Lycoming Connecting Rod Bushing AD 2024-21-02

[MikeOH]

Just got this email notification:
https://drs.faa.gov/browse/excelExternalWindow/FR-ADFRAWD-2024-25365-0000000000.0001?modalOpened=true

Looks like mandatory oil sampling for metal (bronze) is required starting on 12/5/24 for nearly all Lycoming engines with the suspect bushing and shipped in a date range roughly from 1/30/2007 to 2/14/17.

That's my read of it, others chime in if that's not accurate.

Many of us probably aren't affected as that date range is well past when our engines were last apart!

Pretty good news for Blackstone Labs, I would think

[haymak3r]

lol. you BARELY beat me. I will remove my thread..

[EricJ]

I don't see a requirement for spectrographic analysis, just a visual inspection of the filter media for bronze particles.

[AndreiC]

Well, my engine was overhauled in 2012, and in talking to Penn Yan (the overhauler) it seems that it might have the affected bushings. I will ask Penn Yan if visual inspection of the filter is enough or if I need to send the oil off. 

Do any of you guys know if these bushings would be replaced when cylinders are replaced? I got all new cylinders in 2021 (so past the affected dates), but I see no mention of any bushings being replaced.

[MikeOH]

Hmm, based on @EricJ's comment this is looking like a 'nothing burger'...doesn't everyone look for metal particles when performing an oil change?  This is starting to seem like a pretty silly AD.

[AndreiC]

After having read both the AD text and the Lycoming service bulletin it refers to, I am quite a bit more confused. Lycoming says that one has to inspect the rod bushings and worry about them if at least 6 bronze "chips" are found in the oil filter or suction screen, or at least 3 bronze chips and 3 aluminum chips are found (in which case one has to inspect the pistons as well).

However, the AD text refers to the case when "any bronze metal particulates are found and the source is identified as the connecting rod bushings". According to Lycoming there is a significant distinction between bronze chips (less than 3/16" but larger than 1/16) and small dust-like pieces (smaller than 1/16").

What are we supposed to do if we find a few bronze dust-like pieces? Inspect the bushings or not?

[N201MKTurbo]

Sounds like CYA to me. 

When I rebuilt me engine, I sent the rods to Aircraft Specialty Services, who replaced the bushings. Does the AD affect them or just rods rebuilt from Lycoming? Or was it any engine that used Lycoming bushings? I would have to dig into the paperwork to see if they told me which bushings were installed.

[EricJ]

12 minutes ago, N201MKTurbo said:

Sounds like CYA to me. 

When I rebuilt me engine, I sent the rods to Aircraft Specialty Services, who replaced the bushings. Does the AD affect them or just rods rebuilt from Lycoming? Or was it any engine that used Lycoming bushings? I would have to dig into the paperwork to see if they told me which bushings were installed.

Yeah, it's not straightforward.   My engine was originally built well outside the covered date ranges, but got an IRAN in 2015.    I looked up the IRAN record and none of the affected parts were on the part list, and there was no indication that the bushings were touched.   Seems like an NA to me.