As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: ODOR IN FLIGHT DECK DESCENDING THOUGH 18,000 FEET UNTIL TAXI IN. OCCURRED IN FLIGHT DECK FIRST, THEN NOTICED IN CABIN ALSO BY 1ST FLIGHT ATTENDANT. SMELL REPORTED AS DIRTY/CHEMICALLY. ACCOMPLISHED CARD 26L00021001 SMOKE/TROUBLESHOOTING, FOUND HYDRAULIC FLUID IN KEEL BEAM AREA AND FOUND YELLOW SYSTEM HYDRAULIC DRAIN VALVE LEAKING. CLEANED HYDRAULIC FLUID IN AREA AND REMOVED AND REPLACED YELLOW HYDRAULIC SYSTEM RESERVOIR DRAIN VALVE IAW AMM 29-13-41.