ANCHORAGE, Alaska (AP) — National Park Service officials say a 62-year-old man died after being struck by the rotating propeller of his own plane at Alaska’s Wrangell-St. Elias National Park and Preserve.

Park officials say Clark J. Baldwin of Wasilla was killed in the incident late Thursday morning at a park airstrip.

Clint Johnson, head of the National Transportation Safety Board’s Alaska office, says it’s his understanding that Baldwin’s Piper PA-18 Super Cub was idling and for an unknown reason he walked into the propeller.

Baldwin died at the scene.

Chief Park Ranger Peter Christian says Baldwin was a retired Air Force lieutenant colonel who owned and operated a Super Cub training business called Alaska Cub Training Specialists. Christian says three other Super Cubs were at the airstrip, and six people witnessed the accident.