According to a new report published on Wednesday by the National Transportation Safety Board, a crucial engine-mount component that failed on a UPS cargo plane during a fatal crash in Louisville last year had a known history of fractures dating back more than ten years. The NTSB said Boeing docu mented at least four prior failures of the same engine-mount bearing assembly on three different MD-11 aircraft in a 2011 service letter, but concluded at the time that the defect “would not result in a safety of flight condition.” The UPS MD-11F crashed on November 4, 2025, just after it took off from Louisville Muhammad Ali International Airport on its way to Hawaii. According to investigators, during takeoff, the aircraft’s left engine caught fire and broke away from the wing. Three crew members and twelve people on the ground were killed when the aircraft crashed into several buildings close to the airport. Later, injuries sustained in the crash claimed the life of the fifteenth victim. Known flaw, limited response The NTSB reports that overstress failure and fatigue cracking were discovered throughout the spherical bearing race, a crucial part that holds the engine to the wing. According to the agency, Boeing was aware that a recessed groove in the design could cause the part to fracture due to fatigue; this issue was addressed in the 2011 service letter. In addition to pointing to an updated design without the groove where cracks may start, that letter advised operators to visually inspect the part every 60 months. However, Boeing concluded that the failures did not constitute a flight safety hazard, and installation of the older design was not forbidden. According to UPS policy, inspections were required every 72 months. According to records, the part was last visually inspected in October 2021, which was approximately four years before the collision. It was also lubricated two weeks before the collision. What investigators are now examining The NTSB said it is now reviewing: How Boeing’s inspection guidance was incorporated into airline maintenance programs Whether UPS fully adopted and followed the service letter recommendations What communications occurred between Boeing and the Federal Aviation Administration before and after the 2011 notice The FAA temporarily banned MD-11 and related DC-10 aircraft after the crash, citing the possibility that engine detachment could result in loss of control. UPS and FedEx also grounded their MD-11 fleets. Boeing response In a statement, Boeing said it supports the NTSB’s investigation and offered condolences to the victims’ families, but did not directly address the findings. The company has faced increased scrutiny in recent years over quality control and safety oversight. The MD-11, which was built by McDonnell Douglas prior to Boeing purchasing it in the 1990s, has long since been retired from passenger service but is still used by cargo carriers. While the investigation is ongoing, all of the remaining MD-11s and a number of related aircraft are still grounded. The NTSB has not yet determined a probable cause of the crash. Several lawsuits against UPS, Boeing, and engine manufacturer General Electric are pending. The post Boeing Knew Of Engine-Mount Flaws Years Before Fatal UPS Plane Crash In Louisville, NTSB Says appeared first on LEO Weekly | Louisville Eccentric Observer. ...read more read less