On the afternoon of May 25, 1979, the McDonnell Douglas DC-10 operating this flight was taking off from runway 32R at O'Hare International when its left engine detached from the wing, causing a loss of control.

The disrupted and unbalanced aerodynamics of the aircraft caused it to roll abruptly to the left until it was partially inverted, reaching a bank angle of 112°, before crashing in an open field by a trailer park near the end of the runway.

[9] On the accident flight, during the takeoff rotation, the number-one engine and its pylon assembly separated from the left wing, ripping away a 3-foot (1 m) section of the leading edge with it.

[1]: 2  Robert Graham, supervisor of maintenance for American Airlines, stated: As the aircraft got closer, I noticed what appeared to be vapor or smoke of some type coming from the leading edge of the wing and the number-one engine pylon.

The only crash-related audio collected by the recorder is a thumping noise (likely the sound of the engine separating), followed by the first officer exclaiming, "Damn!

To reach that backup power switch, the flight engineer would have had to rotate his seat, release his safety belt, and stand up.

[1]: 52 The aircraft climbed to about 325 feet (100 m) above ground level while spewing a white mist trail of fuel and hydraulic fluid from the left wing.

The aircraft was destroyed by the impact force and ignition of a nearly full load of 21,000 US gallons (79,000 L; 17,000 imp gal) of fuel; no sizable components other than the engines and tail section remained.

[19] The memorial, a 2-foot-high (0.6 m) concave wall with interlocking bricks displaying the names of the crash victims, was formally dedicated in a ceremony on October 15, 2011.

[22] Thirty victims whose remains were never identified are buried at Green Hills Memorial Park in Rancho Palos Verdes, California.

The impact on the public was increased by the dramatic effect of an amateur photo taken of the aircraft rolling that was published on the front page of the Chicago Tribune on the Sunday two days after the crash.

[1]: 26 If the forklift had been positioned incorrectly, the engine/pylon assembly would not be stable as it was being handled, causing it to rock like a seesaw and jam the pylon against the wing's attachment points.

[1]: 29–30  Regardless of how it happened, the resulting damage, although insufficient to cause an immediate failure, eventually developed into fatigue cracking, worsening with each takeoff and landing cycle during the eight weeks that followed.

[1]: 12 Inspection of the DC-10 fleets of the three airlines revealed that while United's hoist approach seemed harmless, several DC-10s at both American and Continental already had fatigue cracking and bending damage to their pylon mounts caused by similar maintenance procedures.

[1]: 18  The field service representative from McDonnell-Douglas stated the company would "not encourage this procedure due to the element of risk" and had so advised American Airlines.

Unlike other aircraft designs, the DC-10 was not equipped with a separate mechanism that would lock the extended leading-edge slats into place, relying instead solely on the hydraulic pressure within the system.

An examination of eyewitness photographs showed only that the right wing slats were fully extended as the crew tried unsuccessfully to correct their steep roll.

The position of the left wing slats could not be determined from the blurry color photographs, so they were sent to a laboratory in Palo Alto, California, for digital analysis, a process that pushed the limits of 1970s technology and necessitated large, complicated, and expensive equipment.

[10]: 20–21 Wind-tunnel and flight-simulator tests were conducted to help understand the aircraft's trajectory after the engine detached and the left wing slats retracted.

The partial electrical power failure, produced by the separation of the left engine, meant that neither the stall warning nor the slat retraction indicator was operative.

"[1]: 54 The findings of the investigation by the NTSB were released on December 21, 1979: The National Transportation Safety Board determines that the probable cause of this accident was the asymmetrical stall and the ensuing roll of the aircraft because of the uncommanded retraction of the left wing outboard leading edge slats and the loss of stall warning and slat disagreement indication systems resulting from maintenance-induced damage leading to the separation of the No.

Contributing to the cause of the accident were the vulnerability of the design of the pylon attachment points to maintenance damage; the vulnerability of the design of the leading-edge slat system to the damage which produced asymmetry; deficiencies in Federal Aviation Administration surveillance and reporting systems, which failed to detect and prevent the use of improper maintenance procedures; deficiencies in the practices and communications among the operators, the manufacturer, and the FAA, which failed to determine and disseminate the particulars regarding previous maintenance damage incidents; and the intolerance of prescribed operational procedures to this unique emergency.

[34][35] It also enacted a special air regulation banning the DC-10 from U.S. airspace, which prevented foreign DC-10s not under the jurisdiction of the FAA from flying within the country.

Once the FAA was satisfied that maintenance issues were primarily at fault and not the actual design of the aircraft, the type certificate was restored on July 13, and the special air regulation was repealed.

"[1]: 94 In the wake of the grounding, the FAA convened a safety panel under the auspices of the National Academy of Sciences to evaluate the design of the DC-10 and the U.S. regulatory system in general.

The panel's report, published in June 1980, found "critical deficiencies in the way the government certifies the safety of American-built airliners", focusing on a shortage of FAA expertise during the certification process and a corresponding overreliance on McDonnell Douglas to ensure that the design was safe.

Writing for The Air Current, aviation journalist Jon Ostrower likens the panel's conclusions to those of a later commission convened after the 2019 grounding of the Boeing 737 MAX.

The Western crash, however, was due to low visibility and an attempt to land on a closed runway,[39][40][41] through, reportedly, confusion of its crew.

[29] The Antarctic sightseeing flight hit a volcano,[43][44][45] though this was caused by several human and environmental factors not related to the airworthiness of the DC-10, and the aircraft was later completely exonerated.

[51] The accident was also discussed in "Breaking Point", the second episode of the first season of TV show Why Planes Crash on MSNBC.