U.S. NTSB releases frame-by-frame images of engine separating during deadly UPS crash in Louisville

The fire in the area of the left pylon attachment to the wing continued as the airplane cleared the blast fence. (UPS/NTSB via CNN Newsource)

A critical mount that kept the left engine attached to the UPS flight that crashed in Louisville earlier this month failed only moments after the doomed flight broke ground, according to a new report from the U.S. National Transportation Safety Board

The report includes stunning frame-by-frame photos of the left engine of three-engined McDonnell Douglas MD-11F separating from the plane and going up and over the wing and igniting a fireball seen in a sequence of six extraordinary new images obtained by investigators.

The three pilots of UPS flight 2976 and 11 people on the ground were killed when the beleaguered jet sliced a half-mile long debris field across a petroleum recycling facility and UPS warehouse, setting off a massive blaze of fire and black smoke visible for miles.

The report highlights fatigue cracks found in the hardware attaching the engine to the wing and symptoms of over-stressing, but more is still to come as the agency conducts its full investigation.

The UPS freighter was a 34-year-old jet and had been in the process of being phased out by the cargo carrier.

The Federal Aviation Administration ultimately grounded all MD-11 and MD-11F aircraft until each underwent a thorough inspection. UPS has 26 other MD-11s in their fleet, a company spokesperson told CNN.

The engine and other faulty parts

Investigators who combed the runway shortly after the crash said they recovered and cleaned hardware from the scene—a pair structural fittings which kept the engine pylon snug to the wing. The fittings—known as lugs—showed signs of fatigue cracking and over-stressing, evidenced by “their 2 o’clock and 9 o’clock positions,” investigators said.

The report also lays out a new timeline of the crash sequence along with new data which showed the plane failed to climb higher than 30 feet above Runway 17 Right at Louisville Muhammad Ali International Airport.

A witness in the control tower reported the takeoff speed appeared normal for the type of aircraft, but the climb was not. Another witness said the plane stopped climbing and began to lose altitude before rolling to the left, the preliminary report said.

The MD-11 is equipped with three engines: one on each wing and one on the tail. The plane went through some previous maintenance in San Antonio that put it out of commission for six weeks, investigators said. All service records will be reviewed.

The left and right engines of the plane are attached to the underside of pylons that are attached to each wing.

Investigators are still gathering more information

The cockpit voice recorders and the engine and pylon that fell off the airplane’s wing have also been moved to a secure facility, where they are being examined, NTSB investigators said.

The cockpit voice recorder contained two hours and four minutes of “good quality digitally recorded audio,” Inman previously said. The flight data recorder contained 63 hours of data that spanned over 24 flights, including the accident, the NTSB said.

In a rare move, the NTSB drew a parallel to a previous disaster—the 1979 crash of American Airlines Flight 191, in Chicago which killed 271 on board and two on the ground. The plane involved was a McDonnell Douglas DC-10, the forerunner to the MD-11.

During that plane’s takeoff rotation, the left engine, pylon assembly and about three feet of the leading edge of the left wing separated from the plane and fell onto the runway. The plane rolled to the left and crashed.

Multiple specialists in varying factors were deployed to investigate including experts in air traffic control, human performance, aircraft performance and more.

Notably, the 12-pages of new findings were published just more than two weeks since the November 4 crash, significantly faster than the NTSB’s typical 30-day timeline to put out a preliminary report.

“We appreciate the National Transportation Safety Board’s prompt release of preliminary findings and will fully support the investigation through its conclusion,” UPS said in a statement.

Boeing, which long ago merged with the planes original manufacturer, McDonnell Douglas, said, “We continue to support the investigation led by the NTSB. Our deepest condolences go out to the families who lost loved ones and our thoughts remain with all those affected.”

A final report from the NTSB is expected in 18 to 24 months detailing the probable causes of the crash. The agency does not place blame, but gives further recommendations to improve safety.

CNN’s Lauren Mascarenhas, Chris Isidore, Alaa Elassar, Devon M. Sayers and Aaron Cooper contributed to this report.

By Alexandra Skores, Pete Muntean, CNN