As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BOS - FLT 2018 - EN ROUTE ORD-BOS - LOSS HYDRAULIC FLUID FROM LEFT HYDRAULIC SYSTEM. DECLARED EMERGENCY AND LANDED BOS WITHOUT INCIDENT. TIGHTENED LOWER B-NUT ON LEFT REVERSER CONTROL VALVE, REPLACED LEFT ENGINE DRIVEN PUMP, AND REPLACED PRESSURE CASE DRAIN AND RETURN FILTER. SYSTEM GROUND CHECKED NORMAL OPERATION. (M)