NTSB: Broken Part in Deadly UPS MD-11 Crash Was Documented in 2011

The National Transportation Safety Board (NTSB) released a critical update on the UPS MD-11 crash investigation. The accident occurred on November 4, 2025, in Louisville, Kentucky. The cargo jet, operating as UPS Flight 2976, crashed shortly after takeoff. All three pilots were killed, along with 11 to 12 people on the ground near Louisville Muhammad Ali International Airport (SDF).

Investigators are focusing on a failed part that secured the left engine to the wing. The left engine and pylon separated from the wing shortly after the aircraft rotated. This separation caused the plane to crash into industrial buildings.

Spherical Bearing Race Cracks Identified

The NTSB found evidence of fatigue cracking in a key component. This part is the spherical bearing race from the left pylon aft mount bulkhead. The bearing race fractured into two pieces. Fatigue cracking covered about 75% of the fractured surface. The cracks originated at a design recess groove on the bearing's interior surface. The remaining fracture area showed overstress failure.

Prior Knowledge and Manufacturer Warnings

This failure mode was not entirely new to the aircraft type. The MD-11 was built by McDonnell Douglas, which Boeing later acquired. In 2011, Boeing issued Service Letter MD-11-SL-54-104-A. This Boeing service bulletin 2011 informed operators of four previous bearing race failures. These failures, on three different MD-11 aircraft, also started at the recess groove.

Despite the documented failures, Boeing determined the issue “would not result in a safety of flight condition”. The service letter recommended a new part design that eliminated the flawed recess groove. However, it did not prohibit the installation of the older part. The letter also updated the maintenance manual to include a visual inspection of the part. This inspection was typically done every 60 months.

Questions on Maintenance Adequacy

Investigators are now questioning the adequacy of maintenance schedule for the MD-11 fleet. The accident aircraft's pylon aft mount was last inspected in October 2021. The next detailed inspection was not due for approximately 7,000 more flight cycles. This raises serious questions about the effectiveness of the visual inspection requirement.

Regulatory Response and Industry Impact

Following the crash, the FAA took immediate action. The agency issued an Emergency Airworthiness Directive (AD 2025-23-51). This AD effectively grounded all MD-11 and DC-10 aircraft worldwide. The planes cannot fly until they are inspected and necessary corrective actions are completed.

This grounding has created significant cargo plane safety concerns. The MD-11 is primarily used by cargo carriers like UPS and FedEx Express. The grounding has impacted global supply chains, especially during the peak shipping season. The EASA and other global regulators are monitoring the situation closely.

This accident is a stark reminder of the 1979 American Airlines DC-10 crash. That incident also involved engine separation and led to a temporary grounding of the DC-10, the MD-11's predecessor. The NTSB's final report will provide the ultimate conclusion. The findings will determine if the maintenance program was sufficient for this aging fleet. For more commercial aviation news, visit flying.flights.

• The MD-11 fleet remains grounded globally under an FAA Emergency AD.
• The spherical bearing's fatigue cracking began at a known design flaw.
• The NTSB is scrutinizing the 2011 service letter that deemed the issue not a "safety of flight condition".