When the Wright brothers built their first plane, its construction was straightforward. A simple 12-horsepower engine powered the 40-foot-wide aircraft, which was made mostly of fabric and wood. The plane’s most technologically advanced component was its mechanical control system, which used pulleys and levers. Today, planes are in many ways more like flying computers. And the PCBAs of aerospace electronics have become as integral to aerospace technology as the pulleys and levers of the Wright era.
PCBAs are used in a variety of aerospace vehicles, including planes, satellites, and space shuttles. And because of the demanding conditions of air and space travel, and the serious consequences of a component failure, the manufacture of PCBAs destined for this industry must adhere to the highest standards. Whether enabling a plane’s collision avoidance system or providing satellite communication, PCBAs used in aerospace technology must perform within strict parameters.
Material and Manufacturing Considerations for Aerospace Technology PCBAs
PCBAs destined for aerospace technology are a special breed, required to withstand the harshest of conditions, in situations where failure can be catastrophic.
The requirements for PCBAs used in aerospace technology are similar to those for car electronics—with the important distinction that operating conditions are much harsher. PCBAs used in aerospace applications must hold up to extreme vibration and intense temperature fluctuations. And, unlike car electronics, routine maintenance isn’t as simple as a trip down the road to the local mechanic. For example, once launched, satellites are rarely repaired, because of the prohibitive cost. For this reason, reliability is an essential quality for PCBAs used in aerospace technology.
To meet the high demand for reliability, manufacturers use materials that are specific to aerospace technology. Whereas a traditional PCBA application might incorporate a copper weight of one ounce per square foot, aerospace PCBAs need heavier copper—at least three to four ounces per square foot—to achieve higher current-carrying capacity and greater heat dissipation.
Specific manufacturing methods are also required to produce aerospace PCBAs that can withstand harsh conditions. Conformal coating—a thin protective polymeric film that is applied to PCBAs—is especially important in the aerospace industry. This breathable coating allows moisture to escape while still protecting the board from contamination. It also provides electrical insulation, enhances reliability, and prevents failures such as current leakage and corrosion.
In addition to using conformal coating, aerospace technology manufacturers often press component pins to the circuit board rather than simply soldering them. This press-fit technology helps a PCBA hold up better to extreme vibrations. Additionally, this approach enables the PCBA to withstand thermal cycling—the back and forth between extreme temperatures that planes experience.
PCBAs destined for aerospace technology are a special breed, required to withstand the harshest of conditions, in situations where failure can be catastrophic. This is why adherence to best practices is especially critical for this industry. If a PCBA isn’t able to withstand high levels of radiation, for example, it will damage easily, since there is no atmosphere in space to absorb high-energy particles. And this is just one of many considerations that PCBA manufacturers must contend with.
So how can you be sure your company is meeting these high standards? And how do you show your aerospace customers that they can rely on your PCBAs? In a nutshell: Test and certify.
Perform Proper Testing
To be successful, manufacturers of PCBAs used in aerospace technology must prioritize quality control. One way to do this is to properly test PCBAs under a variety of harsh conditions. For example, testing for temperature variations is important, as aircraft cycle through extreme temperatures multiple times a day, reaching an exposure of -50 degrees when at 10,000 feet. In addition to extreme temperature variations, other variables include pressure changes, radiation exposure, and vibration. Below are tests that should be performed on any PCBA designed for aerospace use.
- Peel-Off Test: This test evaluates the adhesion strength of coatings, such as conformal coatings, to the circuit board surface.
- Drop Test: Dropping the PCBA from various heights simulates sudden impacts or vibration during flight and enables manufacturers to assess mechanical robustness.
- Thermal Aging: Exposing a PCBA to elevated temperatures for extended periods of time simulates long-term aging, testing the board’s durability.
- Pressure Test: This test evaluates the PCBA’s ability to operate under high-pressure conditions such as high altitudes.
If your company lacks any of these testing capabilities, consider teaming up with a contract manufacturer. A good third-party partner can be a great resource as they will have the design-for-excellence (DFX) capabilities to meet your design and testing requirements. Further, an experienced partner can ensure best-in-class manufacturing by having SMTA-certified engineers in house.
Follow Aerospace Technology Standards and Obtain Certifications
Because there is little room for error, manufacturers of aerospace electronics must adhere to exacting standards that address safety, testing, and other considerations.
The gold standard for the manufacture of machines and parts for the aerospace industry is AS9100. This standard emphasizes risk identification, assessment, and mitigation, and has requirements specific to the aerospace industry for such factors as airworthiness, safety, risk management, and product configuration.
Many aircraft manufacturers, defense contractors, and suppliers worldwide require AS9100 certification or compliance as a condition of doing business. Adhering to this standard—or using a third-party manufacturer with AS9100 certification—provides consistency, reduces verification audits, improves supplier performance, and cuts oversight costs in the manufacturing process.
IPC Class 3 is another important set of standards, as they ensure the highest level of quality and reliability for PCBAs—essential for boards that are used in high-stress applications such as aerospace technology. These standards ensure continuous, uninterrupted performance and are crucial for creating high-reliability electronics where any amount of downtime is unacceptable. One key standard in this class is IPC-6012. Both IPC-6012, and the related standard IPC-A-610, should be met when producing class 3 boards. An addendum to the IPC-6012 standard, known as IPC-6012 ES, specifically addresses requirements for rigid printed circuit boards used in space and military applications.
Don’t Forget Registrations
Beyond certifications, you must also consider necessary registrations. For example, companies working on defense-related aerospace projects need to have International Traffic in Arms Regulations (ITAR) registration. ITAR registration is not a certification. Rather, it is a legal requirement to register with the U.S. Department of State’s Directorate of Defense Trade Controls (DDTC). Registration helps the U.S. government control sensitive military technology by restricting physical components—and the knowledge of how to produce those components—from access by non-U.S. entities.
ITAR registration is mandatory for all individuals and companies involved in manufacturing, exporting, temporarily importing, or brokering defense services. To comply with ITAR, you must make sure that all your staff are either U.S. citizens or qualify for an exemption by meeting certain criteria for residency and proof of independence from foreign influence. In addition, any third-party partners you work with on sensitive products must also be ITAR-registered.
Violating ITAR regulations can have serious consequences, including:
- Revoked contracts – ITAR registration rules are strict, and ignorance of these rules is not accepted as a reason for non-compliance. Companies that do not fully comply with ITAR requirements may lose contracts.
- Fines/loss of aircraft – Non-compliance can also result in financial penalties. Organizations, as well as individuals, can face fines of up to $500,000—per violation. Additionally, any vessel, aircraft, or vehicle involved in the non-compliance issue may be seized or forfeited.
- Criminal charges – Depending on the violation, consequences go beyond civil penalties. Certain types of regulatory breach are considered criminal and carry fines of up to $1,000,000 per violation—and up to 10 years in prison for the guilty parties.
Where Do I Start?
- The Federal Aviation Administration (FAA): This U.S. government agency oversees the manufacture of aircraft and their components. It also evaluates new technology. While the FAA is primarily responsible for overseeing civil aviation, it also has a specific branch—the Military Certification Branch—which is dedicated specifically to aerospace and military certification.
- International Aerospace Quality Group (IAQG): The IAQG is a cooperative global organization focused on improving quality and reducing costs throughout the aerospace supply chain. This nonprofit develops standards, such as AS9100, and creates guidance materials as a resource for companies to use throughout the supply chain.
- Aerospace Industries Association (AIA): The AIA is a trade organization for the aerospace industry, representing manufacturers and suppliers. While the AIA does not directly certify organizations, it does provide publications and guidance documents to help members navigate the strict certification and regulatory requirements of the industry.
- IPC: This global association was founded in 1957 by six printed circuit board manufacturers. The association’s mission is to help OEM, EMS, and PCB manufacturers; cable and harness manufacturers; and electronics industry suppliers to build better electronics.
Reducing Your Risks
Aerospace technology companies require reliable, high-performance PCBAs manufactured to exacting standards. Meeting these standards can be a challenge, which is why it sometimes makes sense to partner with a third-party manufacturer who has the necessary registrations and certifications. In addition to ensuring your boards comply with the proper standards and regulations, the right partner can reduce your supply chain risk by sourcing quality parts at competitive prices, and can even help you streamline your manufacturing process—without sacrificing the high reliability and durability required of aerospace technology PCBAs.
