What was found
EMERGENCY DECLARED - ECAM WARNING, BLUE SYSTEM LOW LEVEL, HYD QTY GAUAGES CONFIRMED LOW QUANTITY IN BLUE SYS. COMPLETED STEPS IN ECAM AND QRH PROCEDURES. VISUALLY INSPECTED AND FOUND BLUE HYD SYS SERVO CONTROL MANIFOLD NO NON RETURN VALVE LEAKING FROM THE EXTRACTOR PLUG. R & R NON-RETURN VALVE EXTRACTOR PLUG O-RING, IAW AMM 29-12-34-0401. SERVICED RESERVOIR, BLEEDING EFFICIENCY CHECK OK AND LEAK CHECK OK.