What was found
(CAN) LEADING EDGE RIB ASSEMBLIES ARE VERY DIFFICULT TO SEE.THE USE OF A MIRROR THROUGH THE HORIZONTAL SPAR AND RIB LIGHTNING HOLES IS THE ONLY WAY TO SEE THE CRACKS ALONG THE TABS.WE BELIEVE THE RIBS ARE CRACKING DUE TO IMPROPER GROUND HANDLING.THE PRACTICE OF PUSHING THE AIRCRAFTS TAIL DOWN BY ITS SPAR IN ORDER TO ROTATE THE AIRCRAFT IN POSITION MAY BE DAMAGING THESE RIBS. BOTH RIBS WERE REPLACED WITH NEW.THE TAIL SURFACES WERE REMOVED AND RE-INSTALLED.