What was found
DURING CENTER WINDSHIELD FRAME CHANGE DUE TO INTERGRANULAR CORROSION, COPILOT WINDSHIELD WAS REMOVED, REVEALING SEVERE INTERGRANULAR CORROSION ON LOWER WINDSHIELD SEAL MATING SURFACE OF FRAME. AFTER BLENDING CORROSION, SEVERAL AREAS MAPPED OUT TO PROTRUDE APPROXIMATELY 20-25 PERCENT INTO FRAME. THIS CORROSION IS NOT VISIBLE WITHOUT REMOVING WINDSHIELD. THE MANUFACTURER HAS APPROVED AN ULTRASONIC TEST PROCEDURE FOR THIS FRAME WHICH IS CURRENTLY IN THE FALCON 20 MAINTENANCE MANUAL TO CHECK FOR CORROSION IN THIS AREA WITHOUT REMOVING THE WINDSHIELD.