Yesterday my wife and I were going to fly down to Sac Executive to pick up some oil, and while doing my preflight I noticed that one of the exhaust stacks felt a little different than the other one...not much, just a little. Another pilot came over and felt it and said it was fine, but he hadn't been pulling on them for the last year and didn't have much reference.
Instead of flying I pulled the cowling and removed the exhaust stack. Under the carb heat muff was a hairline crack extending 300 degrees around the pipe.
I don't know how long it would have taken for the stack to break off completely, or what the consequences of all that superheated air being pumped under the cowling next to the carburetor would have been, but I think an in-flight engine fire isn't out of the question.
I must be living right...not only did I find it on the ground, but I was at my hangar! Oh ya, and there's an aircraft exhaust welding shop twenty miles down the road.
