As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN FLIGHT, THE HYDRAULIC SYSTEM 1 LEAKING 1 GALLON IN 2 MINUTES. LEVEL ONE HYDRAULIC SYSTEM OFF DISPLAYED BELOW 2.5 GALLONS REMAINING. RETURNED TO DEPARTURE. FOUND THE HYDRAULIC OUTBOARD SUPPLY LINE LOOSE IN THE NR 1 PYLON. TORQUED IAW AMM 20-50-01. OPS & LEAK CHECKED NORMAL, NO LEAKS NOTED.