What was found
A/C HAS A HEAVY YAW VIBRATION AND FLOOR VIBRATION ABOVE .72M AT FL 350. AT FL 280 VIBRATION STARTS AT .62M SPEEDBRAKES, CLIMB, DESCENTS AND TURNS HAVE NO EFFECT ON VIBRATION OR YAW. AIRCRAFT WAS FLOWN AT 62M AND FL280 FROM DAY-MEM. REMOVED LOWER TAB. FOUND BROKE TAB HINGES AND ATTACH HARDWARE WORN AND BROKEN. REPLACED LOWER TAB HINGES IAW MM 27-20-11. REPLACED LOWER TAB IAW MM 27-20-11 AND 27-20-00. OPS CHECK GOOD.