American Airlines Flight 191 and UPS Flight 2976 were not identical accidents, but their similarities have drawn the attention of investigators and aviation safety experts.
On May 25, 1979, American Airlines Flight 191 began what should have been a routine mid-afternoon departure from Chicago O’Hare International Airport (ORD).
The plane, a McDonnell Douglas DC-10-10 bound for Los Angeles International (LAX), was carrying 258 passengers and 13 crew members. As he accelerated down runway 32R and spun in the air, the unthinkable happened. The left engine and pylon separated from the wing, tearing off a section of the leading edge as it separated. The engine fell onto the runway as the plane continued to climb, briefly reaching about 325 feet.
What followed happened in seconds.
With the engine off, the left wing leading edge slats retracted unevenly. That left wing stopped without warning and the DC-10 turned sharply to the left (its maximum pitch was recorded at 112º). Just 31 seconds after takeoff, it crashed in an open field near a trailer park, approximately 4,600 feet from the runway. All 271 people on board died, along with two people on the ground.
The NTSB later determined that the disaster was caused as a result of an asymmetric stall and resulting roll, caused by uncontrolled retraction of the left wing leading edge outer slats. The failure was due to maintenance-induced damage that led to the separation of the No. 1 engine and pylon assembly.
Investigators discovered that American Airlines’ maintenance procedure, which included the use of a forklift to support the engine and pylon during removal and reinstallation, had caused hidden structural damage to the pylon’s upper flange. The FAA subsequently grounded the DC-10 fleet for 37 days while inspections and repairs were carried out.
More than four decades later, Flight 191 remains the deadliest single-plane crash in U.S. history.
Aviation security expert Steve Forness, CEO of Air Flight Technical, later noted the design vulnerability exposed that day. In both the DC-10 accident and the subsequent UPS accident, he noticedthe engine appeared to rotate around the forward bulkhead before leaving the wing completely.
A reputation from which the DC-10 never fully recovered
The accident caused more than the destruction of an airplane. It severely (and permanently) damaged the DC-10’s reputation.
In the following days, the FAA temporarily revoked the aircraft’s type certificate, grounding all US-registered DC-10s and banning the use of foreign DC-10s in US airspace. Even after grids, warning systems and power supplies were fixed, public confidence never fully returned.
After Flight 191, the DC-10 became a symbol of risk to the flying public, whether that reputation was entirely fair or not. Sales suffered. McDonnell Douglas lost approximately $200 million in market value and production of the DC-10 ended in 1989, after 386 aircraft had been built.
Aviation has always had airplanes that were technically improved after a tragedy. But public perception may be harder to repair than metal.
Louisville: UPS Flight 2976
On November 4, 2025, another McDonnell Douglas trijet was taxiing down a runway when the story seemed to resonate chillingly.
UPS Airlines Flight 2976, an MD-11F freighter, departed Louisville Muhammad Ali International Airport (SDF) for Honolulu (HNL). The aircraft was built in 1991 and accumulated nearly 93,000 flight hours and more than 21,000 cycles. There were three crew members on board.
Shortly after V1 on runway 17R, the left engine and pylon separated from the aircraft.
The MD-11 climbed only about 30 feet before losing control. It crashed in an industrial area south of the airport, hitting several buildings and bursting into flames. All three crew members died, along with 12 people on the ground. One of those victims died from his injuries 51 days later, bringing the final death toll to 15. Another 23 people on the ground were injured.
It was the deadliest accident in UPS Airlines history.
The NTSB preliminary report and subsequent hearings identified fatigue cracks in the rear left pylon support, particularly in the rear and front lugs of the spherical bearing assembly. Researchers found that metal fatigue and excessive stress caused the failure.
The similarities to American Airlines Flight 191 were impossible to ignore. Both aircraft came from the same McDonnell Douglas widebody trijet lineage. Both lost the left number 1 engine and pylon during takeoff. Both planes became uncontrollable almost immediately. Both accidents ended in fires, deaths and loss of life on the ground.
In response, the FAA temporarily suspended the MD-11 fleet. This represented a fairly significant portion of UPS’s fleet (about 9% of its total fleet). In the weeks following Flight 2976, the airline announced the accelerated retirement of its remaining MD-11s, completing the phaseout by early 2026.
Former NTSB major accident investigator Stephen Carbone expressed concerns about oversight of heavy maintenance. warning that airlines can lose control when major maintenance jobs are outsourced. He noted the need for stricter FAA and airline oversight of third-party maintenance, repair and overhaul providers.
The parallels, the differences and the lesson
The similarities between American Airlines Flight 191 and UPS Flight 2976 are striking, but the accidents were not identical.
The 1979 accident occurred due to maintenance damage during engine removal and reinstallation. The crisis of 2025, according to the NTSB recommendations Until now, it was caused by prolonged metal fatigue in a key bearing assembly. One accident was due to a detrimental maintenance procedure. The other involved an old structural part that failed after many years of use.
Still, both accidents point to the same inconvenient truth: the engine pylon structure of these planes was a critical area where failure could quickly become catastrophic.
During the NTSB hearings, FAA technical expert Dr. Melanie Violette explained that the severity of bearing failure had been misunderstood decades earlier. At the time it was not believed to be critical to the integrity or safety of the aircraft.
That detail may turn out to be one of Louisville’s most important lessons.
Commercial aviation is much safer today than it was in 1979. Maintenance practices, inspection technology, crew training, certification standards and oversight have improved dramatically. But Flight 2976 shows that even mature aircraft designs can still contain hidden risks, especially as fleets age and airframes remain in demanding cargo service long after their passenger careers have ended.
The DC-10 and MD-11 are largely no longer in the skies, with only a few exceptions still flying. But the lessons from Chicago and Louisville will likely remain part of the security conversation for years to come.
Commercial aviation is much safer now than it was in 1979, but Flight 2976 demonstrated how quickly an old, proven design can become dangerous if a hidden structural problem is overlooked. This is especially true for cargo aircraft, which often continue to fly long after their passenger service ends and go through many demanding flight cycles.
Most lines DC-10 and MD-11 are no longer in regular service, but the problems raised by the Chicago and Louisville accidents will not soon be forgotten. Now, researchers, airlines, regulators and maintenance teams are focused on finding what was lost, understanding why, and making sure this type of failure doesn’t happen again.
The NTSB’s final report on Flight 2976 will be released in November.
