title: 204. The Clock Is Ticking on 7FA Gas Turbine Rotors
author: The POWER Podcast
contenttype: podcast
publication: The POWER Podcast
published: 2026-01-29T00:00:00
sourceurl: http://dts.podtrac.com/redirect.mp3/feeds.soundcloud.com/stream/2251394690-user-755104578-204-7fa-gas-turbine-rotors.mp3
word_count: 4670
Hi, everyone. This is Aaron Larson, executive editor of Power Magazine, and you are listening to the Power Podcast. On today's episode, I'm joined by Dave Fernandez, Jason Wheeler, and Spencer Hamilton. All three are with MDNA, and I'll let you each tell a little bit about yourselves and what you do with the company. So Dave, why don't we start with you. Thanks for joining me. Thanks for having us, Aaron. So I've been in the power industry since I graduated from mass merit time back in 1996, and I started off in the industry with GE, and just so happens that my focus with GE was on the gas turbines and in the time frame that actually the line's right up with this topic. I was, I was a GE field engineer servicing the frame seven and frame nine fleets through the world as a start up in DLN, a specialist from 1996 through 2001. So I saw a big part of the bubble that we're going to be talking about here in a little bit. And for about a decade, I ran power plants, and then I came back to MDNA and ran large outage service projects, ran manufacturing for a good chunk of time, and then came over and took over the gas turbine rotors program about two and a half years ago. So it kind of come full circle. Sounds like a great background for what we're going to be talking about, and we'll get into that in a moment. But Jason, why don't you tell a little bit about yourself and what you do with MDNA? My background is a little different than most in power generation. It seems like I am a military person by trade, I guess. I left the military back in 2008 and fell into conversations with MDNA in 2013, and I've been with them ever since. I started off in the valve stop in St. Louis with MDNA, and I ran that shop for about eight years. And now for the past five plus years, I've been running the gas turbine road repair shop in St. Louis. It's a very large shop with lots of resources, and it's a fun place to work, and a fun group of people to be with, and obviously the work is very interesting and fun as well. All right. Thank you. And Spencer, last but not least, why don't you tell us what you do as the gas turbine services sales director? Yeah. So I'm responsible for the overall turn key offerings that MDNA brings to the market. The gas turbines bring along some of our legacy products, a steam turbine and generator to, yeah, again, give that turn key solution to our customer. My background is a field engineer with a OEM on gas turbines. I've worked for a different, a couple of different service providers over the years, been in the industry for going on 15 years now. Great to have you. And obviously Dave kind of mentioned the fact that we're going to be talking about the seven F A and some of the things that have happened over the years back in the early 2000s, the gas turbine market was kind of in a boom. Can you talk a little bit more about that and how that developed? Yeah. So back in the really started in the late 90s, deregulation came into play and there was a rush to the quick build power plants, which were simple cycle, combined cycle gas turbines and the G7 F A and 70 A, both of those were very popular units at that time. A lot of people will remember and Ron being a big part of that and how they helped drive that and then helped to end it to some extent as well. But that's essentially what the bubble was. It was a rush to market by a lot of independent power producers and some and some utilities with quick to market power generation assets, which were gas turbine based. And what did that mean for GE? I mean, they sold and installed a lot of turbines at the time. Yeah, it was quite a challenge for them and other OEMs at the time to be able to scale up from a production standpoint to support the demand GE, and particularly if I recall correctly through international partnerships and expansions at their own facility, they more than doubled their annual capacity for producing gas turbines during that period of the bubble. If we fast forward to today, a lot of these turbines are now 25 to 30 years old. What does that mean for their remaining life and why is it important for companies that are operating these turbines to start looking at that and planning for the future? Well, the OEMs have set certain components in the road themselves have life limiting factors, implement them on them. You can run beyond those factors if you choose to, but there's a huge risk to do so. And that's why those limitations have been placed. Not planning for those hours and the completion of those hours will lead customers in a hole, so to speak, if they don't plan early. And what are some of the the biggest risks that they face if they're not planning and thinking about the extending the life of these rotors? The biggest thing in my mind is going to be component availability. So even now, we're at the very front of this bubble, right? And there's issues with trying to find components and vendors that can manufacture these components and the lead time that it takes to manufacture these components. It's not like a steam turbine where you lose a major component and there's, you know, 20 different vendors that you can talk to and come up with parts and you might have blades or whatever in 12 or 14 weeks. That's not going to happen if you need a 7FA.03 T1 turbine wheel. If no one has, when you're going to be waiting years and then what's your backup plan there? So if you don't plan for it, you're going to be the one stuck in a hole and you don't want to be that company. Maybe one thing to add there is maybe also not having the opportunity to understand exactly what the given customer needs. I don't think every customer needs a full blown new rotor. Maybe they can get away with something else. But if you're reacting to coming up on the time clock, the only option would be a new rotor. So the more advanced notice, the more time they have to do their homework and see what options are out there. Yeah, it's always better to plan for something than to have it forced down your throat at the end when you weren't expecting something. Things are going to change regardless, but if you don't start with a plan, you're never going to get anywhere. So what role do these aging assets currently play in our overall energy mix and how critical are they to the grid reliability? Yeah, so we're seeing the 7FA as well as the EA's predominantly, you know, base loaded units, especially with this boom in AI and in the assets that are not being used or even seen in moved areas where they can be utilized. So I would say they're critical, especially with a demand of new units. Only so many can be made in that lead time being long. So these assets are being ran longer and more than I think might have initially been expected. What are some of the most common damage mechanisms that you see in these aging E and F class rotors? So it's about like on the compressor side, right? The the aft end of the compressor, you get cracking in the dovetails. So there's some enhancements that have been made by the OEMs and us as well with the geometry of those dovetails. So there's some known upgrades for known issues, but then there's also unknown issues if you've had events in the past, right? Everything adds up to whether the rotor components will have life in them or not. If you've had a lot more stars versus base load and run time, if you don't have clean air going into your compressor and you have oxidation and corrosion issues. And then the the four strategies and racks, but that's not typically tied to and the life unless you're just running well beyond what you're supposed to and something bad happens. You want to catch it before something bad happens or it's a much bigger issue. And especially in the super alloys in the in the Ingloy based wheels, it's a very robust super alloy that that holds up well in high temperature conditions. The downside of it is when there's a crack initiation, which which in this case is a fallout from a low cycle fatigue, pre does it really come in with the temperatures it seems, but low cycle fatigue is is the concern in these and there's microcracking that takes place after so many cycles. And that's what the limitations are based on. The OEM limitations are based on when they they forecast that those microcracks to start taking place. When those microcracks themselves are in a problem, but when they start connecting, that's when you get you can get into some problems and quickly on the super alloys. And so they're a robust material. They're great for the environment, which that they operate in, but when they crack, they oxidize and crack propagation is accelerates and these super alloys more so than on the other compressor side, which is chromoly D and doesn't see the same crack propagation rate that the super alloy does. Interesting. So are are all of the seven FA rotors the same or are there design or manufacturing differences within the fleet? So there are some some differences, right? For me, with the the tear down or on-second restack, there's some minor geometric differences from some rotors one to the next. The larger picture, the larger question I believe you're asking, there are some differences in the way that some rotors have been designed. There's some different things that some companies are doing that others are and there's some enhancements out there that that are available like from all ABF shafts, right? So there's there are some differences within the turbine sections that you'll come across, there's some geometric geometry differences on the on the rotor as a whole, but generally they're they're thought to be interchangeable, right? So plug and play, but there are some differences. And then there's some evolutionary differences that Jason alluded to one earlier, but you know, there's just like with any product line, there's there's lessons learned and the lessons learned lead to enhancements and upgrades. So the there's there's quite a few enhancements and upgrades that have taken place on the seven FA over time. The one that Jason had alluded to is the back end of the compressor had flat slot bottoms. Most people that run these assets, you know, that the flat slot bottoms when they open the unit up and they inspect them, they're going to have cracking on the trailing edges. So one of the enhancements that came from the OEM that's that we also deploy is the round slot bottoms. There's other enhancements on the turbine side of the coupling that also have enhancements to mitigate cracking that would take place in the cooling slots on the balance wheel. So there's differences there. There's there's a limited number of options in terms of who can manufacture and provide these the super alloy components that go into a relative extension. And the differences you'll see there is the OEM and it is well as MDNA deployed the same super alloy. We deploy the same super alloy because the more expensive options that are used and like the H machine aren't necessary because the material in the H machine, for instance, is an ANCO-718. ANCO-718 is necessary when you get into the creep conditions. You don't get into creep conditions on the seven FA. So it's a more expensive material that guards against creep, but it's not necessary on the seven FA. It just increases your costs. The value it provides is it required so you're not getting what you pay for. So there are differences when you go from one solution to another, but at this point for the most part, the geometries for the different components you'll see and product offerings have all taken into account upgrades and enhancements to guard against issues that have been seen from a crack initiation risk mitigation standpoint. And we talked a little bit about the fact that demand in the electric industry is increasing rapidly and that's impacting manufacturing and other things in the industry. There's outage constraints to think about. There's other items. Why should customers be thinking about their rotors now or for the next three to five years? What's the urgency behind this? Like we were kind of talking about earlier, the demand on the energy's causing capacity constraints, right? I think the big thing why to think about it now is for a customer can have options not be forced down a route. I know I would want options when I'm looking for a new car. I think customers should have that option as well. What about supply chains in the delays or the lead times that are required for some of these components to those factor in as well? Very much so. There's not a lot of different vendors in the world that actually produce these components, right? They're very specialized materials that are specialized process to produce and whether it's the forging themselves or the machining aspects. So if you're not if you're not thinking two to three years down the road on your rotor, then you're already behind because that's how long it's going to take to manufacture those wheels, right? So MDNAs poised in a good spot to have those wheels on hand in St. Louis, but there's not an unlimited amount in St. Louis and there's not an unlimited amount in the world. So unless you want to get left behind, you're going to have to plan, you're going to have to plan early. It's not like on the steam side where one says plan six months to a year out, you're going to need to be two to five years out planning. If you want to be set up for success. The other thing that commands that is the other industries, with the other industries are booming right now. The forging house is all supported because it's the multiple industries. So you got the arrow, you got the power generation boom that's happening right now that's that's consuming a lot of the forging houses lead times and then you have military. So all three of those have large orders in place right now for new. So now we're talking about competing with those new unit sales across various industries and attempts to I guess get in line and with what was is perceived from some angles as higher priorities with replacement wheels for aging assets. So it further complicates the scenario that the industry is facing, that the customer base is facing when they're trying to extend the motor life of their existing assets, which is becoming again more important now because of the power surge we're seeing and the forecast we're seeing that is based on the server demands and the current and future. So I think there's a lot we went to a bubble before. I lived through the bubble before. There seems to be a lot more concrete reasons and a much stronger foundation for this current bubble than the previous one that took place two and a half decades ago. There's a lot of things that are all stacking up at the same time that put some more of an emphasis on getting out in front of extending the life of your current assets. Now probably more than ever in the time that I've been exposed to the power industry. Have you seen that reflected in prices as well? Have the costs for these components gone up significantly due to the supply constraints? Absolutely. And we should expect them to continue to go up. Additional complications come into play currently too with tariffs, but those are unpredictable right now. They come and go, but supply and demand has forever been a part of every industry, right? And the demand is high and the supply is squeezed right now. So we should all expect the price tag to increase. Going a little bit more into the the rotors and the life extensions. At what point does a rotor become a run to failure risk versus a viable life extension candidate? And are there indicators that owners should be watching for? The first thing is once you go through one life extension, right? You're typically not going to go through another. So once you go through the first one, you're going to have to start looking to need to purchasing a new rotor, way down the road or run into failure. I personally would not say any rotor would be run to failure. I would say take it apart, look at it, investigate and inspect it and figure out what the issues are. And then it doesn't have to be a run to failure. There's going to be some instances where maybe the whole rotor might be a fallout or scrap deal, but those are going to be way few and far between. I mean, we can we can repair a lot of stuff. And NDNA has the capability to produce lots of parts. And we have lots of very expensive capital parts on hand. So my personal opinion is to never say that a rotor is run to failure and tell you absolutely know it. And I don't know that I've ever necessarily come across one that I would say, yep, there's nothing you can do. Run to tell it dot. I think it's as this is as simple as adhering to the limitations put in place. Because once you get to a rotor life extension trigger or a rotor end of life trigger, I should say, based on the OEM's guidance and then based on the guidance that you've been by the service entity that extends the life of your rotor, if you go through the very detailed rotor life analysis that comes along with that program, you're going to know whether or not your assets are at risk shot, the ultrasonic testing, the eddy current testing, the dipenitrant testing, the material analysis, you're going to know whether or not you've had property changes that put you at risk with the rotor life analysis programs in or in place. I originally the 70A was never meant to go through more than one rotor life extension, but now you have 70As out there that are that have been it's been extended twice. We're not there yet on the 7FA. So before anybody can say the 7FA can be extended a second time, the fleet leader needs to get there. Some destructive testing probably needs to take place on on multiple components and then a determination can be made. The most likely scenario is they will also be able to be extended, but the number of components that will have to be replaced will be expanded beyond what the current standards are. So that's adjacent point. I don't think you'll ever have to as long as you adhere to the limit like limitations put in place and you have your predictive maintenance rigor and your preventive maintenance rigor and you going through the in depth of rotor life analysis, you should really shouldn't be at risk of running one of these assets to failure. You should never risk that. From the personnel safety standpoint, you should never flirt with that, right? Just starting and ending right there, you should never even consider that an option. From an operational standpoint, how do unplanned rotor issues typically show up? Are there performance degradation indications or vibration? Do you find it in inspections or forced outages? What do you typically see that happens first in these things? Change is every time. A lot of them just show up simultaneously, right? But one of the failure mechanisms has been stage bolting. T1 stage bolting. You have a T1 stage bolting issue where you have a failed bolting assembly. It's going to show up in your vibration profile, right? But if you have micro cracking taking place in your cooling hold geometry and your turbine wheel or on your lock wire tab, you're only going to find that during inspection and through a dipenitor to the micro structure cracking that then initiates on the turbine wheel. You're not even going to find that with a boroscope. There's cracking you can only find through a rotor life analysis. Then there's other cracking that you're going to find that Jason alluded to earlier on a flat slot bottom wheel that you may be able to you may be able to see that with a boroscope. But there's different elements that you're going to have to go through the whole rigor of predictive preventive maintenance in order to ensure that you're guarded against it all. So vibrational ticket up and sometimes performance decays slowly over time. The only time your performance is going to probably be an indicator is when something else goes with it. Like if you have foreign object damage in your compressor, it's going to just going to show up probably in your vibration profile and you perform it. You're going to find some things with boroscope inspections and some things you're only going to find through the detailed analysis that's done neuro rotor life analysis. How have inspection techniques evolved since these rotors were first installed? Have you seen big changes in technology that allow you to see and find problems more easily today? I believe on the NDE side, there's certainly been some growth there. On that specialized NDE, we use a vendor that we partnered with. So luckily for us in those aspects, we haven't had to make those RAD investments or growth within MDNA. But there's an industry leading vendor that we have partnered with that does our end-of-life NDE section of that inspection that has some very high-tech inspection methodologies, volumetric phased array where you can basically fly through the part and look for imperfections. That was a new one for me. There's just lots of neat inspections that they have the capability to do that you don't see anywhere else like in, let's say, the steam world down at the other end of the shop. I think a lot of the inspection methods have been in place for a while, like the phased array, but they've just been enhanced, particularly on the software side from the analysis side. The tooling, but the technology itself, the geometry of the tooling. So it's definitely enabled more thorough inspections over time. I don't know if there's new technologies that's been involved, but the technology that's been in place has been evolved to provide more thorough inspections of honestly all-power kind equipment, not just the roaders. Lots of our internal methodology there in the shop is centered around safety enhancements. From the first time we took a road or a part till now, we've overturned a lot of our tooling and made it better, more ergonomic and more safe for the people you use. I can say where there's been significant enhancements is on the R&D side. Much more precise methods have come into the marketplace over the last couple of decades to enable more precise, accurate, reverse engineering methods. One example is blue light scanning. That's been evolved and improved on, and it's a very tightly tolerance method for reverse engineering. In what's one thing that you see owners misunderstanding when it comes to road or life extension? Some of our customers don't understand the aspects of what it takes to do the inspection and the timing and the cost. The known plan are known plan may be different than the OEMs, known plan and the differences there. When somebody is dealing with one vendor versus another, there's just going to be some differences. I think one thing they don't understand is what I was alluding to earlier. If you make certain decisions in terms of your road or life extensions, there's upgrades you can perform along the way. That'll get you performance improvements and more capacity is a popular thing, right? More a higher performing unit with more outputs important. Customers should go in, should get educated and understand what sacrifices they're making, and it was what I was alluding to earlier. If you make certain choices in terms of what you do during a road or life extension, you may pigeonhole yourself to a single source provider, which inevitably is going to create lead time and schedule impact problems. When you have one solution available to you more often than not, you're going to find yourself between a rock and a hard place. No one wants one solution. It's just not a good place to be. So understanding what puts you in that scenario is probably the most common misunderstanding or missed contemplation that I come across in the customer space. If there was one piece of advice that you could give to an operator who's managing a 20-year-old gas turbine today, what would that be? Pick up the phone and start a conversation. Nobody knows everything. You don't know, you don't know. Operators know how to run their units. They don't know necessarily the fleet-wide problems or have the experience of a shop seeing 20 roaders go through the shop at once. Pick up the phone and have a conversation. I mean, say that to everybody, right? That's the start to anything. So learn what you don't know. Get educated on what's there and what's not there so you plan for the future. And then go from there, right? Make those decisions and act on. Yeah, just to tie into what Jason said, I was going to say, get educated. Take the opportunity to visit multiple vendors. Go look at their shops. Ask the tough questions. Yeah, get educated. My suggestion ties right into that, actually. Understand what your decisions do from an optionality standpoint. There are certain decisions the customers can make that will tie them to one solution, which is the OEM. And the OEM is very focused right now on new unit sales, understandably as it should be. But if you make certain decisions and you're not aware of the intellectual property constraints that that ties you to, you're going to have a single option solution. So what Spencer said, I'd say, get educated, but get educated on what is going to limit your options. Because if you limit your options to one single source right now, you probably are going to be in a tough spot. All right. Well, thank you, gentlemen. Again, for listeners, I've been speaking with Dave Fernandez, MDNA's guest, turbine program manager, Jason Wheeler, MDNA's guest, turbine rotor repairs general manager and Spencer Hamilton, MDNA's guest, turbine services sales director. So thank you all for joining me. Is there any last words or anything that we haven't talked about that you think would be important to mention before we wrap this up? No, I'll just thank you for the opportunity to speak with you. Thanks, Aaron. Thank you, Aaron.