NTSB: Boeing 2011 MD‑11 Engine‑Mount Warning Downplayed 'Safety of Flight' Risk Before Deadly UPS Louisville Crash
The NTSB’s new report says Boeing’s 2011 service letter downplayed MD‑11 engine‑mount spherical bearing‑race fractures as not a “safety of flight” issue even though the same component had fractured at least four times on three aircraft and McDonnell Douglas had earlier labeled similar failures a safety‑of‑flight condition; the bearing in the Nov. 4, 2025 UPS MD‑11 was found broken in two pieces with cracked mounting lugs. The freighter lost its left engine during takeoff from Louisville at about 200 mph, killing three crew and 12 people on the ground and destroying a business complex, and while the NTSB has not yet issued a probable cause it says cracks in the left‑engine mounting assembly “may have contributed”; Boeing issued only a brief statement supporting the investigation, and the FAA did not issue an airworthiness directive after Boeing’s 2011 bulletin.
📌 Key Facts
- NTSB’s new report cites Boeing’s 2011 service letter, which stated MD‑11 engine‑mount fractures "would not result in a safety of flight condition."
- The MD‑11 engine‑mount spherical bearing race had fractured in at least four prior incidents across three aircraft, a history documented in Boeing’s 2011 letter and cited by the NTSB.
- McDonnell Douglas’s 1980 bulletin — issued after the 1979 American Airlines DC‑10 crash — had identified the same spherical bearing race failures as a "safety of flight condition," raising questions about why Boeing’s 2011 language was downgraded.
- Experts say the 2011 bulletin allowed operators to install older, failure‑prone bearings instead of requiring the redesigned part, and the FAA did not follow up with an airworthiness directive.
- The UPS MD‑11 freighter lost its left engine during takeoff from Louisville on Nov. 4, 2025, at about 200 mph; the crash killed three pilots and 12 people on the ground and destroyed a business complex.
- The NTSB has not yet issued an official probable cause but said cracks in the left‑engine mounting assembly "may have contributed" to the crash.
- Investigators found the failed bearing race broken in two pieces with cracked mounting lugs; the last detailed inspection of the mount was in October 2021, with roughly 7,000 cycles remaining before the next scheduled inspection.
- Boeing issued a brief statement saying it supports the NTSB investigation and offers condolences but did not address the substance of the report’s findings.
📰 Source Timeline (4)
Follow how coverage of this story developed over time
- Confirms the Nov. 4, 2025 UPS MD‑11 freighter lost its left engine during takeoff from Louisville at about 200 mph, killing three pilots and 12 people on the ground and destroying a business complex.
- Details that Boeing’s 2011 service letter documented four earlier failures of the MD‑11 engine‑mount spherical bearing race on three aircraft but 'determined it would not result in a safety of flight condition.'
- Notes that McDonnell Douglas in a 1980 bulletin, after the 1979 American Airlines DC‑10 crash, had identified the same spherical bearing race failures as a 'safety of flight condition,' raising questions about why Boeing downgraded that language in 2011.
- Adds expert criticism that the 2011 bulletin allowed operators to install older, failure‑prone bearings instead of requiring the redesigned part, and that FAA never followed up with an airworthiness directive.
- Specifies that the failed bearing race was found broken in two pieces and its mounting lugs were cracked, and that the last detailed inspection of the mount was in October 2021 with roughly 7,000 cycles left before the next scheduled inspection.
- NTSB’s new report squarely cites Boeing’s 2011 service letter and highlights Boeing’s statement that MD‑11 engine‑mount fractures 'would not result in a safety of flight condition.'
- The article reiterates that the same component had fractured in at least four prior incidents across three different aircraft before the Louisville crash.
- It confirms the NTSB has not yet issued an official probable cause but says cracks in the left‑engine mounting assembly 'may have contributed' to the November 4, 2025 crash.
- Boeing issued a brief statement saying it supports the NTSB investigation and offers condolences, but did not address the substance of the report’s findings.