I had a bunch of emails from Kelly today. They were from Tim Gauntt, their Director of Warranty and Tech Support. Tim explained the issue with Kelly (Ford) alternators...
The looseness of the case is a mechanical issue on all the Ford-style alternators. The way the housings are fitted to the stator allows for movement after the alternator is heated up and run with a load, something which we cannot duplicate in production testing. This is why you found the housing bolts loose but still safety wired. We currently affix a decal to the housing and recommend the through bolts be re-torqued after the 1st 10 hours of operation and then each 100 hours thereafter. It’s been my experience the 1st 10 hour re-torque and the 1st 100 hour inspection will be all that’s needed.
The picture here was sent to me by John Miller, a South African journalist/editor who had this happen to another C182 in flight. I've also heard of another occurrence in the UK which sounds very similar. I (along with engineer Justin Cox) caught my alternator failure when the case was just starting to come apart, but I'm led to believe that this is how it would have ended had we not spotted it.
I can't say that I am hugely happy about a design that allows this kind of thing to happen, but I am happy that the conversation with Kelly is now two-way.
So, if you have a Kelly (Ford) alternator on your TCM engine you might want to get your engineer to check the torque next time you have the cowling off.
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