As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING THE CRUISE, THE CAPTAIN NOTICED THE HYDRAULIC QTY ON THE NR 1 SYS HAD REDUCED FROM 55 PERCENT TO 40, BEFORE DEPARTURE THE CREW HAD SEEN THE QUANTITY ABOUT 75-80 PERCENT. A TECHLOG ENTRY WAS MADE. THE ENGINEERS REPORTED THAT A LEAK IN THE LOWER FUSELAGE UNDER THE CABIN, BENEATH THE WING, WAS FOUND. WHEN WE LT THE ACFT THE QTY WAS 15 PERCENT. BALANCE RELIEF VALVE LEAKING, PART REPLACED.