VICTORIA, Minn. (AP) — Crucial pieces of a single-engine plane piloted by a Nebraska surgeon apparently fell off in flight before it crashed west of Minneapolis, killing him and two relatives, investigators say.

The Mooney M20M crashed and burned late Saturday afternoon near a home about a block away from the downtown area of Victoria, a community of about 7,300 people, about 25 miles west of Minneapolis. The flames scorched the house but nobody on the ground was injured.

Relatives and employers identified those who died as Dr. James Edney, 72, of Omaha, Nebraska, who was piloting the plane, his stepson, Jacob Mertes, 42, and Jacob’s wife, Dr. Sara Mertes, 37, both of Libby, Montana.

National Transportation Safety Board investigator Mike Folkerts told reporters Sunday that the plane, which had taken off from Alexandria in western Minnesota, was approaching Flying Cloud Airport in suburban Eden Prairie when it crashed.

“The pilot contacted the control tower, then made several heading changes and altitude deviations from a normal, stable flight path while on final,” Folkerts said. “The last transmission was about 10 miles from the airport.”

He said the contact with the control tower was routine, and no distress call was made.

But Folkerts said some parts from the plane’s tail — pieces of the left elevator and left horizontal stabilizer — were found a couple blocks from the rest of the wreckage, indicating they fell off in flight.

“Without an elevator and a horizontal stabilizer, the aircraft is not flyable,” he said.

The sky was overcast with a 1,100-foot ceiling, and 9 miles visibility, he said.

Folkerts said the NTSB is looking into all factors that could have caused the crash, including the pilot, the aircraft and the environment. A preliminary investigative report is expected in about two weeks; a full report takes 12 to 18 months.