WINSTON-SALEM, N.C. (AP) — A plane that crashed last month in Winston-Salem, killing two people from Illinois, made a sputtering sound and was upside down shortly before hitting the ground, according to a preliminary report published Friday by the National Transportation Safety Board.

The Piper PA30 Twin Comanche was preparing to land at Smith Reynolds Airport in Winston-Salem on Nov. 19, the report stated.

An air traffic controller cleared the pilot to land, and the pilot confirmed the radio transmission but continued past the runway, according to the report. The pilot then requested “a right 360° turn, which the controller approved. There were no further radio transmissions from the pilot.

A witness on a nearby golf course told investigators that he watched the airplane and heard it “making a sputtering sound,” the report stated.

“The witness further described that the airplane appeared to be ‘flying at a 45° angle and veering right’ as it flew overhead,” the report said. "The witness stated, ‘It flew until completely inverted upside down, then plunged out of sight, under (the) tree-line.’”

Pete Wentz, an air safety investigator with the National Transportation Safety Board, told the Winston Salem-Journal last month that the pilot reported engine trouble to the tower as he approached to land.

The plane crashed in a residential area, killing pilot Joe Kreher Jr. and his wife, Patty Kreher. They lived in Freeburg, Illinois, a suburb of St. Louis.