As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HYD 3 LO PRESS CAUTION MSG IN FLIGHT; 0 PERCENT HYDRAULIC FLUID INDICATION. EMERGENCY DECLARED. FOUND LOOSE LINE ON 3B HYD PUMP. TIGHTENED LINE & OP/C CHECKS NORMAL & LEAKS CHECKS GOOD. FOUND HYD LEAKING WHICH WAS CAUSED BY A DAMAGED O-RING. REMOVED AND REPLACED O-RING. SERVICED HYD SYSTEM NR 3A IAW AMM 12-12-29. PERFORMED OPS CHECK. NO LEAK FOUND. A/C OK FOR RETURN TO SVC.