On March 29, 2007, at 1550 eastern daylight time, a Beech BE-58, N1MQ, registered to Airway Partners LLC, operating as a 14 Code of Federal Regulations Part 91 personal flight, experienced a right wing in-flight fire while on approach to the Spalding County Airport (6A2), Griffin, Georgia. Visual meteorological conditions prevailed , and no flight plan was filed. The airplane received substantial damage. The commercial pilot and two passengers reported no injuries. The flight departed Cobb County McCollum Airport (RYY), Marietta at 1530. According to the pilot, while in cruise flight at 2,500 feet, he felt a "thump" and observed that the right wing had structural damage. He slowed the airplane to 120 knots to verify that he still had positive control of the ailerons. At that point he observed black smoke or soot on the outer third of the aileron, and believed that the wing was on fire at that time. He moved the right engine throttle to idle, feathered the propeller, and pulled the mixture to cut-off. He made an emergency descent to a landing at a private airport in Woolsey, Georgia. After landing, he and his passengers egressed the airplane and extinguish the fire on the right wing. Examination of the right wing found extensive fire damage concentrated in the center of the wing, with ballooning of the wing skin, and soot trailing over the right aileron. Removal of the wing skin found heavy sooting within the wing cavity and molten aluminum. Also, observed were several pieces of fuel vent line, which had heat fractured into 3 to 4 inch pieces. No liquid fuel was observed and the fuel tank was not damaged. The source of fuel/fuel vapor, or the ignition source that started the fire could not be identified due to the extent of the fire damage.