Engine Failure Triggered by Metal Fatigue
Federal investigators have determined that metal fatigue was the primary cause of the devastating UPS cargo plane crash near Louisville, Kentucky, which claimed 14 lives. A preliminary report from the National Transportation Safety Board (NTSB) reveals that fatigue cracks were discovered in the hardware connecting the aircraft's left engine to its wing.
The Fatal Sequence of Events
The incident occurred on November 4 as the 34-year-old McDonnell Douglas MD-11 was accelerating for takeoff from Louisville Muhammad Ali International Airport, bound for Hawaii. According to the report, the General Electric engine detached from the plane's left pylon during the takeoff roll.
As the engine separated, it "traversed above the fuselage and subsequently impacted the ground," immediately igniting a fire. Simultaneously, another blaze started near the left pylon attachment point. Despite the left side of the aircraft being consumed by flames, the plane managed to clear the airport's perimeter fence but never climbed more than 30 feet above the ground.
One witness in the air traffic control tower reported that the aircraft appeared to be at the proper takeoff speed but was unable to climb properly. Another witness observed the plane stop climbing, lose altitude, and then roll "slightly to the left" before crashing into a storage yard and two buildings, including a petroleum recycling facility.
Maintenance and Inspection Timeline Under Scrutiny
The investigation has raised serious questions about aircraft maintenance schedules. The NTSB confirmed that UPS had last inspected the engine mount in 2021, and it wasn't scheduled for another inspection until the plane completed an additional 7,000 flights. A visual inspection of the left pylon was conducted by UPS maintenance crews just seven days before the crash on October 28.
Former federal crash investigator Jeff Guzzetti commented to The Associated Press: "It appears UPS was conducting this maintenance within the required time frame, but I'm sure the FAA is now going to ponder whether that time frame is adequate."
Aviation expert John Cox described fatigue cracks as "normal wear and tear on an aircraft," explaining that metal parts subjected to constant vibration will eventually develop cracks. The critical question becomes how frequently these components require inspection and what maintenance protocols are necessary.
However, attorney Robert Clifford, who has represented families in airline crashes for 45 years, offered a different perspective: "The NTSB's findings suggest the aircraft was 'old, tired and well beyond its useful life.' Metal fatigue can happen over time and should be detected upon proper safety investigations and inspections."
Industry-Wide Implications and Historical Parallels
Following the tragedy, the Federal Aviation Administration issued an Emergency Airworthiness Directive grounding all MD-11 aircraft until they could be individually inspected and repaired. This directive was later expanded to include nine additional similar aircraft models on November 14.
The NTSB report noted similarities to the 1979 American Airlines DC-10 crash in Chicago that killed 273 people, where the left engine and pylon assembly also separated from the aircraft. However, investigators emphasized that the maintenance circumstances differed between the two incidents.
Bill Moore, president of UPS Airlines, has acknowledged that returning the MD-11 fleet to service is "not going to happen quickly." MD-11 aircraft constitute approximately nine percent of the UPS fleet and four percent of the FedEx fleet, presenting significant operational challenges for both companies.
Former federal crash investigator Alan Diehl has called for the FAA to reevaluate maintenance schedules and consider advanced inspection technologies beyond visual examinations, stating: "It is clear that engine pylon attachment failures are these aircraft's Achilles' heels."
A final report from the NTSB is expected approximately one year after the accident, while the community continues to mourn the loss of three crew members and eleven people on the ground, with twenty-three others injured in the catastrophic event.
