Almost 52 years ago, on June 29th, 1972, a North Central Airlines Convair CV-580 collided in mid-air with an Air Wisconsin de Havilland Canada DHC-6 Twin Otter over Lake Winnebago, killing all 13 passengers and crew. Located in the north-central state of Wisconsin, Lake Winnebago is a shallow freshwater lake, measuring some 30 miles long and 10 miles wide.