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UPS said it relied on Boeing’s assessment that a known engine mount issue did not pose a flight safety risk when it chose not to adopt enhanced inspections before last year’s fatal cargo plane crash in Louisville, according to newly released National Transportation Safety Board filings.
In its post-hearing submission to the NTSB, UPS said it followed all required Boeing and Federal Aviation Administration-approved maintenance programs for its MD-11 fleet.
The company said Boeing’s 2008 and 2011 service letters described the issue as not a “safety of flight” condition and stated that existing inspection intervals were sufficient to identify problems involving the engine mount’s spherical bearings.
UPS Flight 2976, a McDonnell Douglas MD-11 cargo jet bound for Honolulu, crashed shortly after takeoff from Louisville Muhammad Ali International Airport on Nov. 4, 2025, after its left engine and pylon separated from the aircraft.
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Three crew members and 12 people on the ground were killed, while 23 others were injured. The NTSB has not yet released its final report on the accident.
UPS said it reviewed Boeing’s service letters and incorporated revisions to the aircraft maintenance manual, but did not alter its maintenance program. They said this was because Boeing also concluded the issue was not safety-related and never updated its Maintenance Planning Document (MPD), which operators use to establish required maintenance schedules.
According to UPS, Boeing’s failure to revise the MPD indicated that no additional maintenance tasks were necessary beyond those already being performed.
Boeing, in its own filing with investigators, said it reviewed an operator report involving a failed spherical bearing in 2008 and determined, based on the information available at the time, that the issue was not a safety concern.
The company said it issued a service letter recommending enhanced inspections of the bearing and later revised the aircraft maintenance manual to include an inspection procedure designed to detect bearing movement.
Boeing also said aircraft operators are responsible for maintaining their fleets in coordination with regulators, noting that its maintenance planning documents and manuals provide recommendations that operators use to develop their own maintenance programs.
UPS also argued that Boeing’s Continued Operational Safety process failed to identify the damaged bearing and related structural damage as a flight safety issue. The carrier said maintenance records for the aircraft showed no evidence that the spherical bearing had migrated before the crash and argued testimony during the NTSB hearing established that bearings could fail without visible movement.
Both Boeing and UPS said in their NTSB submissions that they will continue cooperating with the investigation. Boeing said it has since worked with the FAA on updated inspection and maintenance procedures, developed a redesigned spherical bearing with a 4,000-flight-cycle life limit and implemented changes to its continued operational safety process.
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The FAA’s submission to investigators reiterated that the agency is supporting the NTSB’s investigation. The NTSB has not announced when it expects to issue its final report determining the probable cause of the crash.
FOX Business has reached out to UPS and Boeing for additional comment on their NTSB submissions.
