I’ve been following your discussions about delivery issues in the engine market and can weigh in. I placed an order for a Lycoming IO-540 Thunderbolt engine for my Van’s RV-10 project in February 2022, understanding I would have to take delivery by the end of 2022 to avoid a price increase. It was ordered through a Lycoming preferred dealer (a Lycoming salesperson even placed the order) because I wanted it with the new E-MAG ignition system—an option not offered through Van’s at the time.
To date I still don’t have the Thunderbolt engine. I have been told multiple times over the last two years that Lycoming is resetting the build schedule, there are supply chain issues and delivery is a few months out. In December of 2023 (nearly two years after I ordered the engine and a year and a half after I was told I could take delivery), I got a call from the dealer that Lycoming had a slot for several Thunderbolts that were on order with them. Finally, the engine will be in production and I should have it early in 2024. This was approaching my limit on working around not having an engine, but I would make it work. January and February go by and I heard nothing. I emailed Lycoming again and was given the same explanation as two years prior that the company is resetting the build schedule and has supply chain issues.
I am almost complete with my RV-10’s main assembly and at work stoppage without an engine.
I was given an order number and an engine serial number provided by Lycoming, but still no engine. Why do these engine builds take so long?
—Mark Welch, via email
While engine supply challenges aren’t limited to Lycoming Thunderbolts, we reached out to Lycoming to learn why it takes a few years for delivery and got a fast response.
“The Lycoming experimental Thunderbolt product is custom-built by one or two employees—start-to-finish—versus being assembled and processed with production engines, certified or non-certified. There are additional enhancements that are part of the Thunderbolt product that increase build time, such as port and polished cylinders, part balancing and custom paint.
“Lycoming has a substantial backlog of Thunderbolt orders. The backlog started to grow during the pandemic, as builders had time to pick up and/or start their kit projects, increasing demand. It also had the well-known effect of slowing down the supply chain and created labor shortages. Lycoming, like many others, was impacted by higher-than-expected orders with lower-than-required supply.
“At the same time, the market shifted towards a more high-end build. Many builders of Vans RV-10s and RV-14s elected to have the best equipment for their kits, further driving up the demand for the Thunderbolts over our traditional non-certified Lycoming engines. More than 75 percent of the orders for Thunderbolts are for the two specific engine models destined for installation in the RV-10 (YIO-540-D4A5) and RV-14 (YIO-390-EXP119); that makes the demand for those specific components even higher.
“There isn’t a particular component that causes a delay. It’s model dependent and isn’t always the same. If you use the RV-10 and RV-14 examples, the IO-540 is constrained by the casting of the magnesium sump and the IO-390 is internally constrained by output of crankshaft production. The supply of aviation-grade magnesium castings has been very challenging since the onset of the pandemic. This challenge is shared by all aviation manufacturers and is not limited to Lycoming; we’re making every available effort to try and accelerate parts supply, up to and including approving and qualifying second sources.
“Internally and across the industry, there is a significant shortage of skilled Non-destructive Inspection (NDI)/Non-destructive Testing (NDT) professionals. Lycoming is making every effort by prioritizing training of internal personnel by investing in college programs. Certified NDI inspectors require hundreds of hours of logged training.
“Lycoming forecasts engine delivery dates based on current engine backlog, component lead times, resource availability and build sequence as it is currently. These factors continuously change. Most Thunderbolt orders are placed through Vans Aircraft, accounting for more than 95 percent of open orders.
“Lycoming and Van’s had to put a pause in production of those engines after their bankruptcy petition. Van’s and Lycoming have come to an agreement on business moving forward and engines will reinitiate build starting in April 2024. Engine production for dealer orders never paused.
“If a customer is interested in ordering a Thunderbolt product, they should anticipate lead times greater than 36 months. The leadership at Lycoming Engines recognizes the situation outlined in this customer’s experience. Lycoming is doing its best to make the right decisions for the market to keep everyone flying, and continue to work to decrease lead times and reduce the backlog of orders.”
It’s worth mentioning that at press time, Welch got an update that his Thunderbolt engine was finally entering production. It’s a good lesson to other engine buyers to expect delays—long ones.
