Contact with the plane was lost shortly after air traffic control authorized a descent to a lower altitude, Knudson said.
The transportation safety board is investigating the accident, and a preliminary report will be issued within 10 business days.
The five people on the plane were headed to a Christian youth conference in Iowa, according to a statement issued Saturday by Texas-
Luce is daughter of Teen Mania founder, Ron Luce, a member of the Oral Roberts Board of Trustees.
Anderson and Luth recently were hired for the organization's marketing staff. Coble had been on 15 previous mission trips for the organization. Anderson was also a staff sergeant in the U.S. Marine Corps who served two tours in Iraq, according to a statement.
Contributing: The Tulsa World.