What was found
DURING CLIMB, SHORTLY AFTER GEAR RETRACTION, SMOKE WAS NOTICED FILLING COCKPIT AND CABIN. TOWER WAS CONTACTED AND ADVISED AN IMMEDIATE RETURN TO AIRPORT. SMOKE SEEMED TO BE COMING FROM THE ENVIRONMENTAL SYS, IN TURN, SYS WAS SWITCHED OFF AND LANDING WAS UNEVENTFUL. MX DETERMINED RT ENGINE TO BE AT FAULT, DUE TO INTERNAL OIL LEAKAGE. RT ENGINE WAS REPLACED AND AN OPS CHECK FLIGHT PERFORMED. ALL CHECKED NORMAL, ACFT RETURNED TO SERVICE.