As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BOS - FLT 1859 - EN ROUTE BOS-DCA, SHORTLY AFTER TAKEOFF BROUGHT GEAR AND FLAPS UP. FLAPS STOPPED AT SIX DEGREES. LOST HYDRAULIC PRESSURE. RETURNED BOS AND LANDED WITHOUT FURTHER INCIDENT. REPLACED NR 1 ENGINE HYDRAULIC PUMP. LEAK CHECKS GOOD. SYSTEM GROUND CHECKED NORMAL OPERATION. (M)