SEILING, Okla. (AP) — A crop duster pilot was killed when his single-engine aircraft crashed in northwestern Oklahoma, according to the Oklahoma Highway Patrol.

Isaac Regier Jr., 65, died in the crash Monday and was the only person on board the airplane, according to an OHP report.

The plane crashed near Seiling, about 90 miles (145 kilometers) northwest of Oklahoma City, the report said.

The National Transportation Safety Board is investigating the cause of the crash....