Elizabeth Isham Cory, a spokeswoman for the FAA, said Flight 97 left Saturday from Minneapolis-St. Paul International airport bound for Honolulu. The flight crew didn't notice that the engine part — part of what's called a thrust reverser — was missing until the DC-10 had landed, she said.

No one was injured. The thrust reverser helps to slow planes when they come in for a landing. The landing in Hawai'i was routine, Isham Cory said. She referred to the engine part that fell, which is located on the tail of the aircraft, as an "extra mechanism."

The Dakota County sheriff notified the FAA after a resident who saw the piece fall to the ground called Inver Grove Heights police, she said. The FAA later retrieved the engine part, which weighed about 200 pounds.

Sgt. Greg Olson of the Inver Grove Heights Police Department said the engine part landed about the length of a football field from a home in a developing area. An anonymous caller notified police around 3:45 p.m., he said.

Inver Grove Heights is located just a few miles to the east of the airport. Olson said he believes jets were taking off in that direction Saturday and flying over the city.

"This is very rare," Isham Cory said. "We are trying to decide how it happened, why it happened and what steps can be taken to prevent it from happening on another plane."

She said the investigation would take several weeks.