What was found
ON INITIAL CLIMB AT APPROX 500 AGL, RECEIVED LAV SMOKE WARNING EICAS. SMOKE ODOR IN COCKPIT, SMOKE NOT VISIBLE. SMOKE MASKS DONNED AND EMERGENCY RETURN TO FIELD INITIATED. F/A REPORTED CLOUD OF SMOKE MOVING THROUGH CABIN. CABIN BRIEFED FOR PRECAUTIONARY EVACUATION AFTER LANDING. NO VISIBLE FIRE OR SMOKE AFTER INITIAL CLOUD. MX RAN ENGINES WITH NO PROBLEMS NOTED. BLEED DUCTS WERE INSPECTED FOR EVIDENCE OF OIL. NO EVIDENCE NOTED IN INLET OR TAILPIPE. UNABLE TO FIND ANY DEFECTS. A/C WAS TEST FLOWN WITH NO LAV SMOKE MESSAGES OR SMOKE ODOR NOTED. OPS CHECK GOOD. ENGINE SERIAL NUMBERS CAE312670 AND CAE312675.