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, killing the three crew members and 12 people on the ground.

The NTSB's update report revealed that cracks were discovered in the engine mounting assembly, a problem previously observed in other aircraft of the same model. Boeing, the manufacturer responsible for the aircraft, had concluded at the time of the initial discovery that the issue "would not result in a safety of flight condition."

The MD-11 is a tri-jet wide-body airliner, originally designed and produced by McDonnell Douglas. Boeing acquired McDonnell Douglas in 1997, inheriting the MD-11 program. Production of the MD-11 ceased in 2001, but Boeing has continued to provide parts and service support for the existing fleet. The MD-11, while no longer in production, remains a workhorse for cargo carriers globally, particularly on long-haul routes where its payload capacity and range are advantageous.

The crash has raised concerns about the continued airworthiness of older aircraft and the adequacy of maintenance and inspection protocols. The incident also highlights the challenges faced by manufacturers in supporting aircraft that are no longer in production, ensuring that potential safety issues are addressed proactively. The NTSB investigation is ongoing, and further updates are expected as investigators delve deeper into the circumstances surrounding the engine separation and the effectiveness of Boeing's response to the known structural flaw. The findings of the investigation could have implications for the operation and maintenance of other aging aircraft in service worldwide.