Tech Debt Burndown Podcast Series 3 E8: Georg Schleiermacher

Show Notes

Recording date: Jan 7, 2025

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Georg Schleiermacher

Chris and Nick speak with Georg Schleiermacher, former CTO of Hyperloop Spain and veteran of MTU Aero Engines, to explore technical debt in the aviation sector. Georg explains that because aero engines remain in service for up to 50 years with frozen designs, making any changes—even updating a single screw or a computer processor’s FADEC software—requires extensive, expensive regulatory recertification. This rigid process discourages minor optimizations and forces companies to carry immense legacy design debt and maintain decades of electronic spare parts to mitigate hardware obsolescence.

The conversation also details the extreme safety standards governing Class 1A engine components, such as disks, whose manufacturing processes, suppliers, and individual assembly workers must be fully certified to guarantee they never fail in flight. Addressing supply chain integrity, Georg explains how tracking documentation prevents counterfeit parts, as airlines risk losing their operating licenses if they use uncertified components. Finally, Georg shares his recent experiences transitioning to the Hyperloop industry, noting that while it is less established, it offers a unique opportunity for companies to cooperate with EU regulators to define safety standards and design requirements from day one.

Show notes (links)

Full authority digital engine (or electronics) control (FADEC)

Transcript (automated)

Nick: It’s the Tech Debt burn down podcast. I’m Nick Selby.

Chris: And I’m Chris Swan.

Nick: And today we’re joined by my friend Georg Schleiermacher. Georg, can you please introduce yourself?

Georg: [00:00:30] Sure. Thank you. I’m Georg Schleiermacher, currently working as a tech advisor, interim manager in aviation and deep tech business. And two sentences before my current role, I was CTO of Hyperloop in Spain, developing the technology for the Hyperloop transportation system. And before that, and this is my main section of experience, I was working for MTU Aero Engines 24 years. It’s among the top five engine OEMs in the world. So this is my background.

Nick: [00:01:00] And Georg and I are neighbors in Germany. And I was telling him about technical debt and he said, oh yeah. And I suddenly realized that this was a totally new thing because I fly little tiny planes, and I know there’s nothing on a little plane that cost less than $500 because the approval process of anything, even the stickers that have the numbers on the side of your plane, has to go through certification with the national organization, and it must be crazy. And so a couple of days ago, I was talking with Georg and he said, in the enterprise you make a product and you set time for a burndown of tech debt. In aviation, an engine program lasts 40 to 50 years, and the design is locked in, and every change requires regulatory approval. This is what got Georg here today. What does that actually mean?

Georg: [00:02:00] Talking about this long period of time? When the airlines decide—and I’m talking here engines only, not the aircraft—so when the airline decides on an engine type, they have a choice. Sometimes three: Rolls-Royce, Pratt and Whitney, or General Electric, or sometimes just two of them. And when they decide, the aircraft is designed around or in conjunction with the engine. So therefore, if an airline decides for Pratt and Whitney engines, the aircraft is built for the Pratt and Whitney engine the entire life. A typical stint for an aircraft in an airline is 12, 14, or 15 years. The first operator, and afterward it will be sold to an airline. So the product is in service for 50 years. And when I talk about aircraft in service 40 to 50 years, the engine on wing is exactly the same engine—not exactly the same, but it’s the same type. It’s getting refurbished and maintained. The same thing happens with the aircraft itself, but also with the engine. And therefore we have this long period of time of operational service. And therefore we are talking in the aircraft and aero engine business 40 to 50 years in service.

Nick: [00:03:00] Is that every part within the engine? So you’re refurbishing the engine, upgrading it, and rebuilding it. Is every part also certified in the same manner? So that, yes, it’s a new one, but it’s the same part that was originally put into that engine 30 years ago.

Georg: [00:03:30] Exactly. When you design a new product, you start with validation, testing, and certification, and then you get a type certificate of this particular engine. And this means you are not allowed to change anything, not even a screw or bolt. Nothing. Everything is frozen. The whole design is frozen and certified. And theoretically, if you did not change anything—which is not practical—the entire life of the product would be using exactly the same design. But this is not true in the real world, because once you have your engine out in service, a couple of months later you start redesigning parts and starting the recertification and revalidation process, which is very time consuming and very expensive.

Chris: [00:04:00] And to what extent are we talking about software here as well as hardware? I imagine everything now is built around some kind of microcontroller. To what extent is the software element of that within that same regulatory scope of needing to be recertified before an update can be pushed out?

Georg: [00:04:30] This is a very good point, Chris. The engines are FADEC engines, full authorized engines controlled by a computer. If you have a new software version, which is normal, you need to recertify. And the certification process for a FADEC in an engine is extremely complicated and time consuming. It’s not my core expertise, so I cannot give you the details about the certification of the software within the FADEC, but every software update, like a screw in the hardware, needs to be recertified in a very detailed process. And there’s another thing: when we talk about controls in the engine or when you start the assignment, you are using the top of the line computer system you have, and then you are creating your software on it. This is going to start in the engineering process, and you need a couple of years until the engine is ready for testing, and then another couple of years of certifying and validating it. So you have five, six, or seven years of developing time when you start from scratch. When you enter service, your computer is already outdated from the technology point of view, but it’s certified. So when you are going to update your processor and everything inside the computer, you need to recertify—it’s the same with the hardware. But then there is another specific point. When you are going to repair your computer of the engine, you need electronic parts and at some point in time they are not available anymore on the market because they are not going to be produced anymore—old, outdated hardware stuff. It is a huge problem. In the computer industry, you have huge quantities to build those parts, but talking aero engines, this is a couple of thousand parts, and when you are going to repair or upgrade, you are talking about a couple of hundred. This is a problem of obsolescence, especially for the computer and the associated hardware with it.

Chris: [00:06:30] So the companies end up keeping deep stock of the spares for that. If they’re making a thousand engines, do they have 2 or 3,000 replacement MCUs just sat in a warehouse somewhere?

Georg: Absolutely.

Chris: Yeah.

Georg: [00:07:00] This is old stock. This is what you are doing. And then, you are in close contact with your supply chain and suppliers of those parts, and they call you one day and say, ‘Okay, end-of-life order. Your last order.’ And then you order. There’s a strategy behind how many parts you’re going to stock. But the parts have a stock life. If the stock life is exceeded, you have to throw it away, even if the part is all right, because from the certification point of view, you cannot put outdated hardware in it. And that’s it. This is a real problem from the obsolescence point of view in this aero engine business.

Nick: [00:07:30] From what you’ve told me in the past, every change needs to be validated and certified, which is essentially doing it all over again. You don’t get a head start because it’s already out there. If you’re changing something, it’s essentially ab initio all the way back. Just restart. Chris and I have talked a lot about how technical debt is a necessary part of innovation. You want to get things done, and so you’ll get things working, then go back and fix them and make them better. But it sounds like you’re on a completely different level of expectation, especially on a new engine type or a new part type. How do you ensure that you are engaging in engineering excellence the entire way? You’re not making any shortcuts so that once you get the certification, you’re not going to find out, ‘Oh my gosh, we should have just done it like this. We could have saved $1 million per part.’ How does that work?

Georg: [00:08:30] There’s a very rigid process. In the design change process, you have a frozen design. When you think there could be an improvement to one of those parts, you start the process and say, ‘I have an idea.’ It then goes through many internal gates to take the next step, and the next. Finally, you pass five, six, or seven different internal gate reviews before anyone allows you to work on a redesign. Then the redesign starts, and during the process, it is reviewed again. Once you have the final redesigned part, validation and testing starts until you have enough data to convince the authorities, saying, ‘This is my redesign, this is my plan, and this is all the validation and testing work I have done.’ You have to lay out everything. The requirement that it is equal or better is mandatory. So you need to convince the authorities, saying, ‘This new design is equal or better’—better, obviously. And this is what is done in order to prove that it’s equal or better for certification. It is very time consuming, very complicated. Even a small change, as I said—if you cut the length of a screw, you need to recertify it.

Chris: So it sounds like there’s an awful lot of iteration and experimentation happening behind the scenes before you take that run-up to regulatory approval.

Georg: Absolutely.

Chris: [00:10:00] And that could be at a very small scale when we’re thinking about changing the size of a screw or something, but it could be at the level of the entire engine as well. And these things don’t just appear from nowhere. Designs tend to evolve from earlier designs, but there are also revolutions that occasionally come along. I know Rolls-Royce talk a lot about the fact that they grow the turbine blades out of a single crystal of the metal. That was obviously a process that didn’t previously exist, and they were only doing it because it fundamentally changed their approach to efficiency and durability. I expect they probably spent ages refining that before it actually got anywhere near building an engine around it and going through the regulatory process 100%.

Georg: [00:11:00] Yeah. And I think what you said is absolutely true. Single crystal is now standard in aviation high-pressure parts. But this comes back to our initial question about technical debt. When you have such a complicated, time-consuming, and expensive design process, it is contrary to the initial engineering way of thinking. The engineer sits down and wants to improve things. Sometimes, from the management point of view, you need to stop those engineers, saying, ‘Pencils down, guys. We are done. The design is frozen. Everything you are doing right now is good, but we cannot use it unless we have a problem we need to fix. If after a couple of thousand hours of operations we find a crack or an issue, we are forced to do a design change, and then it needs to be very quick, of course. But this typical engineering way of thinking—trying to improve things—is contrary to this very difficult design process. And this leaves lots of technical debt inside the engine, even if the engineers know there is a much better solution. We face repairs earlier than expected, or we face operational issues with a part because we understand a couple of years later that there is a much better solution, but it is difficult to bring that into the product because of this design process. So not all improvements make it inside the engines, which means from the other side, there is quite a bit of outdated design included in the engines.

Chris: [00:13:00] You just talked about pencils down, but I don’t expect any of these engineers actually use pencils anymore. So I’m imagining now a whole tech debt problem inside of the engineering toolchain where they’re using CAD software. That CAD software is running on a particular operating system, which is running on a class of workstation. How is that dealt with over the years? A lot of that software world has this forced march of deprecation going on. I expect the CAD software remains backwards compatible with old files or whatever, but does that throw up a whole bunch of challenges around, say, Windows 10 deprecation later on this year? Is there a huge problem in the industry with being forced by Microsoft to move to Windows 11, where maybe our old CAD software doesn’t run on that and we’ve got to certify a whole bunch of new stuff? To what extent do regulators poke their noses into that back office aspect of the platform?

Georg: [00:14:00] I guess this is a problem in the engineering world because, as you said, they are using different CAD systems, whatever brands they have, and changing them has a huge impact. It’s not like they can easily change. When they decide to go for CATIA, it is cast in concrete for the next couple of years working with this specific software. You’re absolutely right. You need to have your design ready for design changes and looking at old designs, of course.

Nick: [00:14:30] This was actually something that you mentioned to me and I thought it was fascinating. First of all, I’d like you to talk a bit about the classification: how a failure of a Class A component is different from a Class D component. With certain classes, the manufacturing process is also part of the certification, so you can’t even change anything on the assembly line.

Georg: [00:15:00] Absolutely. Inside the engine there are some critical parts for the engine itself during operation. The most important requirement is that if a failure occurs during flight, it’s considered a flight safety concern when debris leaves the engine casing. This is the worst thing that can happen because once debris leaves the engine casing, there’s a high potential to damage the aircraft by going through the aluminum. Behind that there is hydraulics, electronics, and other parts, and then you can really have an accident. Therefore, the most important requirement is that no debris leaves the engine when a failure occurs. Most of the parts are designed according to that, like blades; when a blade breaks internally, it is not a big issue because the debris will leave the engine through the exhaust. But there are parts, and these are so-called Class 1A parts like the disks where the blades are mounted on, that have such huge kinetic energy. When they break, they go through everything like the casing of the engine and the entire aircraft. The kinetic energy is so high you cannot contain it. Therefore, you have to make sure that these Class 1A parts will never break during operations. How do you do it? First of all, I can give you some numbers for this. For this disc, the design life is 100,000 hours or cycles. But you’re certifying it for 20,000 cycles only, building in a safety margin. This is one thing, but also—and this is what the authorities are very much after, and you just mentioned it, Nick—the production of Class 1A parts is monitored very closely. When you are producing a disk, first of all, you need to certify your whole supply chain. Suppliers also have a specific certification to produce a raw part. And then the raw part comes into the company, is produced, and built. If you are doing that internally, you have to certify the whole production process: what kind of machines you are using, what kind of tools inside the machines you are using, what kind of coolant you are using, and even the worker needs to be certified on this engine part and on this machine. Therefore, the entire process to produce a Class 1A part is completely frozen. If there is an error, you always can go back and say, ‘This part was produced by manufacturer X, Y, Z. The raw part material was from this supplier.’ You really can track it down to the single person who did the manufacturing.

Chris: [00:18:00] This gets me thinking about in tech, we’re increasingly talking about the software supply chain. Clearly, there’s a very detailed component supply chain for these things. But I have also been reading alarming stories in the past year or two about counterfeits finding their way into flying aircraft. What is the industry doing to ensure the authenticity of components as they move through the supply chain? To use an analogy, it’s like I drive a BMW, and I go to my garage to get it fixed, and they say they’re supplying me with a genuine BMW part because it came in a bag that’s got ‘genuine BMW’ printed on the side of it. In fact, that’s been made in China by a much cheaper manufacturing process, so it doesn’t work as intended. This same problem has been affecting the aviation industry because of the cost of the parts. What is happening to ensure that there’s better tracking and authenticity of components as they move through the supply chain?

Georg: [00:19:00] This is a big problem inside the aero engine world, but they handle it quite clearly from the authority point of view. Every single part can be tracked back to the manufacturer, until you are talking about fraud, where you can cheat the paperwork coming with the part. But you have to make sure when you’re going to assemble the engine, every worker double-checks the paperwork of the part. The part goes through the quality process and is checked regularly by each worker. Once you have finished one subassembly, the quality manager comes again and checks all the paperwork. This is the regular process. It happened in the past; there are some cases where people cheated with parts, but if this comes out to the authorities, the airline would lose its certification to transport people. So the airline itself and the customers of the MRO shops make sure that you are using new parts and full paperwork. Everybody in the line has the mindset that they need to have a 100% sound quality part. With a BMW car, when you are the customer and say, ‘I would like to get a much cheaper clutch part for my BMW,’ it is your decision to replace it with a non-genuine part. From the airline point of view, they do not want to endanger their certification to be an airline. Therefore, the customer from the first step makes sure that everyone in the line, down to the supplier and down to the factory, is using certified processes and certified parts. Otherwise, they go out of business.

Nick: I just did a quick Google and saw there are 10 or 15 coalitions of aviation supply chain integrity organizations that think about this all day. That was a really good question.

Georg: [00:21:00] I remember many years ago there was a problem with Alitalia, the Italian airline. They had included old, refurbished parts which were out of service. One of the quality managers or one of the workers—I don’t recall the whole story, but one guy in the line—found it out by accident. The whole line makes sure that nothing happens. I think from the quality point of view, we are on the safe side, but on the other side, it is very time consuming and very expensive.

Nick: [00:21:30] We only have a couple more minutes, and I wanted to ask you: you’ve recently gone into the Hyperloop business, which I assume is somewhat less regulated. I’m not sure how terrifying that is. Can you talk a little bit about some of the differences and similarities? Is it just the Wild West? What was it like?

Georg: [00:22:00] It’s really not the Wild West. There’s a big opportunity because authorities just started to create the first requirements for Hyperloop systems. All seven Hyperloop companies on the planet at the moment are sitting together with the EU authorities, trying to define the whole transportation system on a high level. This is a big chance for the Hyperloop companies because they are there from day one to define this new technology. You derive requirements from rail systems and other transportation systems, but when it goes down to specifying details about the tube, the vacuum, the linear motor, and the guidance and levitation, then you are putting in the actual developments they have. Therefore, it’s an opportunity right now to do the right thing at the right moment.

Nick: Yeah. Chris, you and I were talking about policy debt in aviation being even more scary. Do you see any backwards compatibility, where stuff happening in Hyperloop could actually get people to update aviation engine requirements? Or is it?

Georg: [00:23:00] I don’t think so, because these are two completely different books. This is the authority for transportation in the rail world or in the Hyperloop world, and has nothing to do with the FAA or with EASA for the aircraft business. These are two completely different pairs of shoes.

Nick: I want to thank you for joining us. This has been really interesting. Thank you so much for telling us all about this. This has been the Tech Debt Burndown podcast. I’m Nick Selby.

Chris: And I’m Chris Swan. Thanks for listening.

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