5 Considerations for EMI Shielding in Aircraft Applications

You can’t use your cell phone on an airplane, and you more than likely know the reason behind that: In the early days of cell phones, there was some concern that cellular signals could create an electrical interference with avionics and cockpit implements, creating a potentially deadly hazard.

Now, after cell phones have moved up to much higher frequencies that pose little threat to avionics, that’s not as much of a concern (although you still can’t use your phone in flight). Wouldn’t it be nice if the concerns about electromagnetic interference (EMI) in aircraft ended?

Of course, any manufacturer, engineer, designer, or another professional who operates in or around the aerospace industry knows that cell phone interference is only the beginning of the EMI concerns involving aircraft. That’s why EMI shielding in aircraft is an increasing demand and will only become more important over time. This is a subject that warrants some discussion, and that’s why we have put together this post. Read on to learn about five key considerations for EMI shielding effectiveness in aircraft applications.

Modus Advanced is a manufacturing partner to some of the most advanced aerospace and defense firms in the world, and we can be your partner, too. When you need EMI shielding gaskets and other materials that put quality first, you need Modus. Contact us.

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EMI Can Affect Aircraft in Multiple Ways

EMI can come from a wide variety of man-made sources: power line cables, ignition systems, WiFi networks, cellular networks, and much more. It can also come from natural events like lightning strikes and auroras. Unfortunately for those who work in aerospace, aircraft are vulnerable to all of the above.

Here’s the problem: Aircraft are high up in the atmosphere, which makes them uniquely vulnerable to lightning strikes and the ensuing conducted EMI that travels throughout the craft. Then, of course, you have radiated EMI, which comes from all corners of the world, enters the air, and can connect with an aircraft in flight. Finally, you have dozens of disparate systems onboard a standard commercial aircraft: positioning systems, avionics, in-flight WiFi, the potential in-flight use of cell phones, and much more.

It’s a scary thought, but there’s one more potential source of EMI: a weaponized electromagnetic pulse (EMP). The system required to point massive, signal-disrupting bursts of electromagnetic energy at aircraft as a weapon has a lower barrier to entry than you might assume, meaning it’s a potential threat to aircraft of all kinds all over the world.

Why does this matter for EMI shielding properties in aircraft applications? Because you have to have extremely effective EMI shields — shields that can withstand constant EMI and massive bursts, as well as both conducted and radiated EMI.

EMI Shielding Applications in Commercial Aircraft Are Limited

Despite the ubiquity of EMI in the modern world, you’re not going to find a ton of EMI shields on your typical commercial 737. Many of the visible elastomers on a commercial aircraft are non-EMI, instead of providing a specialized and reinforced environmental seal. 

Still, you can find effective EMI shielding solutions in commercial aircraft if you know where to look. Namely, the in-flight WiFi modules and avionics systems. The EMI shielding on WiFi modules aboard commercial aircraft goes two ways — it prevents the system from disrupting another system onboard the aircraft, and it helps ensure a steady, reliable WiFi signal for users. The avionics onboard require various EMI shielding applications to make sure their signals are never disrupted and that they are working properly at all times.

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Military Aircraft Are Heavy on EMI Shielding Effectiveness

In stark contrast to the lack of EMI shielding on commercial aircraft is the relative abundance of EMI shielding materials found on any military aircraft. These specialized aircraft are brimming with sensors, positioning devices, and even laser-guidance systems, and each must avoid both interfering with other systems and being interfered with itself.

Electromagnetic interference shielding effectiveness in aircraft is a complex prospect on its own, but when you’re discussing EMI shielding in military aircraft, the task at hand becomes much more difficult. That’s because you have to comply with MIL-DTL-83528 standards for EMI shielding. Failing that level of compliance, a design for a military aircraft will never make it off of the drafting board.

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Many Aircraft EMI Shielding Properties Are Standardized

The good news is that, particularly for military aerospace applications, many of the EMI shielding materials for use in gaskets, connectors, O-rings, and more are standardized. The bad news is that standardized materials often don’t meet the unique specifications of your design.

For example, certain aircraft applications may require an extremely low level of outgassing — one that is lower than the standardized materials approved for use in EMI shields. Or maybe your design requires a high level of microwave absorption or thermal protection against electronic devices. In such a case, you may need custom EMI shielding and materials. This fact highlights the need to work with a high-quality, experienced manufacturing partner.

Aerospace EMI Shields Face Unique Environmental Challenges

In some cases, an ideal EMI shielding material may not be ideal for EMI shielding in aircraft applications. You might assume that the best EMI shield would always win, but that’s not always the case in aircraft design.

For instance, what if the EMI shield you are designing will come into contact with jet fuel or extremely low or high temperatures? Will your chosen EMI shielding material also stand up to these environmental pressures? In many cases, the answer will be no. This is another situation in which a custom EMI gasket or another implement will likely be the only sufficient answer.

Modus: The Leader in Aircraft Electromagnetic Interference Shield Manufacturing

When you’re talking about EMI shielding effectiveness in aircraft, what you’re talking about is human lives. A system shield is a threat to those on board any aircraft, as well as the success of countless military and defense operations around the globe. That’s why EMI shielding has to be perfect in aircraft applications. 

At Modus Advanced, quality is what drives us. That makes it easy for us to uphold the high levels of quality needed for aerospace electromagnetic interference shield manufacturing, and it’s why we’re the manufacturing partner of choice for so many high-powered defense and aerospace firms. If you’re interested in partnering with us, we’re interested in hearing from you. All you have to do is give us a call at 925) 960-8700 or contact us online.