What was found
FLIGHT CREW REPORT AUTOPILOT OSCILLATIONS IN PITCH AXIS DURING CLIMB & CRUISE. AS A RESULT OF THE TROUBLESHOOTING INVESTIGATION OF THE FLIGHT CREW LISTED DEFECT, LINE MX DISCOVERED THAT THE ELEVATOR PCU CENTERING SPRING HAD FAILED IN THAT 1 LEG OF THE SPRING HAD BROKEN AWAY FROM THE MAIN SPRING. THE UNSERVICEABLE SPRING ASSEMBLY WAS REPLACED WITH A NEW ITEM & THE ACFT HAS BEEN RELEASED BACK TO SERVICE WITHOUT FURTHER OCCURRENCE OF THE DEFECT. THIS IS THE FIRST INSTANCE WHERE THIS DEFECT HAS BEEN IDENTIFIED ON THE OPERATORS FLEET & INDICATIONS FROM THE MFG IS THAT IT IS NOT A KNOWN DEFECT ON THE WORLD FLEET.