What was found
AFTER DEPARTING AT APPROX 200 FEET AGL, FLIGHT CREW NOTED IN THE COCKPIT AN ODORLESS SMOKE LIKE MIST COMING FROM THE COPILOT SIDE. CREW QUICKLY DAWNED OXYGEN MASKS & DECLARED AN EMER. WHILE EXECUTING THE CHECKLIST, THE SMOKE CLEARED WITHIN A FEW MINUTES & THEY WERE VECTORED BACK & LANDING WITHOUT INCIDENT. DURING TROUBLESHOOTING FOUND THE COCKPIT ACM FAILED, PN 738384-33. UNIT WAS REPLACED WITH A NEW STYLE ACM, LEAK & OPERATIONAL CHECKS WERE NORMAL. ACFT WILL BE RELEASED TO SERVICE WHEN ADDITIONAL MX IS COMPLETE.