What was found
AT 3,000 FT MSL, PRETTY STRONG ODOR (DIRTY SOCK). STAY ON UNTIL GATE. DOOR OPEN AND WINDOW. C/A: WORK IN CONJUNCTION WITH LP 1821932 MSI. RAN BOTH ENGINES, BOTH PACKS, AND APU BLEED. ISOLATED EACH SYS. NO SMELLS. RAN BOTH ENGINES AT POWER FOR 15 MINS. CHANGED RECIRC FILTERS. RAN AGAIN, STILL NO SMELLS. NO HISTORY. MCC NOTIFIED. A/C OK FOR SVC. (LP: 9334514, AIRCRAFT WAS GROUNDED)