Captain,

well, the stats are not easy to come by. Those who manage to get back
to the airport without incident never show up in the stats. Then you'd
have to exclude the "obviously dumb" things like running out of fuel or
fuel mismanagement. Those will be the VAST, ABSOLUTELY OVERWHELMING
majority. The comes the problem of maintenance. Obviously, many people
are willing to fly with total junk that's never been maintained
properly. Does that fall under "mechanical engine failure" or "pilot
error"?

--
Thomas Borchert (EDDH)