What was found
DURING INSP, HORIZONTAL STABILIZER WAS FOUND TO BE LOOSE AT BOTH FORWARD SPAR MOUNT HOLES. ENTIRE EMPENNAGE WAS REMOVED FROM AIRFRAME FOR DETAILED INSP. BOTH HOLES AT STABILIZER SPAR AND FORWARD BULKHEAD WERE FOUND TO BE ELONGATED .316 INCH TO .319 INCH. BOTH SHIMS BETWEEN STAB AND BULKHEAD WERE EXTREMELY ELONGATED AND APPEAR TO HAVE BEEN COUNTERSUNK PRIOR TO INSTALLATION AT FACTORY. BOTH SHIMS REMOVED WERE A THICKNESS OF .080 INCH. BOLTS REMOVED FROM FWD SPAR MOUNTS WERE AN5-6A, WHICH IS CORRECT HARDWARE IAW MM. BOLTS INSTALLED FROM MFG DID NOT HAVE SUFFICIENT GRIP LENGTH TO SUPPORT TOTAL MATERIAL THICKNESS. RECOMMEND REAMING ALL 4 HOLES TO .371 IN TO .374 IN AND INSTALLING AN6-10A BOLTS.