A preliminary report from US safety investigators has revealed that Boeing was aware of a defective engine component implicated in the catastrophic crash of a UPS cargo plane near Louisville, Kentucky, in November 2025, which claimed 15 lives.
Known Flaws and a Fatal Failure
The National Transportation Safety Board (NTSB) stated that the part suspected of causing the accident—a "spherical bearing race" assembly that secures engines to wings—had failed on at least four previous occasions across three separate aircraft. Despite this history, Boeing did not deem it a flight safety issue requiring urgent repair.
In a service letter issued to MD-11 owners in February 2011, Boeing advised of the earlier failures but recommended only that the part be checked during routine general inspections, typically scheduled every five years, rather than mandating immediate corrective action.
The Louisville Tragedy Unfolds
The crash occurred on 4 November 2025 shortly after the MD-11F freighter took off from Louisville Muhammad Ali International Airport. Witnesses reported seeing fire on the plane's left wing before the engine detached as the aircraft attempted to gain altitude.
The 34-year-old plane plunged into an industrial complex at approximately 5:15 pm, creating a massive fireball. The impact killed the three crew members on board and 12 people on the ground, with the final victim succumbing to injuries on Christmas Day.
Footage from local news showed multiple buildings ablaze and thick black smoke billowing over the area.
Aftermath and Mounting Scrutiny
In response to the disaster, freight carriers UPS and FedEx temporarily grounded their fleets of MD-11s, aircraft originally manufactured by McDonnell Douglas before its acquisition by Boeing. The crash has also prompted at least one lawsuit, with relatives of a ground victim alleging negligence for keeping the jet in service with known maintenance issues.
The NTSB's investigation found cracks where the engine connected to the wing. It was reported that the specific engine mount parts had last been closely examined in October 2021, with the next inspection not due for another 7,000 flight cycles.
Aviation expert and former crash investigator Jeff Guzzetti noted that a bulletin from McDonnell Douglas in 1980 had identified failures of the same bearing race as a "safety of flight condition," raising serious questions about the adequacy of Boeing's 2011 service letter and how UPS acted on the information.
Boeing offered condolences to the families affected but did not directly address the report's findings. UPS expressed profound sadness and stated its focus remained on the recovery effort.
The tragedy has drawn parallels to the 1979 crash of an American Airlines DC-10 in Chicago, which led to a global fleet grounding. The DC-10 was a predecessor to the MD-11 and shared a similar design.
