PT20J

The NTSB involvement probably didn't have anything to do with the pilot's statement. The NTSB investigates accidents which definition includes substantial damage. Note that the report lists the aircraft damage as substantial. A similar occurrence happened in June 2022 (Accident number ERA22LA319) where a M20J landed gear up in Charleston, SC due to a broken torsion spring in a Plessey actuator. The damage was classified as substantial because it ground through a structural tube in the belly much like this accident. The report picture of the damaged tube has the caption: "View depicting the damage to a tubular steel truss primary structure which required major repair and classification as an accident."

I received confirmation from Lycoming that an engine assembled by Lycoming that contains an affected connecting rod assembly is only subject to the AD if the engine ship date falls within the connecting rod assembly date range listed in the AD. Ship dates for Lycoming assembled engines can be found here https://www.lycoming.com/core-history-search This, of course, doesn't help with engines assembled outside Lycoming. That will require some research and hopefully the assembler saved the packing slips for the parts with the ship dates. My Lycoming field rep sent me the attached letter. Response to Inquiry - AD 2024-10-02_FINAL.pdf

As @kortopates pointed out above, if you push on the pins with the door open but the handle in the locked position, some will spring open with little force. Some I have checked take a lot of pressure. So, there is variation between airplanes and the mechanism has no adjustments. There is a spring the holds the pins either closed or open depending on the position of the handle and perhaps some springs are weak. It's also good to lube the piano hinge occasionally. Otherwise it will wear and be more likely to fail if the door does somehow open in flight.

The way I read the new AD is that Lycoming came to realize that the non-conforming bushings were used in additional connecting rod part numbers not listed in the original AD. I don't know what made them non-conforming. It seems likely that they were undersize because they are press fit and the issue is that they come loose. Lycoming did release a new bushing design subsequently, but I doubt that has anything to due with this problem. The description of the new bushings reads more like a manufacturing process improvement since they don't need burnishing.

MSB 632B referenced in the first (2017) AD describes the bushings as non-conforming and implies that some bushings were of incorrect diameter.

And that’s another issue. On later airplanes, Mooney took to pop riveting the panels that don’t require frequent removal for access to, and lubrication of, components. A lot of the Avex countersunk pop rivets are smoking and will have to be replaced. So, I might as well bite the bullet and just replace all the questionable solid ones and be sure. I’m kind of surprised there are so many. I didn’t count them, but there must be about 20 total. Maybe these were bucked on a Friday.

Perhaps it hasn’t occurred to you that the rest of us don’t care.

The original paint is flaking off my 1994 M20J. I'm going to get it painted this spring. During the annual inspection we noted some rivets on the bottom of the wings are loosening and starting to "smoke." I will replace the worst ones, of course, but I wonder if anyone has had luck rebucking rivets that are just starting to smoke.

I checked with Honeywell. The1CH116-6 is an obsolete part. The 1CH1-6 is available and essentially the same. Both are DPDT switches. The main difference seems to be that on the 1CH116-6, the one circuit must make slightly before the other and the 1CH1-6 does not have this feature. Presumably, this was to make sure the motor shut down before the gear light comes on. But the amount of travel is so small that I cannot imagine it matters especially since the actuator will have a bit of overrun. 1ch1-6_i.1.17.pdf

AD 88-25-11 Applicability: Models M20J (Serial Numbers 24-0084, 24-0378 through 24-1645, and 24-3000 through 24-3056) and M20K (Serial Numbers 25-0001 through 25-1160) certificated in any category. Comply SBM20-239A

My 1994 M20J has strobes only; no beacon. But it has three: one on each wingtip and one on the tail. I assume that the tail beacon was necessary to meet the field of coverage requirement.

That letter is 7 years old .

Interesting comment to FAA from Mike Busch included in the Docket for the original 2017 AD: FAA-2017-0788-0017_attachment_1.pdf EDIT: Link to AOPA letter Mike referenced in the above comment. https://download.aopa.org/advocacy/0803_MSB_letter.pdf

I agree with your analysis. But, since the 2017 AD was issued, Lycoming has determined that physical inspection of the bushing(s) can be replaced by inspection of the filter and suction screen. It is difficult to determine what parts are in a field overhauled engine from the “ship date” effectivity used in both ADs. So, it would seem reasonable for the new AD to “supersede” to 2017 AD. Unfortunately, no one made that point when the NPRM was issued (how many of us even knew about it?), and now that it is a final rule, the FAA isn’t likely to want to change it. But, I wonder if the FAA might accept the new AD as an alternate means of compliance with the 2017 AD?

It was explained in the excerpt from the Docket I posted earlier.

The o-ring is the seal. They are designed to be replaceable.

I was referring to the new AD. The 2017 AD should have been complied with by now.

You can't double up o-rings. The o-ring on these valves seals against the underside of the wing. You need to figure out what's causing the leak. Make sure the o-ring is not damaged and there is no damage to the area where the o-ring seats. The valves need to be tightened snug but not overtightened, You could try putting some fuel lube (EZ-Turn) on the o-ring before assembly.

The AD does not require any tearing apart of engines. It simply requires inspection of the filter element and suction screen at routine oil changes. The only time you need to remove cylinders is if you find bronze chips.

So, what did the FSDO say when you called them?

From the FAA Docket FAA-2024-1695 https://www.regulations.gov/document/FAA-2024-1695-0001 Background The FAA received five reports of uncontained engine failures and IFSDs due to failed connecting rods on various models of Lycoming reciprocating engines that were overhauled or repaired using any replacement part listed in Table 2 of Lycoming Mandatory Service Bulletin (MSB) No. 632B, dated August 4, 2017 (MSB 632B), which was shipped from Lycoming during the dates listed in Table 2 of MSB 632B. As a result, the FAA issued AD 2017-16-11, Amendment 39-18988 (82 FR 37296, August 10, 2017) (AD 2017-16-11), which required an inspection of connecting rods and replacement of affected connecting rod small end bushings. Since the FAA issued AD 2017-16-11, a manufacturer investigation determined that affected connecting rod small end bushings may be installed on additional populations of Lycoming engines. The manufacturer also determined that degradation of the connecting rod small end bushings is detectable during oil change inspections. This condition, if not corrected, could result in connecting rod failure with consequent uncontained engine failure, total engine power loss, IFSD, and possible loss of the airplane. https://www.lycoming.com/sites/default/files/attachments/SB632B%20Connecting%20Rod%20Identification.pdf

Sorry, I didn’t look at the other switch.

Very nice! I’m curious about the process to get the data plate replaced. We had to do that on the museum DC-3 because we discovered that Douglas got the serial number wrong when they converted it from a C-47 to a DC-3 after the war. We had all the documentation, but Boeing didn’t want to deal with it. We finally got it done, but it took two years and some personal contacts within Boeing.

This issue has been known to Lycoming for some time. The latest "ship date" listed in the AD (I'm still not 100% clear if these dates only apply to entire engines or also to the connecting rod assemblies) is Feb 2017. The Lycoming SB 480F Oil Servicing, Metallic Solids Identification After Oil Servicing, and Associated Corrective Action was updated 5/25/17. Lycoming SB 630A Connecting Rod Bushing Inspection After Cylinder Removal was updated 6/17/17. Evidently the bushings can loosen in service and either rotate in the rod or move out of the rod bore. Either movement can apparently cause them to wear and eventually fail. But apparently there have been some catastrophic failures leading to the AD. Based on the AD language, Lycoming and the FAA seem to believe that normal interval inspections of the filter media and suction screen will indicate an issue before it causes a failure. So, it begs the question: Where the filters in the engines that failed not being inspected?

I missed that. It sounds like the AD is written from the perspective of engines assembled at the Lycoming factory and the ship date applies to the date the engine left the factory. If it was field overhauled then I'm not sure how you would determine if your engine is affected.