The cause of the failure is unknown
There is no way to know if there was damage at the fly-in. I will ask the owner, (he lives in another city), to look at the crack at the trailing edge to see if there is obvious damage that might have led to the crack.
The elevator had a balance weight on it that was ~9 oz too heavy. It would seem that it might provide torsional flexing in rough air and is suggested as a possible factor. It is likely that some degree of metal fatigue may have occurred before the subject flight. We don''t know...
I think that if it had fluttered it might be gone, possibly along with part of the tail. The concern is that without rigidity it would seem more prone to flutter and he considers himself lucky to have landed in one piece..
The elevator is being preserved intact in case someone with more knowledge in evaluating structural failures wishes to have a look at it...
Okanagan Valley BC, Canada
RV-8 Completed Dec 2013
Membership renewed Nov 25, 2018