What was found
DURING CRUISE, LT MANIFOLD INFLIGHT DECAY CHECK FAILED 30-20 PSI IN ONLY 1.5 SECONDS. CREW RETURNED A/C AND LANDED W/O INCIDENT. ON THE GROUND, DECAY CHECK WAS 5 SECONDS. RT MANIFOLD GROUND DECAY FAILED 30-20-PSI IN ONLY 5 SECONDS. UPON INSPECTION MX FOUND LEAKING DUCT CLAMPS IN CROSS WING MANIFOLD. TIGHTENED AND REPLACED AS NECESSARY. FOUND PRESSURE RELIEF VALVES ON NR 1 AND 3 WOULD NOT CLOSE ON SCHEDULE, ALSO, FOUND LT FLOW CONTROL VALVE LEAKING THROUGH VALVE WHEN CLOSED. FOUND NR 4 WING ANTI-ICE VALVE LEAKING, CENTER SLOTTED EXTEND WING VALVE BLEED AIR DUCT LT SIDE LEAKING AT CLAMP AND A BROKEN DUCT FLANGE. ALL VALVES AND DUCTS WERE REPLACED PER ALL APPLICABLE MANUALS AND A/CT WAS RETURNED TO SERVICE.