CL65 CREW HAD SMOKE IN THE COCKPIT AFTER TKOF AT CVG.

Narrative

SHORTLY AFTER TKOF; SMOKE STARTED TO ENTER THE COCKPIT. WE DONNED OUR OXYGEN MASKS AND ADVISED THE TWR THAT WE WERE RETURNING FOR LNDG AND DECLARING AN EMER. WE RAN ALL OF THE APPROPRIATE CHKLISTS; CONTACTED OUR DISPATCHER; AND SPOKE TO THE FLT ATTENDANT AND PAX. WE LANDED WITHOUT FURTHER INCIDENT AND TAXIED THE ACFT TO THE GATE WHERE WE WERE MET BY CUSTOMER SVC PERSONNEL; MAINT; AND THE FIRE DEPT. THIS WAS OUR FIRST FLT OF THE TRIP. WHEN WE FIRST ARRIVED AT THE ACFT; MAINT WAS DEFERRING THE APU; SO WE NEEDED AN AIR START. THE NEXT DAY WE FOUND OUT THAT THE CAUSE OF THE SMOKE WAS FROM THE APU CONTAMINATING THE ENVIRONMENTAL SYS. SUPPLEMENTAL INFO FROM ACN 541089: FLT WAS FIRST LEG OF 4 DAY TRIP. GOT TO ACFT AND FOUND MAINT WORKING ON APU. WE CONTINUED PREFLT AND EVENTUALLY MAINT DEFERRED APU. CAPT AND I DECIDED TO DO A 'BLEEDS OPEN' TKOF BECAUSE OF OUR LIGHT WT. REST OF GND OPS NORMAL. UPON INITIAL TKOF; IMMEDIATELY AFTER GEAR RETRACTION; SMOKE FILLED COCKPIT. I PUT ON MY MASK; TOOK CTL OF ACFT UPON CAPT'S DIRECTION; THEN CAPT DONNED HIS MASK. I THEN GAVE CTL BACK TO CAPT. I CONTACTED DEP AND INFORMED THEM WE NEEDED AN EMER RETURN TO ARPT. THE CAPT THEN TOOK THE ATC RADIOS AND FLEW WHILE WE CLEANED UP THE ACFT; DID NORMAL AND EMER CHKLISTS; AND CONTACTED DISPATCH. WE WERE AIRBORNE APPROX 20 MINS; YET IT SEEMED LIKE 2! I SPOKE TO THE FLT ATTENDANT; PAX; THEN TOOK ATC RADIOS. LNDG WAS UNEVENTFUL. WE TAXIED TO GATE AND DID A NORMAL EGRESS. SUBSEQUENTLY; WE WERE TOLD THAT OIL FROM APU LEAKED ONTO/INTO PACKS; WHICH CAUSED THE SMOKE.