As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LAX - CREW REPORTED DURING FLAP EXTENSION, "B" SYSTEM HYDRAULIC SYSTEM QUANTITY DROPPED TO ZERO. EMERGENCY DECLARED FLIGHT LANDED LAX WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. TIGHTENED "B" SYSTEM SUPPLY TUBE IN RIGHT WING B NUT THAT WAS FOUND LOOSE. SYSTEM GROUND CHECK NORMAL OPERATION.