Over on Supercub they are talking about Cirrus grounding because of counter weight snap ring problem or ??????. Curious just what is going on. Thanks

Expect SB/AD soon. More to follow. Essentially everything made from 2021 till today will affected

See below. Basically the counterweights may or may not have the snap rings installed backwards on engines built after June 1, 2021.

One side is chamfered, one is not. Counterweight departure is possible if these are installed backwards.

The aft two cylinders will have to come off to gain access to these.

Thank you!!!!! That makes sense now.

fun

It really sucks. I have 10 hours on my New 550.

"Continental engines with over 200 hours may continue flight operations" ??
I guess they figure if it hasn't come apart by now, it's good to go?

That’s what I’m assuming

hotrod180 wrote:"Continental engines with over 200 hours may continue flight operations" ??
I guess they figure if it hasn't come apart by now, it's good to go?

That's not very confidence inspiring. In my experience, things that aren't right can go sideways now or later, and even a lot later. I can't stand knowing that there is potential for serious havoc lurking within my equipment.

I once built up a motorcycle engine, got it fully assembled one night, and the next day I couldn't remember for certain if I had installed the circlips in the wrist pins. Circumstances led to having several extras on my work bench, so I had no real way to correlate quantity on hand to quantity installed. I couldn't convince myself that I didn't accidentally leave one or more out. The idea of ruining my fresh engine with these potential issues got the best of me, so I tore it back down to find everything in perfect order.

If I had an affected engine I would never have fun flying until I was certain, 200 hours or not. Sorry for anyone who is affected by this. The good news that removing two cylinders to check it out isn't too bad of a job.

A counterweight coming loose in your engine is SERIOUS business.

I can’t imagine the tense surgery of trying to change the clips through the cylinder holes.

“Ploop”. The sound of the clip dropping into the case.

Ploop, followed by a very loud MOTHER F….!,

Hopefully it all works out.

I was fueling up an R1340 powered plane and watched the engine come to a stop in one revolution, shook the wings pretty good. Turns out a counterweight had slung off and got in a bind somewhere, locked up the engine immediately, the prop wouldn’t move more than an inch at the blade tip. I’m surprised they’d even give you another 5 hours to move the plane to a maintenance facility, after watching that happen I wouldn’t crank the engine again until it’s been inspected.

CenterHillAg wrote:I was fueling up an R1340 powered plane and watched the engine come to a stop in one revolution, shook the wings pretty good. Turns out a counterweight had slung off and got in a bind somewhere, locked up the engine immediately, the prop wouldn’t move more than an inch at the blade tip. I’m surprised they’d even give you another 5 hours to move the plane to a maintenance facility, after watching that happen I wouldn’t crank the engine again until it’s been inspected.

I guess the good news would be there is less drag when the prop is fully stopped if your gliding, so there is that.

Removing the two cylinders is for the inspection. Correcting the problem on the bad engines may require more surgery.

I can’t imagine the tense surgery of trying to change the clips through the cylinder holes.

I have a old 470A crank that still has the counter weights installed. I was playing around with it yesterday and found the clips rotate freely in the groove so have an idea that might work. Rotate so the two holes are straight up, then make a tool with a rod inside a tube that can be squeezed----sorta like a hydraulic cylinder. The tip of the rod would have one 90 degree snap ring tip and the tube would have another solidly attached. Go in straight from the side and engage the holes and squeeze to shrink the ring and pull out. Do the opposite to install.Stuff some kind of flexible shelf out of paper or ???? under the crank to catch the ring if it drops off while you're practicing the first few times. For all I know a tool like I described might already exist but I haven't seen one. Some sort of inspection camera would be nice to see what you're doing too.

A tool like that might be called a magnet

Wow. I have never, and I mean never installed a snap ring without it popping off the pliers a couple times before getting it seated. Maybe I need better pliers but man what a screw up by QC…

Maybe someone can post an inspection pic once performed? I’m super curious as to the condition of the effort required.

As I read the letter from Conti, I think AftCG has it correct. The jugs come off for inspection purposes; resolution, if required is far more invasive.

That is what towels/catch devices are for.

Here’s a picture of a counterweight being removed with the cylinder and connecting rod removed.