NTSB Reveals Broken Part in Fatal UPS MD-11 Crash Failed Four Times Before

The National Transportation Safety Board (NTSB) released a factual report on the fatal UPS MD-11 crash.

This update focuses on a critical part failure. The left engine separated shortly after takeoff. This event occurred in November 2025 in Louisville, Kentucky. The plane was departing Louisville’s Muhammad Ali International Airport.

Investigators are focused on a key aircraft engine mount component. This part helps secure the MD-11’s engine to the wing. Its failure led to the catastrophic engine separation failure.

The Engine Mount Failure

The NTSB found the part broken into two pieces. The component is called the spherical bearing race. It is housed in the pylon aft mount bulkhead. Investigators found evidence of fatigue cracking in the bearing race. The lugs holding the part were also cracked. Metallurgical analysis showed fatigue accounted for 75% of the fracture. The rest was consistent with overstress failure. The 34-year-old MD-11 only reached 30 feet of altitude. It then crashed into industrial buildings. Three pilots and 12 people on the ground were killed.

Maintenance Schedule Adequacy Questioned

Cracks in the engine mount parts went undetected. They were not caught during regular maintenance. The last detailed inspection was in October 2021. The plane was not due for another check. It still had roughly 7,000 cycles remaining. This raises questions about the maintenance schedule adequacy. Aviation safety experts are reviewing the inspection intervals.

History of Warnings and Service Letters

The NTSB factual report detailed a significant history. Boeing, which bought McDonnell Douglas, knew of the issue. The manufacturer documented four prior failures of the same part. These failures occurred on three different MD-11 planes. This information was included in a 2011 Boeing service letter.

At that time, Boeing did not believe the failure threatened safety. The company “determined it would not result in a safety of flight condition.” The service letter recommended a visual inspection. It also suggested installing a redesigned part. However, it did not require these actions.

The DC-10 Precedent

This finding contrasts with earlier regulatory action. The MD-11 is the successor to the McDonnell Douglas DC-10. The crash is reminiscent of a 1979 DC-10 accident. That crash also involved a left engine separation. It led to 273 fatalities and a worldwide grounding of the DC-10 fleet.

Former FAA and NTSB investigator Jeff Guzzetti commented on the issue. He noted a 1980 McDonnell Douglas service bulletin. That bulletin did identify the spherical bearing race failure as a “safety of flight condition.” Guzzetti stated this raises questions. It concerns the severity of the 2011 Boeing warning. It also questions how UPS acted on that information.

Regulatory and Fleet Impact

Following the crash, the FAA acted swiftly. It issued an FAA Emergency Airworthiness Directive. This directive grounded all MD-11s and related DC-10s. This grounding affects major cargo carriers. The investigation is ongoing. The ultimate conclusion will come in the NTSB’s final report. This report is expected more than a year after the crash.

• Key Focus: Investigators are analyzing the failure of the bearing. They are also reviewing the maintenance history.
• Industry Response: Boeing, UPS, and the FAA declined comment on the report. They cited the ongoing NTSB investigation. Both the manufacturer and the airline expressed condolences. UPS spokesperson Jim Mayer said the company remains “profoundly saddened.” They are focused on the recovery effort.

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