An aircraft that crashed in Kentucky in November, resulting in 15 fatalities, had a structural flaw known to Boeing for 15 years, according to a report by the U.S. National Transportation Safety Board (NTSB). The UPS MD-11F freighter crashed after one of its engines detached from the wing during takeoff preparations at Louisville. The aircraft briefly became airborne before crashing into an industrial area.

The NTSB update revealed cracks in the engine mounting assembly, a problem previously observed in other aircraft. Boeing, the manufacturer responsible for the aircraft, had concluded at the time that the issue "would not result in a safety of flight condition," according to the report.

The MD-11 is an older design originally produced by McDonnell Douglas, which Boeing acquired in 1997. Production of the MD-11 ceased in 2001, but Boeing has continued to provide parts and service support for the existing fleet. The crash raises questions about the long-term maintenance and safety oversight of aging aircraft, particularly in the air cargo sector, which has seen substantial growth in recent decades due to the expansion of e-commerce and global supply chains. The incident is likely to prompt scrutiny from aviation authorities worldwide, including the European Aviation Safety Agency (EASA) and the Civil Aviation Administration of China (CAAC), which also regulate the operation of MD-11 aircraft. The NTSB investigation is ongoing and will likely examine Boeing's initial assessment of the flaw and the subsequent maintenance protocols for the MD-11 engine mounting assembly.