Certification and Application of Additive Friction Stir Process in Aeronautical Structural Repairs

Conference Abstract: The study documents the successful test and certification program conducted for the structural repair of the Bell Helicopter model 205/212/412 Main Transmission Case. The repair design, utilizing the patented Additive Friction Stir deposition process (MELD® ) has garnered approvals from TCCA, FAA, and EASA.

A significant breakthrough in structural component repair, the process, proves to be particularly valuable for metals incompatible with fusion-based methods. After extensive experimentation with various repair processes, including cold spray, MELD emerged as the sole process capable of (1) processing magnesium and (2) achieving the required bonding and material density. Furthermore, the test program demonstrated that the deposit exhibited a tensile strength equivalent to the magnesium substrate.

With well-established processes, stringent quality controls, and proven structural characteristics of the repair, there is interest to extend the application of the Additive Friction Stir deposition process to other aeronautical components. This research represents a significant advancement in aeronautical repair technology, offering a promising solution for the aerospace industry's ongoing quest for improved structural integrity and performance.