A small mechanical problem in the back of a Toronto-bound DC-9 quickly turns deadly six miles in the air. As the cabin and cockpit fill with smoke, the crew desperately attempts an emergency landing. Against all odds, they successfully touch down, but 90 seconds after hitting the runway, the cabin erupts in flame, and 23 people still inside the plane are killed. See how this tragic end led to changes to make crews better equipped to fight fires.