American Airlines Flight 191 — 1979 aviation accident in Chicago, Illinois, United States
The deadliest aviation accident in U.S. history, killing 273 people after engine separation caused loss of control during takeoff at O'Hare.
Key Facts
- Total fatalities
- 273
- Occupants on board
- 271
- Ground fatalities
- 2
- Aircraft type
- McDonnell Douglas DC-10
- Crash distance from runway end
- 4,600 feet
- Maximum bank angle reached
- 112 degrees
By the Numbers
Location
Cause → Event → Consequence
Improper maintenance procedures at American Airlines had damaged the pylon structure connecting the left engine to the wing. During takeoff rotation, this damage caused engine number one to separate from the left wing, severing hydraulic lines that kept the leading-edge slats locked in place and damaging a 3-foot section of the wing's leading edge.
On May 25, 1979, as Flight 191 began climbing after takeoff from O'Hare's runway 32R, the detached left engine triggered uncommanded retraction of the outboard slats. The resulting aerodynamic imbalance caused the aircraft to roll abruptly left to a bank angle of 112 degrees, inverting partially before crashing into an open field near a trailer park approximately 4,600 feet from the runway end.
All 271 people aboard and 2 bystanders on the ground were killed, making Flight 191 the deadliest aviation accident in United States history. The NTSB investigation revealed systemic maintenance failures at American Airlines, prompting regulatory scrutiny of DC-10 maintenance practices and temporarily grounding the aircraft type across U.S. carriers.