The airplane was destroyed when it impacted terrain at 1034 Eastern time. The Canadian certificated private pilot and the passenger were fatally injured. Visual conditions prevailed at the site; however, initiation of the event occurred in instrument conditions. According to preliminary information, the airplane was in cruise flight at 6200 feet msl, the minimum sector altitude (MSA) for that location, when the pilot reported airframe icing and requested a lower altitude. However, because of terrain, the controller gave the pilot a 30-degree left turn. Another pilot, in an airplane about 30 nm to the east, subsequently reported cloud tops at 7500 feet. The controller asked the pilot if he would like a climb to 8000 feet and the pilot responded that he would. About three minutes later, the pilot advised the controller that he was losing altitude. The controller told him to maintain whatever altitude he could, and advised him of the location of the nearest airport. There were no further communications from the airplane.