What was found
DIRTY SOCK SMELL NOTICIED AT APPROX 6000 FEET PRIOR TO LANDING, HIGH PRESSURE VALVE SECURED CLOSED. PERFORMED BOROSCOPE OF THE NR 2 ENGINE. FOUND NO EVIDENCE OF INTERNAL OIL LEAKAGE OR OTHER DEFECTS. INSPECTED BEHIND NR 2 ENGINE INLET CONE. NO EVIDENCE OF OIL LEAKAGE FOUND. R & R BOTH CABIN RECIRCULATION FILTERS IAW AMM 21-21-41. R & R BOTH OZONE FILTERS IAW AMM 21-51-41. RAN BOTH ENGINES AND APU IN MULTIPLE BLEED CONFIGURATIONS AND NO UNUSUAL ODORS WERE OBSERVED. ACFT OK FOR CONTINUED SERVICE. REACTIVATED THE NR 2 ENGINE HP VALVE.