This may be an obvious point, but CA hinges don't handle high frequency vibrations very well. I know for a fact an out of balance prop, espically on a high RPM 2-stroke can cause a failure. We proved it on a trainer that broke 2 elevator hinges in a row, the prop was changed and the problem went away, the student broke the new prop and put the old one back on and it broke a third hinge. Since then the prop has been replaced and with 30-40 more flights there have been no problems. Just check the balance before you condem the hinges or airframe.