What was found
AIRCRAFT WAS GROUNDED: DIRTY SOCK ODOR ON TAXI OUT APPROACH AND LANDING. DID NOT OBSERVE ODOR IN CRUISE. MAINTENANCE ISOLATED THE SOURCE OF THE ODOR TO THE APU. MAINTENANCE ACCOMPLISHED APU SMOKE/ODOR/FUME TROUBLESHOOTING TASK CARD 26L00021002 WITH NO ACTIVE LEAKS BEING NOTED. HOWEVER, MAINTENANCE NOTICED A BUILD UP OF CONTAMINATES IN THE APU PLENUM ELBOW AND CLEANED THE APU AIR INTAKE PER TASK CARD 26T31049006 ALONG WITH CLEANING THE APU COMPARTMENT PER AMM 49-00-00-100-03-A. THE ENVIRONMENTAL CONTROL SYSTEM WAS DECONTAMINATED PER TASK CARD 26L00021004. A SATISFACTORY LEAK OPERATIONAL CHECK WAS ACCOMPLISHED WITH NO LEAKS OR ODROS BEING NOTED.