As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BNA-PHL - FLT 478 - DURING CLIMB-OUT, THE RIGHT HYDRAULIC SYSTEM QUANTITY WAS LOST. THE AIRCRAFT RETURNED TO THE FIELD AND LANDED WITHOUT INCIDENT. A MANUAL LANDING GEAR EXTENSION WAS REQUIRED. MAINTENANCE REPLACED THE RIGHT SPOILER CONTROL VALVE. (M)