What was found
IN CRUISE, NOTICED ELEVATOR TRIM SNAPBACK WITH AUTOPILOT ENGAGED, FL 230 AND -31 DEGREES C. DISCONNECTED AUTOPILOT, MANUALLY ATTEMPTED TO MOVE TRIM, UNABLE TO MOVE TRIM. REGAINED TRIM CONTROL AT 4000 FT AND + 6 DEGREES. REPLACED RIGHT AND LEFT ELEVATOR TRIM TAB ACTUATORS IAW EMB 120 MM 27-32-02. OPS CHECK GOOD. P/N: 5299-1, S/N ON: 633, S/N OFF: 728, S/N ON: 938, S/N OFF: 535.