What was found
UPON PILOT PREFLIGHT, IT WAS DISCOVERED THAT THE RIGHT HAND AILERON HAD SOMETHING LOOSE INSIDE MOVING AROUND. THE AIRCRAFT WAS BROUGHT INTO MAINTENANCE AND THE AILERON WAS REMOVED AND IT WAS DISCOVERED THAT PART OF THE BALANCE WEIGHT HAD COME LOOSE. THE LEADING EDGE OF THE AILERON WAS DRILLED LOOSE AND IT WAS DISCOVERED THAT A CENTER SECTION OF THE OUTBOARD BALANCE WEIGHT HAD BROKE OFF, APPROX 10 INCH PIECE. THE CAUSE IS UNKNOWN, IT BROKE AT THE CENTER RIVET AND THEN WORKED LOOSE. INSTALLED A WHOLE NEW BALANCE WEIGHT AND REINSTALLED AILERON BACK ON AIRCRAFT.