Lycoming Requires Conrod Inspections

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Lycoming issued a Mandatory Service Bulletin on Monday that requires owners and operators of its engines to check them for connecting rods that contain bushings that do not meet Lycoming Engine’s specifications. The bushings were manufactured between specified date ranges from November 2015 to as late as February 2017. The service bulletin specifies the dates and part numbers. Lycoming said Tuesday that it didn't have an estimate of how many rods and bushings are impacted.

The SB contains a warning to owners: “You must complete the ‘Required Action’ in this Service Bulletin. If you do not complete the ‘Required Action’ in this Service Bulletin, and the connecting rod bushing moves out of place, the connecting rod can fail and cause un-commanded structural engine failure.”

The first step in the SB requires operators to check their engine serial numbers to identify affected engines. The SB applies to all engine models Lycoming makes, including factory-new and overhauled engines and, potentially, those overhauled by field shops. However, only a fraction of these have the suspect bushings. Lycoming estimates that about 1300 factory engines will require inspection, but a much smaller number will require bushing replacement.

If the engine is affected, the Lycoming parts source must be contacted to review all the engine paperwork to determine whether the engine could have one or more of the suspect connecting rod bushings or connecting rod assemblies. If the suspect parts are found, cylinders will have to be removed and the parts replaced. Lycoming is manufacturing a special tool to assist in this process. It estimates the work could take 12 hours for a four-cylinder engine and up to 20 hours for an eight-cylinder engine. The work may be covered under Lycoming's warranty, but it's unclear if field shops are expected to cover the costs of such work. 

Comments (5)

Lycoming ... YGBSM !!! I read the bulletin ... 12 hours to do this work on a four cylinder. How do you do that ... using "Fairy Dust?" If I owned one of the affected S/N engines ... I'd be suing you unless you shipped me a NEW replacement engine and paid for the R&R. If I bought a new truck and the engine had a serious issue like this ... I'd expect no less. The FAA needs to figure out what's wrong with your QC program in house.

Posted by: Larry Stencel | July 19, 2017 7:12 AM    Report this comment

I don't think that any court would require Lycoming to replace your entire engine due to it having a small defective component. A con rod bearing is a $5 part and does not justify a new $20,000+ engine replacement.
Now, regarding the labor involved, sure, they should be liable to pay for whatever time it takes, within reason. I'm not an A&P, but I know how airplane engines are put together. If we're talking about the small end bearing, (the article doesn't make that clear) I'm not sure that 12 hours is so unreasonable, since the engine doesn't even have to come out and it says that Lycoming is providing a tool to remove the bearing from the con rod.

Posted by: Jerry Zezas | July 19, 2017 7:47 AM    Report this comment

Did you read the MSB, Jerry? Have you ever taken a cylinder off of an engine ... especially something like a Mooney? I AM an A&P ...

Posted by: Larry Stencel | July 19, 2017 8:41 AM    Report this comment

AND ... as the famous mechanic Mike Busch recommends ... NEVER take off more than one cylinder of an engine at a time. This involves the connecting rod MAIN bearing, potentially, as well.

Posted by: Larry Stencel | July 19, 2017 8:43 AM    Report this comment

It's probably more than a $5 part. Even if were, John Schwaner (Sky Ranch) has a few photos in his book showing catastrophic damage from con rod failure. You can fly for a while without lubrication to your mains, but due to their small surface area, con rods fail fast. And when they fail, that flapping rod can poke a hole thru the case. I've known pilots who have flown for a while with a bad cylinder. I doubt you can make it for 30 seconds with a failed con rod bearing. I'm surprised that Lycoming isn't grounding aircraft immediately. Bad gamble. One death and it won't pay off.

Posted by: Mike P | July 23, 2017 2:56 AM    Report this comment

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