At 06:20 eastern time, a Cessna 206H suffered an in-flight fire and crashed in a field in Mayville. The pilot was seriously injured. The pilot reported he was in cruise flight when an explosion occurred in the engine compartment. Flames immediately emanated from both sides of the engine, and smoke filled the cockpit. The pilot maneuvered the airplane toward some open fields, but had difficulty breathing and seeing outside the cockpit. He attempted to land in a clear area but clipped trees during the approach. The airplane was manufactured in May 1999 and had flown about 350 hours.