273: On May 25, 1979, American Airlines Flight 191, a McDonnell Douglas DC-10-10, crashed shortly after lifting off the runway at Chicago O'Hare Airport after the number one (left) engine and pylon separated from the wing. This broke hydraulic lines, causing leading edge lift devices to retract on that side of the aircraft and resulted in asymmetrical lift and loss of control. The accident was attributed to improper maintenance procedures.