On August 28, 2001, at 1645 central daylight time, a Grumman G164B agricultural airplane, N2LU, was substantially damaged during a forced landing following a loss of engine power near Rayville, Louisiana. The airplane was registered to and operated by Barham Bros Inc., of Oakridge, Louisiana. The commercial pilot, sole occupant of the airplane, was not injured. Visual meteorological conditions prevailed and no flight plan was filed for the 14 Code of Federal Regulations Part 137 aerial application flight. The local flight originated from the Hooks Memorial Airport, Rayville, Louisiana, at 1530. According to the pilot, he had been applying malathion to a field for approximately 1 hour and 15 minutes when the engine began "backfiring and running rough." A loss of engine power ensued and the pilot executed a forced landing to a field. The airplane touched down and rolled approximately 200 feet before the "left main gear hit [a] small mound of grass and dirt." Subsequently, "the aircraft nosed over very gently onto its back," and came to rest inverted. Post accident examination of the airplane, by an FAA inspector and the operator, revealed that the drive coupling on one of the magneto's was "sheared but not completely." According to the operator the magneto had accumulated a total of 807.0 hours. They reported that the airplane's tail section sustained structural damage.