A UPS plane crashed in Louisville. This happened last November. A broken engine part caused the crash. The NTSB found this.
The NTSB looked at the engine. They saw cracks in a metal part. The part held the engine. The cracks came from old wear. This made one engine fall off. The plane crashed after it took off.
Three people on the plane died. Twelve people on the ground also died. The NTSB said the falling engine caused the crash.
Boeing made the plane. Boeing had a similar problem before. Fifteen years ago, Boeing knew this part could break. They told plane owners to check it. They also had a new part.
But Boeing thought it was not a big problem. The NTSB report says the cracks got bigger. The part became weak. Boeing's old letter did not stop the crash.
This is important news. It will make people check Boeing's safety checks. It will also ask if Boeing's fixes were good. This crash shows we must check planes well.