Boeing warned of flaw years before deadly UPS plane crash

• A UPS plane crash in Louisville involved a part that Boeing had flagged for potential issues 14 years prior.
• The NTSB found fatigue cracks on a pylon part, similar to what Boeing noted in a 2011 letter to airlines.
• The crash of UPS Flight 2976 killed 15 people after its left engine and pylon detached from the wing.

The UPS plane that crashed into an industrial site near the Louisville Muhammad Ali International Airport in November featured problems with a part that aerospace company Boeing had flagged 14 years earlier, officials with the National Transportation Safety Board stated in a report released Jan. 14.

In a February 2011 letter to airlines, Boeing noted failures with parts of the pylon, a structural component that connects the engine, during four incidents on three MD-11 airplanes, which is the same model of the UPS plane that crashed Nov. 4. After takeoff, the pylon and left engine UPS Flight 2976 detached from the wing, resulting in a catastrophic crash that killed 15 people, including the three crew members aboard the plane.

The MD-11 planes Boeing studied showed fatigue cracks on a part of the pylon known as the spherical bearing race, which allows bearings to ride back and forth during operation. NTSB investigators reported similar cracks in preliminary findings of the UPS Flight 2976 crash.

Following its initial study, Boeing said it would update its maintenance manual to include inspections to ensure the spherical bearing race would remain functional.

NTSB officials said they are still reviewing the inspection techniques used by Boeing for its MD-11 planes, how UPS incorporated the information of the Boeing letter into its own practices, and the "correspondence history between Boeing and the FAA leading up to issuance of the Service Letter and thereafter."

The update NTSB officials released Jan. 14 also included images of cracked bearings that showed signs of fatigue and overstress from UPS Flight 2976, which were taken inside the agency's materials laboratory in Washington, D.C.

The wear shown on a particular bearing officials photographed was "about 75%" attributed to fatigue, while the rest "was consistent with overstress failure." Investigators also found remnant "grease-like material" within the spherical bearing assembly.

According to its maintenance program guidelines, UPS officials are required to inspect the assembly every 72 months, and conduct a "specific, detailed inspection" of the lugs every 29,200 cycles, or when a plane takes off and lands. Records show UPS last inspected the assembly on Flight 2976 in October 2021, while the plane had accumulated 21,043 cycles following its most recent lug inspection.

A full investigatory report on the UPS crash is expected to come from the NTSB in 12-24 months.

Businesses regain full access to building within crash site

Officials have also provided more details in recent days about the efforts to clean up the debris within the crash site, a mostly industrial area just south of Louisville's airport. Crews completely cleared the area of debris by early January, though the area largely remains closed because officials continue to test the water and soil contaminated by the oil spilled from the crash.

Louisville officials allowed area businesses to have 24/7 access to their properties starting Jan. 14. Businesses can welcome in customers by escorting them through approved checkpoints.

Crews are continuing to repair water, sewage and road Infrastructure around Grade Lane. Damage to roadways caused by the plane crash will need to be fixed before the area can fully reopen, Louisville Metro Emergency Management Agency Jody Meiman said.

Reporters Olivia Evans and Matthew Glowicki contributed. Reach reporter Leo Bertucci at [email protected] or @leober2chee on X, formerly known as Twitter