Narrative:

Departed ZZZ at XA45. The PIC had just prior to start-up deferred a left ahrs platform and informed me that this was done legally and correctly. He failed to inform me that we had a VMC only requirement with this MEL. I was the PF as left side EFIS display had no compass/heading/pitch information. Takeoff and climb normal but at 8000 ft received a 'left oil temperature hi' caution EICAS. Performed QRH; required monitoring of temperatures which stabilized and continued flight. We obviously entered positive control area above FL180 without required equipment for IFR flight. On climb from FL260 to FL330 it occurred to me we could not fly in rvsm airspace as our autoplt was not engaging. We notified ATC on climb; and after receiving several 'stand by' and request for flight below rvsm airspace; we were reclred to FL270. We obviously had entered rvsm airspace up to around FL310 before descent. We then landed normally at ZZZ1 to pick up additional passenger for continuation of our flight to ZZZ2. The PIC was on phone to maintenance but failed to write up the oil temperature issue. Takeoff was normal but at approximately 10000 ft received another 'left oil temperature high' EICAS and also oily pack smoke entering cabin and cockpit. I donned mask; requested lower; 180 degree return to airport; and QRH. PIC (PNF) completed these: pressurization was dumped via 'ram' to clear smoke and returned to airport. The PIC refused to declare an emergency; asked for return to airport only. We both felt the aircraft needed to be on the ground as soon as possible and landed safely although at 400 pounds over maximum landing weight. Callback conversation with reporter revealed the following information: reporter stated the smoke in the cockpit was apparently caused by the engine oil being over serviced with the excess leaking out of the gearbox; through the engine bleed; into the pack; and then the cockpit and cabin. The over service was also believed to have caused the hi oil temperature EICAS warning because too much oil reduces the aeration cooling of the oil.

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Original NASA ASRS Text

Title: A G200 EXPERIENCED HI OIL TEMP EICAS WARNING AND OIL SMOKE IN THE COCKPIT ON CLBOUT. THE FLT CREW RETURNED TO THEIR DEPARTURE AIRPORT.

Narrative: DEPARTED ZZZ AT XA45. THE PIC HAD JUST PRIOR TO START-UP DEFERRED A L AHRS PLATFORM AND INFORMED ME THAT THIS WAS DONE LEGALLY AND CORRECTLY. HE FAILED TO INFORM ME THAT WE HAD A VMC ONLY REQUIREMENT WITH THIS MEL. I WAS THE PF AS L SIDE EFIS DISPLAY HAD NO COMPASS/HDG/PITCH INFO. TKOF AND CLB NORMAL BUT AT 8000 FT RECEIVED A 'L OIL TEMP HI' CAUTION EICAS. PERFORMED QRH; REQUIRED MONITORING OF TEMPS WHICH STABILIZED AND CONTINUED FLT. WE OBVIOUSLY ENTERED PCA ABOVE FL180 WITHOUT REQUIRED EQUIP FOR IFR FLT. ON CLB FROM FL260 TO FL330 IT OCCURRED TO ME WE COULD NOT FLY IN RVSM AIRSPACE AS OUR AUTOPLT WAS NOT ENGAGING. WE NOTIFIED ATC ON CLB; AND AFTER RECEIVING SEVERAL 'STAND BY' AND REQUEST FOR FLT BELOW RVSM AIRSPACE; WE WERE RECLRED TO FL270. WE OBVIOUSLY HAD ENTERED RVSM AIRSPACE UP TO AROUND FL310 BEFORE DSCNT. WE THEN LANDED NORMALLY AT ZZZ1 TO PICK UP ADDITIONAL PAX FOR CONTINUATION OF OUR FLT TO ZZZ2. THE PIC WAS ON PHONE TO MAINT BUT FAILED TO WRITE UP THE OIL TEMP ISSUE. TKOF WAS NORMAL BUT AT APPROX 10000 FT RECEIVED ANOTHER 'L OIL TEMP HIGH' EICAS AND ALSO OILY PACK SMOKE ENTERING CABIN AND COCKPIT. I DONNED MASK; REQUESTED LOWER; 180 DEG RETURN TO ARPT; AND QRH. PIC (PNF) COMPLETED THESE: PRESSURIZATION WAS DUMPED VIA 'RAM' TO CLR SMOKE AND RETURNED TO ARPT. THE PIC REFUSED TO DECLARE AN EMER; ASKED FOR RETURN TO ARPT ONLY. WE BOTH FELT THE ACFT NEEDED TO BE ON THE GND ASAP AND LANDED SAFELY ALTHOUGH AT 400 LBS OVER MAX LNDG WT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED THE SMOKE IN THE COCKPIT WAS APPARENTLY CAUSED BY THE ENGINE OIL BEING OVER SERVICED WITH THE EXCESS LEAKING OUT OF THE GEARBOX; THROUGH THE ENGINE BLEED; INTO THE PACK; AND THEN THE COCKPIT AND CABIN. THE OVER SERVICE WAS ALSO BELIEVED TO HAVE CAUSED THE HI OIL TEMP EICAS WARNING BECAUSE TOO MUCH OIL REDUCES THE AERATION COOLING OF THE OIL.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.