As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
VISIBLE SMOKE FILLED THE COCKPIT AND CABIN IMMEDIATELY AFTER TAKEOFF. POSSIBLY FROM PACKS. BEGAN TO DISSIPATE ON FINAL APPROACH RETURN TO ABI DECLARED EMERGENCY. C/A: PERFORMED ENGINE ODOR EVENT TROUBLESHOOTING SUPPLEMENT, IAW ETN-EM-72-034 REVISION NUMBER TEN.