American Airlines Flight 191 Took Off Normally—Seconds Later, Everything Changed
On May 25, 1979, American Airlines Flight 191 was preparing to leave Chicago's O'Hare International Airport for Los Angeles.
At first, there was nothing unusual about the departure.
The McDonnell Douglas DC-10 was accelerating down the runway on a clear afternoon. Passengers were expecting an ordinary flight across the country.
Then, during takeoff, a catastrophic mechanical failure changed everything.
Within moments, the aircraft lost its left engine and part of the wing structure, suffered a devastating loss of control, and crashed shortly after becoming airborne.
The tragedy became one of the deadliest aviation accidents in U.S. history.
A Routine Takeoff
Flight 191 was operating from O'Hare's Runway 32R. According to the National Transportation Safety Board, weather conditions were clear, with visibility of approximately 15 miles.
The aircraft began its takeoff normally.
But during the rotation—the moment when the aircraft's nose rises from the runway—the No. 1 engine and its pylon assembly separated from the left wing.
Approximately three feet of the wing's leading edge also separated.
The engine and pylon fell onto the runway while the aircraft continued into the air.
For the pilots, the situation was extraordinarily difficult.
The aircraft was still capable of climbing, but the separation had caused extensive damage to systems associated with the left wing.
The Seconds That Followed
Flight 191 climbed to roughly 325 feet above the ground.
Then the aircraft began rolling to the left.
The roll continued until the wings passed the vertical position, while the nose pitched downward. The airplane ultimately crashed into an open field northwest of the runway, with wreckage spreading toward a nearby mobile-home park.
The entire sequence unfolded extraordinarily quickly.
The crew had almost no time to understand the full extent of the mechanical failure before the aircraft became uncontrollable.
Why the Engine Separation Was So Dangerous
The loss of an engine during takeoff is an emergency that commercial aircraft are designed to handle.
But Flight 191's situation was different.
The engine and pylon separation damaged hydraulic lines and caused the loss of hydraulic pressure in the affected area. This contributed to the retraction of the outboard leading-edge slats on the left wing.
The aircraft consequently developed a dangerous imbalance in lift between the two wings.
The Federal Aviation Administration explains that the crew responded as they would to an engine failure. However, because the damaged wing had undergone an unexpected configuration change, reducing the aircraft to the prescribed speed resulted in a stall of the left wing.
The aircraft then entered an uncontrollable left roll.
A Terrible Loss of Life
Everyone aboard Flight 191 was killed.
The NTSB records 271 people aboard the aircraft as fatalities. Two people on the ground also died, while two others on the ground were injured.
The aircraft was destroyed in the crash and subsequent fire.
The tragedy also affected people who had nothing to do with the flight itself because the crash occurred near an area containing homes and a mobile-home park.
What had begun as an ordinary airline departure had become a disaster within seconds.
The Investigation Looked Beyond the Engine
The accident initially appeared to involve a catastrophic engine failure.
But investigators eventually determined that the story was more complicated.
The NTSB concluded that the probable cause was an asymmetrical stall and resulting roll caused by the uncommanded retraction of the left wing's outboard leading-edge slats.
That slat problem was linked to damage associated with the separation of the engine and pylon assembly.
Investigators traced that structural failure to improper maintenance procedures that had damaged the pylon structure.
In other words, the disaster was not simply a matter of an engine suddenly stopping.
A chain of mechanical and maintenance-related problems ultimately created an emergency that the aircraft could not survive.
Maintenance Became a Major Focus
The investigation examined how the engine and pylon had been handled during maintenance.
The NTSB found that improper maintenance procedures had contributed to damage that eventually allowed the pylon structure to fail.
Investigators also identified broader issues involving the aircraft's design, maintenance practices, communication among the airline, manufacturer and regulators, and FAA oversight.
The accident therefore became an important lesson in how seemingly separate safety weaknesses can combine into a catastrophic chain of events.
The Crew Faced an Emergency They Could Not Fully See
One of the most tragic aspects of Flight 191 was that the pilots were dealing with consequences that were not immediately obvious from the cockpit.
They knew they had experienced what appeared to be an engine failure.
But the separation of the engine and pylon had also damaged systems and changed the aerodynamic configuration of the aircraft.
According to the FAA's account, the separation caused the loss of electrical power from the affected engine's generator. Several systems and instruments were consequently lost, including the captain's flight instruments, the left stall-warning system, and other indications that could have helped the crew understand the developing emergency.
The crew was therefore confronted with an extraordinary combination of failures during one of the most demanding phases of flight.
A Disaster That Changed Aviation Safety
The Flight 191 investigation produced numerous safety recommendations.
The accident highlighted the importance of proper maintenance procedures, accurate communication of maintenance-related problems, and effective regulatory oversight.
It also demonstrated how an aircraft can remain apparently flyable immediately after a major mechanical failure while nevertheless being placed in an extremely dangerous aerodynamic condition.
The lessons from the crash extended far beyond American Airlines.
Aviation safety depends on layers of protection: aircraft design, maintenance procedures, inspections, pilot training, warning systems, regulatory oversight, and communication throughout the industry.
When several of those protections fail simultaneously, the consequences can be catastrophic.
Remembering the People
More than four decades later, Flight 191 remains a painful reminder that aviation accidents are ultimately about people rather than statistics.
The passengers were traveling for different reasons. Some were heading toward California for business or vacation. Others were returning home or beginning a journey.
The crew was performing what should have been a routine flight.
None knew that their departure would become one of the defining aviation tragedies in American history.
Remembering Flight 191 therefore means remembering not only the mechanical failures and investigation findings, but also the hundreds of lives lost that afternoon.
The Bottom Line
American Airlines Flight 191 did begin its takeoff normally on May 25, 1979.
During rotation, however, the aircraft's left engine and pylon assembly separated from the wing, taking part of the wing's leading edge with them. The resulting damage caused the left-wing slats to retract and ultimately produced an asymmetrical stall and uncontrollable roll.
The DC-10 crashed near Chicago's O'Hare International Airport shortly after takeoff.
All 271 people aboard died, along with two people on the ground.
The NTSB ultimately traced the probable cause to a combination of maintenance-induced structural damage and the aerodynamic consequences that followed the engine and pylon separation.
What makes Flight 191 so haunting is how quickly an ordinary takeoff turned into an irreversible disaster—and how the investigation afterward revealed that the tragedy was not caused by one isolated failure, but by a chain of vulnerabilities that aviation safety authorities would spend years working to address.
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