As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED. ON TAKEOFF, A DIRTY OIL/SOCK ODOR EMITTED FROM AIR CONDITIONING PACKS. ACCOMPLISHED CABIN CONTAMINATION CHECK IAW AMM 21-00-21. RAN BOTH ENGINES WITH NO ODOR NOTED. REPLACED LEFT RECIRCULATION FILTER IAW AMM 21-25-02. OPERATIONAL CHECK GOOD. SEE ALSO AALA20170117003.