the pilot's intentional flight into known icing conditions and his overconfidence in his ability, which led to a partial loss of engine power as a result of induction system ice. Also causal was ATC's excessive vectoring of the airplane in icing conditions, further deteriorating the airplane's performance, and thereby placing the airplane beyond gliding distance to a nearby airport. In addition, the pilot failed to maintain airspeed during the forced landing, which resulted in a stall. The icing conditions were a factor.