MONTICELLO, Iowa (AP) — Federal investigators still aren’t certain what caused a small plane to crash near an eastern Iowa airport, killing the pilot. Station KCRG reports that the final National Transportation Safety Board report says the plane was in good working order before crashing in June 2017. The single-engine aircraft came down in a cornfield near Monticello Regional Airport.

The report says 90-year-old Jerry Naylor died in the crash. He lived in Scotch Grove. He was the only person on board.