As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER DEPARTING PDX THE LEFT HYDRAULIC SYSTEM PRESSURE DECREASED. AIRCRAFT DIVERTED TO BIL. USED ALTERNATE GEAR AND FLAP EXTENSIONS AND LANDED UNEVENTFULLY. MAINTENANCE REPLACED RUDDER RATIO BYPASS VALVE. SAFETIED ALTERNATE EXTENSION SWITCH, CLOSED GEAR DOORS AND CYCLED FLAP BACK TO ZERO.