On May 25, 1979, American Airlines flight 191 crashed very shortly after taking off from Chicago's O'Hare Airport. The flight crashed nearby in a Chicago suburb called Des Plaines.
All 271 people on board died as did 2 more on the ground in the crash.
They know, mechanically, why the flight crashed. Wikipedia has that. Was it an accident or intentional, though? Wikipedia has a thread to tug upon there too.
People who have listened to Once Bitten episode 562 know who was on that flight and why that flight went down.
