What was found
IN CRUISE FLIGHT NOTICED GREEN SYSTEM QUANTITY SLOWLY DROPPING INTO YELLOW RANGE. EVENTUALLY GOT TO THE RED DOT FOLLOWED BY THE ECAM ALERT FOR LOW SYSTEM QUANTITY. FOLLOW ECAM PROCEDURE. MFG L95B13-401, MSN - N/A. FOUND DEPRESSURIZATION RELIEF VALVE STUCK OPEN, REMOVED AND REPLACED DEPRESSURIZATION VALVE IAW 29-11-27-04, LEAK AND OPS CK GOOD.