I believe a total of 23 IO540 cranks snapped, out of thousands and thousands sold. Given that engines spontaneously croak for any number of other reasons, the likelihood of a crank failure is one that some owners would have probably accepted.
The court cases from those who had snapped cranks indicate you're wrong about that. And even still, let's say that you as a customer accepted that risk, signed an affidavit as such, and then decided to sell the plane. Now what? You sell the plane to someone who doesn't sign the affidavit, busts a crank, and then sues Lycoming.
I'd also argue that you would see more cranks fail with continued use. Part of the reason it was a relatively low percentage was because the cranks weren't in service that long.
We, the customers, demanded this level of caution in the form of repeated lawsuits, again and again.
Those cranks were a liability to the company. The people who put a value on the companies stock dont like liabilities they can't put their fingers on. By putting a fixed timeline on when the cranks have to be removed, the company could put a more or less firm end to the liability exposure.
You've also got the insurance company who paid a very large sum out as a result of this claim, and was basing their premiums on trying to recoup that money and also being wary of the future. Since Lycoming is part of Textron (and a small part at that), its individual contribution to Textron stock is relatively small.
Conti IO550s and TSIO520s had cranks snap off at the prop flange, mostly in aircraft known to be flown at high power settings (converted Malibus, Lancair etc.). It seems to me that once we hit 310hp, we start to get to the limits of what the flat-six hardware can do.
From a crankshaft perspective, history disagrees here. The TIO-540-J2BD (350 HP Navajo Chieftain engine) and GTSIO-520 (375 HP Cessna 421 engine) both didn't have crank issues regularly. The J2BDs are generally considered to be some of the best engines Lycoming ever built.
What you did have were certain cranks that couldn't handle it well, both from Lycoming and Continental.
Right, and a 'crank has to be removed at next overhaul' would have taken care of that.
Correct. And really this seems to be a better compromise between "remove every one of these cranks now" and "let them run indefinitely."
I am gathering information for an upcoming overhaul at this time. I really want to tear my grey hair out about the crummy options available. Do I want to AD riddled cylinders from chinese company A or failure prone cylinders from chinese company B or cylinders that shed their nickel coating from company C ?
I don't remember what kind of plane you have, but I do understand where you're coming from since we just did the engines on the 310. It wasn't an easy decision, mainly because of the various problems out there. While I'm confident in the work Charlie did, I'm less confident in some components, especially the cylinders. Only time will tell if we made a good choice or not.
Good points being made here in this discussion, one of them being that Lycoming figured, considering all of what they DIDN'T know, it would be prudent to ensure that ALL of the suspected cranks be sent to the landfill.
Just to be clear, this is something that you wouldn't see Ford, GM, or even Honda know any better.
It's just unfortunate that the General Aviation community had to end up funding this SNAFU which is a direct result of corporate corner cutting and outsourcing in a frivolous attempt to dodge liability and reap more profit.
I'll leave the outsourcing discussion out of this other than to say that I agree that outsourcing creates many problems, as has been shown historically.
To say the GA community had to fund this isn't entirely accurate. Lycoming's insurance had to fund a great deal of it. The reality is that the customers who have to replace their cranks at overhaul may have had to replace them anyway for other reasons, as well. Most wouldn't have, agreed, but some would. On the whole, it's easy to say that it's a stupid thing when you have to pay something you didn't want to pay. Suddenly it makes more sense when you see lawsuits over things like a crank snapping in a Navajo, the pilot handles the engine failure wrong and blows up the other engine due to detonation so bad that all 6 pistons looked like warm butter when retrieved from the bottom of the ocean, and ultimately kills all 10 people on board.
You can't have a brand name without earning it and once you do you have to protect it.
Agreed fully. Unfortunately we have been suffering issues with this.
...IMHO...