Feb. 18, 1943: The second of Boeing's top-secret XB-29 prototype bombers caught fire 20 minutes after takeoff from Boeing Field and crashed into the Frye Packing Plant. Lead Boeing test pilot Eddie Allen and 10 crewmen perished along with 19 workers in the meat processing factory. While the event could not be concealed, the identity of the aircraft type -- which would drop the first atomic bombs on Japan -- remained classified until the end of World War II .