As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF CREW NOTED VISIBLE FUMES AND A HYDRAULIC SMELL IN THE COCKPIT. RETURNED AIRCRAFT TO DEPARTURE AIRPORT FOR MAINTENANCE. MAINTENANCE FOUND HYDRAULIC FLUID IN A PNUEMATIC DUCT AND DEBRIS UNDER THE SEAT OF THE HYDRAULIC RESERVOIR CHECK VALVE. CLEANED VALVE AND ALL ASSOCIATED DUCTS. OPS CHECK PERFORMED WITH NO DEFECTS NOTED.