What was found
(CAN) DURING A ROUTINE FLIGHT, IT WAS NOTED DURING CRUISE, THE AUTO PILOT BECAME UNSERVICEABLE, ERATICALLY PITCHING UP UNCOMANDED. THE PILOTS DIS-ENGAGED THE AUTO PILOT AND THE FLIGHT CONTINUED WITHOUT COMPLICATIONS. TROUBLESHOT THE SYS, AND FOUND A FAULTY VERTICIAL GYRO THAT HAD BEEN INSTALLED 11 HRS PRIOR. THE VERTICIAL GYRO WAS REPLACED, THE SYS WAS GROUND FUNCTION CHECKED SERVICEABLE.