What was found
DURING A FUNCTIONAL CHECK FLIGHT FOR AN UNRELATED ITEM AND WHILE PERFORMING MANEUVERS INCLUDING 30 DEGREE TURNS IN CLIMB AND DESCENT, THE ELEVATOR TRIM POSITION MOVES INDEPENDENTLY WITHOUT INPUT FROM CREW; TENDS TO MOVE 3/4 TO FULL NOSE DOWN POSITION. THE AIRCRAFT WAS CONTROLLABLE AND LANDED SAFELY. THE AIRFRAME OEM INSTRUCTED THE REPLACEMENT OF ELEVATOR TRIM ACTUATOR WITH IMPROVED VERSION REPORTED IN TECNAM SB-372-CS DATED 03/10/2020.