What was found
WINDSHIELD CRACKED AT FL390, SEEMS TO BE OUTER PANE ONLY, NO FLUCTUATIONS IN PRESSURIZATION NOTED. R & R FIRST OFFICER`S WINDSHIELD IAW AMM 56-11-11-000-001 & AMM 56-11-11-400-001, OPERATIONS CHECKED GOOD. REPLACED WINDOW HEAT CONTROLLER SEE LOG PAGE 827954 ITEM 2.