The Europa which shook itself to bits and lost a wing fatally injuring the new owner not so long ago had a severe construction error in which the wing fixings had shifted during fibreglassing and subsequent drilling was not central: the intended 'O' shaped hole in a structural metal part became a 'C' shaped hole with fatal results some years later.
I can't find the AAIB report but the error was totally un detectable as it had been layered over.
This sort of mishap would put me off a permit aircraft.......
Cusco