NTSB presses Boeing on pylon

The National Transportation Safety Board used the second and final day of a May 19-20 hearing to drill into how Boeing designed the MD-11’s engine pylon and how the Federal Aviation Administration oversaw that design after earlier warning signs emerged. The hearing centers on UPS Flight 2976, which crashed shortly after takeoff from Louisville Muhammad Ali International Airport on November 4, 2025. The NTSB says the Boeing MD-11F lost its left engine and left pylon before impact. Three crewmembers and 11 people on the ground were killed, and 23 others on the ground were injured. ### What exactly is the part investigators focused on? The pylon is the structure that connects the engine to the wing, and NTSB questioning on May 20 focused on the attachment system inside that assembly, including the lugs and spherical bearings tied to the engine mount. Local coverage of the hearing said investigators pressed Boeing and the FAA on the design of the failed part that preceded the Louisville crash. (ntsb.gov) Boeing testimony described the MD-11 lugs as “fail-safe,” meaning one lug should be able to carry the load if the other fails. But hearing testimony said both the forward and aft lug failed at the same time in the UPS accident sequence, drawing questions from NTSB member John DeLeeuw about how that standard was defined and tested. ### Why did the hearing keep coming back to spherical bearings? (wdrb.com) Investigators said the spherical bearing was a critical part of the pylon attachment system but was not originally treated as a principal structural element, a classification that would have required more frequent inspection. That became a central issue because cracks in related parts had been found on other aircraft before the Louisville crash. (flyingmag.com) Associated Press reported that investigators identified records of 10 earlier flaws in similar parts that help secure engines to wings on related aircraft, and that most were never reported to the FAA. UPS official David Springer told the hearing that Boeing service letters made the bearing issue “sound almost benign” and did not describe the collateral damage that could be done to the lugs attaching the engine to the wing. (flyingmag.com) ### What did Boeing say about the original MD-11 design standard? Boeing officials said during the hearing that the original certification basis did not include a structural requirement to ensure the pylon could never separate from the wing, because complete pylon separation was not considered in the design scenario they were working to protect against. Testimony described the design emphasis instead as maintaining structural integrity in a gear-up or off-airport landing and preventing fuel spillage. (nbcchicago.com) That line of questioning put the FAA in the frame as well, because the agency was one of the parties to the NTSB investigation and was questioned alongside Boeing, UPS and other participants. The NTSB’s hearing notice listed the FAA, UPS, Boeing, the Independent Pilots Association, GE Aerospace, the Teamsters Airline Division and Collins Aerospace among the parties. ### How much of the crash sequence is already established? (flyingmag.com) The NTSB’s investigation page says UPS Flight 2976, a Boeing MD-11F registered as N259UP, departed Louisville for Honolulu under Part 121 cargo rules and crashed shortly after takeoff from runway 17R at about 5:14 p.m. Eastern time on November 4, 2025. Hearing coverage said the engine separated from the left wing as the aircraft accelerated down the runway. (ntsb.gov) Day-one hearing coverage also reported that UPS switched airplanes hours before departure after a preflight inspection found a fuel leak on the originally loaded aircraft. Investigators released more than 2,000 pages of documents as the Washington hearing opened. ### What happens after this hearing? The NTSB said the May 19-20 proceeding was an investigative fact-gathering hearing, not a final determination of probable cause. (ntsb.gov) Chair Jennifer Homendy’s agency said the purpose was to obtain information needed to determine the facts and circumstances of the accident, and the hearing docket has been posted under investigation number DCA26MA024. (nbcchicago.com) The final report is likely to take more than a year from the November 2025 crash, according to Associated Press reporting carried by NBC Chicago. Until then, the May hearing record, witness testimony and docket materials will form part of the evidence base for the board’s eventual findings and any safety recommendations. (nbcchicago.com) (ntsb.gov)