associated with maintenance and repair must be addressed and a robust infrastructure for supportability must be established. To address these challenges, repairability must be considered during the design of the structure, taking into account the lessons learned from the service history and the constraints of the in-service environment. Factory systems, requiring autoclave conditions for optimum performance, cannot be used in maintenance depots. Out of autoclave (OOA) repair systems and associated processes must be carefully developed and substantiated during the design phase. This chapter highlights key lessons learned from research and development (R&D) work on repair manufacturing processes and provides recommendations pertaining to best practices for bonded repair technology.