It was the deadliest aviation disaster in U.S. history of its time. The 1979 crash of American Airlines Flight 191 terrified a nation and nearly put the DC-10 out of commission forever. Relive the horrific crash at Chicago's O'Hare International Airport that claimed 273 lives, and see how investigators, under intense pressure from the FAA, the media, and airline companies across the globe, finally identified the cause.