As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SHORTLY AFTER TAKEOFF, THE NR 2 HYDRAULIC LIGHT ILLUMINATED. RETURNED TO MORGAN CITY. MAINTENANCE FOUND A JAM NUT ON A FITTING ON THE HYDRAULIC MANIFOLD SPLIT ALLOWING THE PACKING TO UNSEAT UNDER PRESSURE CAUSING THE LOSS OF HYDRAULIC FLUID. REPLACED THE NUT AND PACKING. ALSO REPLACED THE HYDRAULIC PUMP AS A PRECAUTION DUE TO IT RUNNING DRY.