Air TransportBoeing aware of MD-11F pylon bearing concerns ahead of UPS crash, says NTSB
The National Transportation Safety Board (NTSB) stated that Boeing had prior knowledge of concerns regarding the pylon spherical bearings on MD-11 aircraft before the fatal UPS Flight 2976 crash on November 2025 near Louisville’s Muhammad Ali International Airport.
The NTSB has called for a focus on inspection of the MD-11F’s spherical bearing assemblies, rather than immediate replacement. The board is reviewing how Boeing’s 2011 service letter was integrated into UPS’s maintenance program.
“The design of the accident aeroplane’s aft-mount bulkhead spherical bearing assembly is consistent with that of part number S00399-1, subject to a 2011 service letter from Boeing,” said the National Transportation Safety Board.
Boeing maintains that the bearing failure did not negatively impact aircraft safety during flight. “The review of the bearing failure found it did not pose a negative impact on aircraft safety during flight,” a Boeing spokesperson stated.
The UPS MD-11F collided with the ground shortly after takeoff, resulting in 15 fatalities, including all occupants and 12 people on the ground. Investigators found fractures in the left aft-mount bulkhead lugs, with the associated spherical bearing assembly recovered at the scene and exposed to fire.
The MD-11F fleet has been in service for more than three decades, primarily with cargo operators. Operators have relied on Boeing service communications for ongoing maintenance of critical components such as the pylon spherical bearings.
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