Federal investigators have revealed that Boeing was aware of a defective aircraft part more than a decade before it contributed to a catastrophic UPS cargo plane crash in Kentucky last year, which claimed 15 lives.
A Known History of Failure
The National Transportation Safety Board (NTSB) stated on Wednesday, 14 January 2026, that Boeing had documented four separate failures of a critical spherical bearing race on three different MD-11 aircraft as far back as 2011. This component is vital for securing an engine to the wing.
Following these incidents, Boeing issued a warning to aircraft owners about the flaw. However, the planemaker determined at the time that it would not result in a safety of flight condition. The NTSB did not clarify whether any further failures were recorded after 2011.
The Louisville Disaster
The relevance of that 2011 warning became tragically clear on 4 November 2025. A 34-year-old UPS MD-11 freighter, registration number N276UP, had just taken off from Louisville's Muhammad Ali International Airport bound for Hawaii.
As it rolled down the runway, the left engine tore away from the wing. NTSB photos show flames erupting as the rear of the engine began to detach before it flew up and over the wing, which was then engulfed in fire.
The stricken aircraft managed to climb only 30 feet (9.1 metres) before crashing into several industrial buildings beyond the runway, creating a massive fireball visible for miles. All three pilots on board and 12 people on the ground were killed.
Missed Cracks and a Grim Echo
Investigators later found cracks in parts of the engine mounting pylon. These cracks had not been detected during routine maintenance. The last detailed inspection of these crucial components was in October 2021, and the plane was not scheduled for another such check for approximately 7,000 more flight cycles.
The crash has chilling echoes of the 1979 American Airlines DC-10 disaster in Chicago, which killed 273 people after an engine separated on takeoff. The DC-10 was the predecessor to the MD-11. While that earlier tragedy was blamed on maintenance error, it led to the global grounding of the DC-10 fleet.
In the wake of the Louisville crash, all remaining MD-11s and 10 related DC-10s still in service with cargo carriers like UPS and FedEx have been grounded indefinitely.
