The Not-So-Obvious Parts of Avionics Engineering
Rishi shares his thoughts on an often-overlooked field: avionics integration!
When most people think about avionics engineering, there are a few obvious things that pop into mind: hardcore math to figure out component sizing, the intimidating logical design, the labyrinth that is PCB routing, assembly of boards, and the hundreds of lines of code required to run everything. There is an abundance of literature and online resources where you can find detailed guides on developing fancy avionics yourself. You can apply those same techniques to your personal projects, such as high-powered rockets. I am writing today to tell you about some of the things that I do on a daily basis that aren’t talked about as much but are required for having great avionics systems.
Hello everyone! My name is Rishi, and I am currently an Avionics Integration Engineer at ABL Space Systems. I graduated from the University of Illinois Urbana-Champaign in May 2023 with a bachelor’s degree in aerospace engineering. While there, I worked on the avionics systems for the Spaceshot project at the Illinois Space Society.
If you are not familiar with ABL, here is a rundown. ABL is a small satellite launch start-up working on designing portable launch systems (vehicle and ground). In this case, portable means fitting all large assemblies into standard shipping containers to transport to any available launch site to set up shop. You can read more about the company on our website and our blog.
As I mentioned before, there are a lot of things that come to mind when thinking about avionics engineering. Although those topics are very important and are the building blocks of the whole system, there are a lot of things outside of low-level design that are critical for running high-performance avionics. Due to my role as an avionics integration engineer, I am not really the one designing the low-level architecture of the avionics. In fact, my role is really separated into three different categories: high-level design, integration, and operations.
First looks
Let’s talk about the high-level design portion first. During large design phases of projects, I spend most of my time assisting design engineers, both electrical and mechanical, with questions they may have about the form, fit, and function of their components. When creating parts that are needed in larger assemblies such as a launch vehicle, engineers must understand how parts are going to fit together in the real world, which is not always representative of computer models (we really do try). Since most of what I do outside of design is manufacturing, I have a very good grasp on the state of the as-built systems and, thus, what is and is not possible. Providing this perspective to design engineers prior to sending their parts out to be built is critical so that parts work first try and do not require further rework or revisions when we get to the integration phase (which could be weeks or months since the part was designed). On a high level, some of the things I help review are the CAD models and part drawings for harnesses and avionics boxes/trays. I love this part of my job because I get to have a stake in design even though I am not considered a design engineer. It allows my voice to be heard before we run into problems down the line.
As mentioned above, one of the major part families I contribute to the most is wiring harnesses. Just like all other parts of the launch system, harnesses also have drawings that are reviewed and released before building can begin. The image above depicts a typical harness drawing called a formboard. The cool thing about formboards is that they are 1 to 1 scale drawings, meaning you can take the materials listed on the bill of materials and form them to the printout and have a complete harness. I have worked closely with both harness design engineers and avionics technicians to perfect the way we use formboards so that we have fewer and fewer non-compliances and faster builds.
The Job of a Fixer
Integration is next on the list! As my job title depicts, most of my time is spent on the manufacturing and integration side of projects. Partially, I like to tell myself that I am a fixer, one who comes in during tough times and makes things work. One of the major responsibilities within manufacturing is creating plans on how to build components, which, for me, is mostly harnessing. In my job, harnessing is the wiring assemblies required to talk from one device to another within the launch system. Typically, vehicle harnessing is optimized for weight, while ground harnessing is optimized for handling. Due to the locations and environments harnesses are designed for, I am always thinking on my feet about what the best solutions are. On top of that, a portion of my job is figuring out how to build stuff faster and more efficiently while reducing the occurrences of non-conformances. Non-conformances are any deviations that exceed the design tolerances of a part and may cause big headaches down the line. Similarly, writing good plans for integrating components into their next-level assemblies is very important for maintaining timelines. It can be tough and frustrating when you are building something for the first time and learning as you go. The best part of my job is the ability to be super hands-on with flight and non-flight hardware. Since I am hands-on with hardware, I get to see exactly how things are being made and can take things I notice back to design engineers to make their designs better for the next time. It is also just really cool to touch hardware that you know is going to space.
Although not a launch vehicle, Europa Clipper and almost all spacecraft go through tough integration periods where things do not fit together like initially planned. As you can see from the image below, the avionics system is so tightly integrated into the spacecraft that even the slightest deviation in harness length could cause collisions with other parts. Luckily, as you build more and more of the same system, you realize how to mitigate the chances of something like that occurring each time.
Highest Stakes with the Biggest Payouts
Lastly, but certainly not the least significant, is my work during the operational phases of projects. At the end of the day, I am working on projects that end with something going to space, and everyone wants to make sure all the systems are working correctly prior to pressing the buttons that can make or break your day. Once the systems you are working on are closed up, you cannot look at something directly and know if it’s working. Since all the assemblies I work on are integrated very tightly together, making sure all components work starting from their lowest integration level up to the final installation is important. This includes sensors such as pressure transducers, resistance temperature detectors, thermocouples, and more. Planning out and performing these checkouts are something I do daily and can be as simple as measuring a resistance between two points or something more complicated like measuring signals on an oscilloscope. Performing and documenting these checkouts are critical to help troubleshoot issues if they come up later down the line. I cannot forget to mention the great bonds formed with your team during the operation periods of projects. You will go through a lot together, and having trust within your organization is important to make it through safely, which is why I love traveling to our launch site in Kodiak to participate in operations leading toward the launch. A good video that I always look back at is this one made by ABL, giving the viewers a quick glimpse into what it takes to get through a first launch campaign.
Takeaways
Overall, designing and implementing large-scale avionics requires extensive teamwork from the electrical, mechanical, software, and integration teams. Here are some tips from some crazy experiences I have had in my very short career so far.
Design engineers, talk to your manufacturing and integration engineers before releasing a design to ensure it’s possible to build and integrate it. You don’t want them to yell at you after the fact when things don’t fit together.
Integration engineers, don’t be afraid to tell your design engineers something might not work, even if you only have the slightest hunch. The few extra minutes discussing a potential problem point may save you days later down the line.
Don’t overlook any odd numbers during the checkouts you may perform in your career. The smallest deviation from the nominal can sometimes be a point of concern. Point it out even if it stops operations as its better to be safe than sorry.
For those of you unsure of what you may want to do in your career, I think integration and manufacturing is a great first place to look since it will open your eyes to common design problems, which you can avoid if you switch over to being a design engineer (that’s my plan at least).
Thanks for the opportunity to write about, as the title implies, the not-so-obvious jobs within avionics engineering. I hope I was able to show you what it takes to design and implement large-scale avionics and maybe even inspire some of you to join the side of Avionics Integration. If you have any questions, please feel free to reach out to me on LinkedIn!
— Rishi Patel
Bonus Material
Although I did not speak of it much above, stage 1 engine avionics is one of the major systems I own within my team. Engines are radical systems that truly blow my mind no matter how often I see them fire off in the desert. Below is a great video my company published showing a recently built engine firing off 22 times in a row.
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