Frame by frame, six photos released by federal investigators graphically captured horrifying images of the UPS plane turning into a fireball.

The cargo plane was taking off from Louisville earlier this month when it crashed moments after becoming airborne, killing the three crew members and 11 people on the ground.

The National Transportation Safety Board said on Thursday it has found evidence of fatigue cracks in a key part of a UPS MD-11 cargo jet that crashed this month in Kentucky, an important clue into the cause of the incident that killed 14.

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 airliner involved. MD-11 planes have