What was found
ON DESCENT, NOTICED RUDDER FLUTTER. BOTH RUDDER INDICATION & AERODYNAMIC FLUTTER OBSERVED AT VARIOUS SPEEDS. ON THE GROUND, STILL OBSERVED RUDDER FLUCTUATIONS (ABOUT 3 DEGREES BOTH SIDES). AT FL330 AND MACH .77 EXPERIENCED AN UNCOMMANDED RUDDER MOVEMENT. VERIFIED BY FEELING A/C MOVE ABOUT VERT AXIS AND FLIGHT CONTROL PAGE. INSPECTED PRIMARY & SECONDARY BREAKOUT FORCE ON RUDDER FEEL MECHANISMS. WITHIN TOLERANCES PER 27-21-00. REPLACED NR 1 AND NR 2 FCC CIRCUIT CARD ASSEMBLIES. AUTOPILOT SYSTEM OPS CHECK GOOD IAW MM22-11-07.