As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAKEOFF, SMELT SMOKE & FIRST OFFICER WAS COVERED IN A WHITE SUBSTANCE. RETURNED TO AIRPORT. DEFERRED LT AIR CONDITIONING PACK IAW MEL 21-51-1B. CAT C PLACARD INSTALLED. R & R LT ACM PN ON & OFF GG670-95009-5, SN OFF 00622 SN. EMER WAS DECLARED.