Boeing knew of flaw in part linked to UPS plane crash, report says

A critical structural flaw that contributed to the fatal crash of a UPS cargo plane in Kentucky had been identified by Boeing 15 years prior, according to a National Transportation Safety Board (NTSB) investigation update. The November 2025 crash occurred when an engine detached from the MD-11F freighter during takeoff from Louisville Muhammad Ali International Airport, killing 15 people including three crew members and 12 individuals on the ground.

The NTSB report details fatigue cracks in the engine mounting assembly's bearing and housing—the same component Boeing had documented failing on three other MD-11 aircraft between 2008-2011. At that time, Boeing issued a non-binding service letter recommending visual inspections every five years and noted an improved bearing assembly design, but stopped short of mandating replacements.

Former air accident investigator Tim Atkinson expressed concern about Boeing's prior assessment: "The structure carries fundamental flight loads like thrust and drag. It's extraordinary that Boeing concluded such a failure wouldn't compromise safety." The MD-11, originally designed by McDonnell Douglas before Boeing's 1997 acquisition, remains in cargo service despite production ending in 2001.

This incident revives scrutiny of Boeing's safety protocols, echoing recent controversies including the 737 MAX design flaws linked to 346 fatalities and January 2024's mid-flight door plug detachment. Boeing stated it continues to cooperate with the NTSB investigation while extending condolences to affected families. The full investigation continues with a final report pending.

Technical Context

The engine pylon assembly—which connects jet engines to wings—experiences extreme cyclical stresses during flight cycles. Fatigue cracks develop over time from repeated pressurization and vibration, requiring rigorous inspection protocols. Boeing's 2011 service letter (MM-11-047) identified specific bearing failures but deemed the risk manageable through existing maintenance procedures. Aviation regulators typically require mandatory airworthiness directives for critical flaws, raising questions about why this remained a recommendation.

Broader Implications

This case highlights challenges in legacy aircraft maintenance, where manufacturers continue supporting aging fleets decades after production ends. The NTSB's findings may prompt reevaluation of non-mandatory service bulletins for critical components industry-wide. With over 200 MD-11s still operational globally, carriers face renewed pressure to implement Boeing's optional bearing upgrade despite added costs.

Official NTSB investigation update | Boeing MD-11 Service Documentation