The other pilots reported Hemman missing.
Investigators determined that Hemman crashed at about 10:40 a.m. 15 miles southwest of Cantwell. A community fire crew spotted fire from the crash at around noon.
Wreckage of the aircraft, equipped with two 300-horsepower engines, was spread over 726 feet of brush and tundra, indicating a high-speed crash.
Five video cameras mounted on the airplane's exterior were recovered and sent to the NTSB vehicle recorder laboratory in Washington, DC, for review. A final crash investigation report could take nine months or longer.