As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER GEAR RETRACTION, CREW BECAME AWARE OF AN ACRID ODOR WHICH INTENSIFIED. INITIAL ODOR WAS OF BURNING RUBBER OR A SMOLDERING WIRE BUNDLE. CREW WENT ON OXYGEN AND RETURNED TO IND. PERFORMED FIRE, SMOKE, FUMES AND ODOR CHECKLIST. REPLACED BOTH WATER SEPARATOR SOCKS. FOUND LT SOCK EXTREMELY DIRTY AND SMELLED OF DE-ICE FLUID. CHECKED ACM OIL LEVELS, FOUND NORMAL. RAN ALL 3 ENGINES IAW JRH. RUN WAS NORMAL. NO ODOR PRESENT. REF. M/M 21-51-032.