Narrative:

About 3-5 minutes after takeoff I noticed an odd smell; something like plastic permeate the cockpit. I looked back and at first I didn't see anything; but a few moments later I looked back and saw what looked like a mist building in the cabin. At this point I decided to return. I asked the first officer to tell ATC we needed to return. He did this and then he also told them that we had smoke in the cabin. I then turned around and told the passengers that we were returning. They agreed we should; and also said it smelled like plastic. I'm not sure at what point but I asked the first officer to declare an emergency as well; and he requested the fire trucks with ATC. At this point I had the first officer look in the back of the QRH at the non-EICAS message producing checklist; which directed him to the smoke/fume removal checklist. We then executed this checklist; which included dumping the cabin which we did. Around this time I called the duty manager (after trying to connect to maintenance); told him of the situation and also told him that we needed to dump fuel since we were over max landing weight. After we hung up I told ATC of our intentions to dump fuel; and they said that was fine. We executed the fuel dump checklist at about 3;000 ft over the water. We ended up landing at about 29;970 pounds. (Max landing is 30;000 pounds). We landed uneventfully; taxied in (followed by the fire trucks) and off loaded the passengers. They seemed fine; were happy with returning.

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Original NASA ASRS Text

Title: G200 Captain experiences smoke with a burnt plastic smell shortly after takeoff. After declaring an emergency they return to the departure airport. Fuel is dumped so as to land below maximum landing weight.

Narrative: About 3-5 minutes after takeoff I noticed an odd smell; something like plastic permeate the cockpit. I looked back and at first I didn't see anything; but a few moments later I looked back and saw what looked like a mist building in the cabin. At this point I decided to return. I asked the First Officer to tell ATC we needed to return. He did this and then he also told them that we had smoke in the cabin. I then turned around and told the passengers that we were returning. They agreed we should; and also said it smelled like plastic. I'm not sure at what point but I asked the First Officer to declare an emergency as well; and he requested the fire trucks with ATC. At this point I had the First Officer look in the back of the QRH at the non-EICAS message producing checklist; which directed him to the smoke/fume removal checklist. We then executed this checklist; which included dumping the cabin which we did. Around this time I called the Duty Manager (after trying to connect to Maintenance); told him of the situation and also told him that we needed to dump fuel since we were over max landing weight. After we hung up I told ATC of our intentions to dump fuel; and they said that was fine. We executed the fuel dump checklist at about 3;000 FT over the water. We ended up landing at about 29;970 LBS. (Max landing is 30;000 LBS). We landed uneventfully; taxied in (followed by the fire trucks) and off loaded the passengers. They seemed fine; were happy with returning.

Data retrieved from NASA's ASRS site as of July 2013 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.