The fiery crash of a UPS plane shortly after its left engine flew off its wing and sparked a massive fire during takeoff could spell the end of the 109 remaining MD-11 airliners that have been exclusively hauling cargo for more than a decade.

NTSB investigators "found evidence of fatigue cracks in addition to areas of overstress failure."

The National Transportation Safety Board unveiled new details describing a stunning frame-by-frame images showing the left engine separating from the plane and going up and over the wing, after the fiery crash of a UPS plane in Louisville killed 14 people earlier this month and left a half-mile long debris field.

Worn connecting hardware likely caused the left engine to detach from a UPS cargo plane that crashed in Louisville, Ky., the NTSB said.