Maintainers from the 60th Maintenance Squadron and 349th Aircraft Maintenance Squadron from the Travis Airforce Base, along with Engineering and Engineering Support contractors from the C-5 System Program Office out of Robins AFB, Georgia, began maintenance last month to modify an aerodynamic fairing for a C-5M Super Galaxy by incorporating printed 3D parts.
The printed blocks and wedges, supplied by the USAF Rapid Sustainment Office, provide internal support to the C-5 hump panel covering a wing splice, as described by Clay Elliott, a C-5 structural engineering subject matter expert with the C-5 SPO.
When a Travis C-5M landed in Charleston AFB, South Carolina, during a mission in December 2022, the crew discovered, during a post-flight inspection, that a section of the hump panel was missing. “The technicians went up on the wing, and that’s when they discovered that there was a massive delamination of the phenolic (blocks),” said Elliott. The blocks provided internal support to the C-5 hump panel which allowed proper aerodynamics over the wing, and in this instance, made the aircraft non-mission capable.
To get the aircraft fixed as soon as possible, Elliott proposed to integrate the 3D printed parts made from Antero 800NA, a new thermoplastic material, into the aircraft repair. After a team of maintainers fixed the panel at Charleston, the aircraft was flown back to Travis for further maintenance.
The process involved completely removing the legacy parts from the plane and re-bonding the new 3D printed blocks and wedges to the aircraft and re-installing the panels. “It’s pretty intense work with regard to getting all this stuff off, then getting it clean without causing damage,” said Elliott.
According to Elliot, the Antero material has shown promising results and the material appears to be impervious to natural elements. “For what we’re doing, 3D printed Antero seems to be a really solid replacement for phenolic,” said Elliott. “All the aircraft we’ve worked on so far with these improved materials and processes -we’ve haven’t had any issues.”
Todd Hicks, 60th MXS Aircraft structural maintenance supervisor, highlighted how the new technology has expedited some C5-M maintenance and repairs. Integrating 3D printing technology resulted in faster turnaround times and reduced costs. It helps to provide the option for the 60 MXS to produce some parts on demand, rather than go through the lengthy process of sourcing parts from third parties, if a part is unavailable locally.
According to the article published by Travis Airforce Base, traditionally, spare parts for the C-5M have been expensive and time-consuming to produce, as they required specialized tooling and long lead times. However, the use of 3D printing has allowed for the creation of these parts in a more efficient manner, said Hicks.
“Hopefully, this is a one and done and it works great so we never have to revisit this again from the aircraft,” said Hicks. He emphasized also how thousands of maintenance hours could be saved once the whole fleet of C-5s receives the new 3D blocks and wedges.
The integration of 3D printing technology into the maintenance and repair of the C-5M has had a significant impact for the US Air Force. According to Elliot, faster repair times and the potential for cost savings have all combined to make the aircraft more operationally ready and cost-effective.
