What was found
DURING CRUISE FLIGHT, SMOKE /FUMES OF UNKNOWN ORIGIN, ODOR. SMOKE AND FUMES IN THE COCKPIT AND CABIN. ACFT DEPARTED AND DIVERTED. FOUND HYDRAULIC LEAK ON NR 2 ENGINE RETURN LINE WHICH WAS DRIPPING DIRECTLY ONTO A AIR SUPPLY DUCT. TIGHTENED HYD LINE AND CLEANED AIR DUCT. OPS CHECKED, NO FINDINGS. ACFT RETURNED WITHOUT INCIDENT.