What does it take to qualify an additive part as airworthy?
As any experienced engineer knows, one of the things that sets the aerospace industry apart from many others is an abundance of standards and regulations.
Working as an aerospace engineer means having to navigate a labyrinth of procedures, rules, specifications, and certifications originating from government bodies as well as non-governmental institutions, such as the International Organization for Standardization (ISO).
What makes this task even more onerous is the continuous updating of these standards and certifications to keep pace with new developments in technology. Fortunately, there are deliberate efforts to inform the engineering community of these changes to ensure a healthy relationship between private enterprise and public safety.
FAA-EASA additive manufacturing workshops
Since 2015, the Federal Aviation Administration (FAA) and the European Union Aviation Safety Agency (EASA) have been hosting workshops with aerospace engineers, materials scientists and leaders in the aviation industry to promote technical discussions and knowledge sharing relating to the qualification and certification of parts made with additive manufacturing (AM).
While these began independently, in 2018 the two agencies came together to collaborate and take turns hosting each year. Today, these workshops include hundreds of attendees representing dozens of organizations from the aerospace industry, as well as researchers and regulators.
According to the EASA, what sets these events apart from other AM industry events, such as AMUG or RAPID + TCT, is their focus on both immediate regulatory issues and emerging technical issues. This is partly realised through the continuation of working groups from previous workshops throughout the year. For example, the 2025 FAA-EASA AM Workshop will see four working groups continue from the Workshop in 2024:
- WG1: Qualification of Additive Manufacturing (AM) Parts of No, or Low Criticality
- WG2: Fatigue and Damage Tolerance/NDE for Metal AM
- WG3: Machine Monitoring – Developing a Five-Year Plan to Allow EASA/FAA Acceptance
- WG4: Part Classification for AM
In addition to their own agendas, these working groups provide feedback to one another through debriefs and commentaries during the workshops. As an example, last year WG4 noted that the singling out of AM parts for classification in WG1’s debrief could hinder adoption by reinforcing the perception that using AM automatically results in taking on higher risk compared to traditional manufacturing technologies.
Examples of FAA and EASA efforts to certify 3D printed parts
While it’s certainly not the only channel through which these governmental bodies work towards certifying AM parts, the FAA-EASA AM Workshop offers considerable insight into this process. In the most recent meeting – in September 2024 – the Workshop reviewed EASA Certification Memorandum CM-S-008 Issue 04, which pertains to additive manufacturing in aerospace applications.
These documents are intended to clarify the EASA’s general positions on the specific initial airworthiness, validation, continuing airworthiness or organizational items. As such, they aim to provide guidance or complimentary information for compliance demonstration. While not intended to introduce new certification requirements or modify existing ones, they’re nevertheless useful for aerospace engineers working with leading edge technologies, including additive manufacturing.
In the case of CM-S0008 Issue 04, the document includes reference materials to other relevant standards, such as ASTM F3572-22, which covers part classifications for AM parts in aerospace applications, in addition to outlining EASA certification policies for the design, manufacture, maintenance and repair of AM aerospace parts.
Most recently, one tangible result of the FAA’s efforts to certify 3D printed aerospace parts can be found in GE’s new Catalyst turboprop engine, which was certified under the Federal Aviation Regulation (FAR) Part 33, which pertains to airworthiness standards for aircraft engines. According to GE, the engine contains multiple components made with additive manufacturing and the certification itself involved more than 23 engines and 190 component tests.
Examples such as these demonstrate how complicated certifying 3D printed parts for airworthiness can be. Fortunately, while the pace of technological development can be a barrier to certification and re-certification, it can also make them more attainable.
This is encapsulated in one of the leading issues in recent FAA-EASA AM Workshops: the question of in-process monitoring for AM. While the consensus is that current machine monitoring technologies need further development before they can be used to qualify flight-worthy components, there is also general agreement that these will be an invaluable tool for supporting qualification as the technology matures.
