The National Transportation Safety Board’s proceedings in Washington, D.C., this week are the first public accounting of how a UPS cargo jet’s engine came to tear off its wing during a routine departure — and why a known flaw in the aircraft’s design went uncorrected until 15 people were dead. The agency, which has spent six months investigating the crash, used the two-day hearing to release thousands of pages of evidence and to press officials from the airline, the manufacturer, and the government on why a pattern of cracked engine-mount components did not trigger earlier action.
The accident occurred on November 15, 2025, when the McDonnell Douglas MD-11, loaded with cargo, began its takeoff roll at Louisville’s Muhammad Ali International Airport. As the aircraft accelerated, the left engine separated from the wing and the plane crashed, killing the three-member flight crew and a dozen people on the ground. Another 23 people were injured. It was the deadliest aviation disaster in the United States in several years and the only fatal crash involving an MD-11 since a separate engine-separation accident decades earlier.
Within days of the crash, NTSB investigators identified cracking in the engine-mount assembly — the structural components that attach the engine to the wing. That finding alone pointed to a mechanical failure, but the investigation deepened when the agency pulled maintenance records from the aircraft’s service history. Those records, according to the AP, showed that similar cracks had been identified during routine inspections of the wings of at least 10 other MD-11 airframes operated by multiple carriers.
Most of those crack findings, the NTSB said, were never forwarded to the Federal Aviation Administration, the agency responsible for ordering safety fixes. The FAA’s own rules require airlines and repair stations to report certain failures, malfunctions, and defects, but the cracks in the engine mount fittings were not classified as reportable under the existing maintenance guidance. The result, the board’s investigators suggested, was a blind spot: multiple aircraft with the same defect flying in commercial service, with neither the regulator nor the manufacturer tracking the trend.
The hearings, which ran Tuesday and Wednesday, put NTSB board members and staff face-to-face with representatives from UPS, Boeing (which inherited the MD-11 design through its 1997 merger with McDonnell Douglas), and the FAA. The focus was on the gap between what maintenance crews were seeing and what the broader safety system was recording. Investigators sought to understand why the cracked fittings — which could be caught during scheduled checks — did not prompt a fleet-wide inspection or an airworthiness directive.
The 2,058 pages of documents released alongside the testimony include metallurgical analyses of the failed parts, maintenance logs from UPS and other operators, and correspondence between the company, Boeing, and regulators. The NTSB does not plan to issue its final report and probable-cause determination until later this year, but the hearing record often previews the central safety recommendations. In past accident investigations, the board has used such hearings to publicly pressure manufacturers and the FAA to act before the final report is complete.
The MD-11, a long-range tri-jet introduced in the early 1990s, has a limited commercial role today; most passenger airlines have retired the model, but cargo carriers including UPS and FedEx continue flying it because of its payload capacity and availability on the secondary market. The engine-mount cracking issue, if it extends across the remaining fleet of several hundred aircraft, could have significant cost and operational implications for cargo operators. The NTSB’s inquiry may also raise larger questions about how the FAA collects and analyzes service-difficulty data from an aging cargo fleet that operates under different oversight rules than passenger aircraft.
For families of the 15 victims and for the Louisville community where the crash occurred, the hearing represented a step toward accountability. The NTSB has emphasized that the investigation will determine not just the mechanical cause of the engine separation, but the sequence of decisions — by mechanics, by engineers, by managers, and by regulators — that allowed a known structural problem to persist until it claimed lives.