Investigators are still trying to determine what caused a private plane to crash in Kansas on Friday that took the lives of four people, including a Door County man. Twenty three year old Luke Sheets of Ephraim was piloting the twin engine cessna aircraft when it crashed in a field near Chanute, in southeastern Kansas. Authorities said Sheets had been in contact with air traffic controllers, but there was no distress call. The group, which left an airport near Tulsa, Oklahoma, were heading to a christian youth conference in Council Bluffs, Iowa at the time the plane went down. A twenty two year old passenger survived the crash with burns to more than a quarter of her body. Sheets was a recent graduate of Oral Roberts University in Tulsa, Oklahoma.