Investigators found no fuel in the small plane that crashed in Nowata County last weekend.
The three Alabama men on board the single-engine Beechcraft BE-36 survived the crash. The Oklahoma Highway Patrol identified them as Paul Woolard, 50; Randy Watson, 54; and Ryan Bozeman, 25.
The OHP said Woolard was the pilot.
The airplane had taken off from Washington County Memorial Airport in Washington, Kansas on the afternoon of April 27, 2014.
According to the Preliminary Report from the National Transportation Safety Board, one of the passengers told investigators the plane was headed to Shawnee but the pilot diverted to Claremore because of strong head winds. The plane crashed in a field near the town of Wann at 1:38 p.m.
The NTSB says air traffic control noticed the plane was descending on radar without a clearance. When contacted by radio, the pilot told them he was having engine problems.
According to the NTSB, an FAA inspector examined the airplane and found no fuel in the fuel tanks, "no evidence of fuel stains on the airplane or ground, and no odor of fuel. An examination of the engine revealed no anomalies."
The next report on the crash will be the Factual Report, which usually takes the NTSB several months to complete. It will be followed by the Probable Cause Report.