Mine was when I decided to convert my wing mounts from rubber bands to bolts. I epoxyed in some plywood mounts with blind nuts. After waiting about 2 hours I decided to take it out for a test flight. According to the epoxy label it should be "full strenght in one hour". I was trimming it to a level flight at about 400 feet over head, when the wing seperated from the fuslage. I was so stunned that I watched the wingless plane nose dive into a corn field at full throtle. About 30 seconds later th wing twisted down relatively close to me. I recovered all the peices and have made progress in rebuilding.