NTSB Links UPS MD-11 Crash to 15-Year-Old Boeing Warning

The National Transportation Safety Board (NTSB) has identified a crucial component linked to the November 4, 2025, crash of UPS Flight 2976. A three-inch (7.62 centimeters) engine mount bearing, previously flagged by Boeing nearly 15 years ago, was found to be the cause of the incident. This failure resulted in the left engine detaching from the aircraft during a routine departure from Louisville, triggering a fire and ultimately leading to the crash.

On January 14, 2026, the NTSB provided an update detailing how the mount bearing’s failure allowed the left engine and pylon assembly to separate from the wing. The investigation revealed that the housing for the aft mount bearing on the pylon of the number one engine had deteriorated. The assembly’s two lugs, which are typically bolted together, exhibited fractures, and the spherical bearing race was found split into two sections. Evidence of fatigue cracking suggested that this damage had developed over time.

The incident involving UPS Flight 2976 is notable within aviation history, marking a rare and severe failure. The McDonnell Douglas MD-11 aircraft had been operating under normal conditions when the catastrophic failure occurred.

Previous Warnings and Regulatory Actions

Boeing, which merged with McDonnell Douglas in 1997, has been aware of concerns regarding the MD-11’s pylon bearings since a series of prior incidents prompted a service bulletin from the Federal Aviation Administration (FAA). This bulletin included recommendations for five-year inspections and suggested replacing the components with a newer design. However, compliance with these recommendations was not mandatory.

The aircraft involved in the crash, registered as N259UP, did not feature the updated bearing design. Further investigation will determine whether UPS Airlines had implemented this procedure across its fleet of MD-11s or whether all necessary inspections had been performed.

The NTSB is also examining the maintenance protocols at UPS Airlines. A visual inspection of the left pylon had taken place in 2021, and the aircraft was not yet due for a more thorough inspection of the mount lugs. Investigators will need to establish why maintenance personnel failed to detect the fatigue cracking.

Implications for the MD-11 Fleet

In light of the crash, the FAA issued an emergency airworthiness directive that grounded all US-registered MD-11s pending corrective measures. As no specific corrective actions were outlined, this effectively resulted in an indefinite grounding of the fleet.

Despite the aircraft’s age, many airlines, including FedEx Express, anticipate a return to service for their MD-11 fleets soon. The findings from the NTSB investigation do not indicate that a major redesign of the pylon structure will be necessary. Should the required repairs or modifications be straightforward and cost-effective, airlines may resume operations once official directives are issued.

The investigation continues to raise critical questions about the long-term safety and maintenance of aging aircraft, particularly those like the MD-11, which has been in service for over three decades. The NTSB’s findings will be pivotal in shaping future regulations and ensuring the safety of air travel.