I seem to recall from the Flight Safety course at Wichita that in the event of icing retain height and trade speed to 105Kts and then trade height to retain 105Kts. Never never go below 105 even if it means ploughing into the ground at that speed. The instructor told us that in trials they had been unable to make the 'van stall at that speed, tho a 3 kt margin is a bit small.