What was found
AIRCRAFT WAS GNDED. ACID BURNING OIL, SOCK SMELL AFTER TAKEOFF THRU 10,000', SUBSIDED AT CRUSE. RETURNED DESCENDING THROUGH 10,000' THRU LANDING. ACCOMPLISHED JC 26L00021001, 26L00036003 CABIN AIR QUALITY TROUBLESHOOTING. R & R HEPA FILTERS & AIR QUALITY IMPROVED AMM 21-21-41--PB 401.