What was found
FLIGHT 625, ENROUTE LNY - HNL, AIR TURNBACK. DISCREPANCY: ON CLIMB OUT OF LNY, THE CREW NOTICED A LOUD AIR NOISE COMING FROM LEFT SIDE OF AIRCRAFT. CREW WAS UNABLE TO DETERMINE THE SOURCE OF THE NOISE, SO ELECTED TO RETURN TO LNY. AN EMERGENCY WAS DECLARED. AIRCRAFT LANDED WITHOUT FURTHER INCIDENT. CORRECTIVE ACTION: MAINTENANCE FOUND AND REMOVED DEBRIS ON COCKPIT COMMUNICATIONS DOOR. PERFORMED FUSELAGE PRESSURIZATION LEAK TEST. CHECKS GOOD WITH NO FURTHER DEFECTS.