Euthanasia for aircraft engines

Mike Busch of Savvy Aviation was at Oshkosh talking about his new 500-page book. He described replacing a functional engine at TBO (usually around 2,000 hours of flight time) as “euthanizing an engine.” He points out that old age problems are less sudden and severe than new-engine problems.

For an IO-360-powered Cirrus SR20 is there a reasonable alternative to a new-in-the-box engine from Continental? Busch said good things about John Jewell in Memphis, TN and Zephyr Aircraft Engines in Florida.

What does he think about the Cirrus? He was skeptical at first about the parachute, but now “unlike the second engine that’s out there trying to kill you all the time, the CAPS system sits there quietly until you need it.”

Busch supervises maintenance for a lot of aircraft, including my dream family airplane, the original Piper Malibu with the four-blade MT Prop STC (reduces interior noise dramatically to the point that it measures as quiet inside as a Pilatus PC-12)? Based on his experience, Busch says that it is not crazy to own one and he likes the original TSIO-520 engine better than the -550 conversion that a lot of owners have done. Busch says that Continental has fixed all of the issues with this engine (maybe I’m just not following the news carefully, but I don’t hear about Malibus suffering engine failures anymore) and a Malibu operated primarily in the mid-teens should be a reliable mule. (Operating this plane right up to its 25,000′ service ceiling deprives the engine of cooling due to the prevailing thin air.)

Can it be that Busch is right and the engine manufacturers and the FAA are wrong? I know of at least one R22 that came out of the sky and into the water with a supposedly bulletproof Lycoming four-cylinder engine that was operated a few hundred hours past TBO. A friend limped to a runway on one cylinder with a 20-year-old low-powered engine that was still within the TBO hours but beyond the 12-year recommendation. Our new-in-the-box Continental engine has run more or less perfectly for 13 years and about 1950 flight hours. Why not another new-in-the-box Continental? (only $47,000 plus removal/reinstall)

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13 thoughts on “Euthanasia for aircraft engines

  1. WTF uses Continental and Lycoming ripoff engines designed by Homo Erectus anyway? Don’t they have limestone pistons and aren’t they flint ignited? Ever heard of the Rotex 912 and 915?

  2. I think it really depends on the quality of the overhaul. A very carefully overhauled engine can be BETTER than a factory new engine. A poorly overhauled one can be hit or miss. Factory new engines are not always perfect out of the box either.

  3. What are your actual choices at TBO? Is he suggesting something that is not (legally) possible, or something that has merely become unpopular? (Refurbishing existing engines)

  4. superMike: If you’re Part 91 (private business/family operation; flight school) then it is not illegal to continue operating past TBO and wait for the engine to being showing signs of wearing out, typically cylinders that need replacement. So Busch’s suggestions are both legal and practical. One guy in the Cirrus owners’ group says that he has gotten 3,400 flight hours out of this engine, albeit with a few cylinder replacements (themselves not cheap!).

    If you’re Part 135 (charter) or 121 (airline) then the local FAA FSDO may well have granted you an extension beyond TBO based on high-quality maintenance and frequent operation (which tends to enhance life). If not, though, you’re required to overhaul or replace the engine at TBO.

    The options for this particular engine are overhaul at $33,300 (independent shop; 10 weeks of downtime), factory reman exchange at $41,000 (2-7 days of downtime), or factory new at $47,000. Add $5-8,000 for the removal/reinstall and replacement of hoses and other items that make sense to replace.

    Dwight: Our flight school had to export our Rotax-powered Diamond Katanas back to Europe. Rotax was not supporting its certified powerplants and new in-the-box engines were overheating. Diamond itself abandoned Rotax (their fellow Austrians!) and installed a low-power 1950s-vintage Continental engine in the airframe (see https://www.diamondaircraft.com/aircraft/da20/ ). The performance of Rotax-powered airplanes is not dramatically superior to the performance of similar-size airplanes powered by 1950s Continental engines.

  5. Jackie: So true! We’ve had multiple cylinder failures on Lycoming factory reman engines that we recently installed in our Robinson R44 helicopters. I guess they are running out of old guys to run the precision machines.

  6. It’s interesting: you can buy an entire Mercedes (not a fancy one) brand-new for less than that!

  7. superMike: Even more painful is looking at the price of adding air conditioning to a light airplane. It will cost more than a new Honda minivan and won’t work nearly as well or as reliably as the air conditioner included in the minivan.

  8. “blame the lawyers” is a good go-to here in the U.S., but it turns out that the health care industry was lying about that (see https://www.forbes.com/sites/rickungar/2010/09/07/the-true-cost-of-medical-malpractice-it-may-surprise-you/#1d724f232ff5 for how at most medical malpractice accounts for 2.4 percent of health care costs, mostly on defensive tests)

    I’m not sure “blame the lawyers” works in aviation. Liability exposure is greatly reduced in the experimental world and engines for homebuilt airplanes aren’t cheap, either. A four-cylinder starts at about $25,000 (see http://www.aircraftspruce.com/catalog/eppages/superiorxp.php ). I don’t think that this is much more than the OEMs are paying for a new four-cylinder Lycoming.

    Also, I don’t think those aftermarket rebuilders are carrying a huge amount of insurance. What assets do they have to protect? I think the issue is that these engines are being hand-built in a country where labor is super expensive.

  9. I recommend you read Mike’s work. His old columns on Avweb, now sadly hard to find if you don’t know to look for them, are a real eye-opener to anyone maintaining a piston airplane.

    https://www.avweb.com/news/savvyaviator/

    He’s a huge proponent of on-condition maintenance. That requires being aware of condition. He more or less requires an oil analysis from Blackstone at every oil change on planes he manages. He demands borescoping cylinders at every annual. He highly recommends an engine monitor with exportable data, that his software platform can analyze for signs of sticking valves, clogged injectors, etc.

    He doesn’t just say run your engine until it quits. He says to listen to what your engine is telling you.

  10. Thanks, Joshua. I have downloaded his latest book (now referenced above) in Kindle format. Unfortunately I don’t think it will work well on my phone. It seems to be a PDF, essentially, rather than the usual Kindle format in which text size adjusts to screen dimensions. Our SR20 does have an engine monitor and the East Coast Aero Club mechanics who maintain it do look at the data, but I will have to dig in more to see what they’re doing. They more or less share Busch’s philosophy of waiting for a sign from the engine that it is ready to depart this life.

  11. Airline turbine engines don’t have a TBO, but they do have crucial parts that are life-limited by cycles (takeoff power to shutdown). This usually brings them off wing after two to five years (domestic vs. international), for a refurb that shuffles the parts to optimize the remaining life. The shafts and cases stay together as a serial-number unit, but the rotating parts and accessories live or die by inspection/repair unless they are cycle limited. A lot of health monitoring goes on to catch bearing failures and vibration, plus borescope inspections of blades and vanes (static foils between rotors) for cracks and deformation. Engine maintenance is very complex and expensive but the result is most pilots never experience a failure or in-flight shutdown. Engines are purchased and managed separately from airframes, and cost $millions ($24 million each on B-777).

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