On October 1, 2003, at 1803 eastern daylight time, a Walter A. Johnson homebuilt Hornet experimental airplane, N1928J, registered to and operated by the non-certificated pilot, collided with the ground following a loss of engine power in St. Mary’s, Georgia. The personal flight was operated under the provisions of Title 14 CFR Part 91, and visual flight rules. Visual meteorological conditions prevailed and no flight plan was filed. The non-certificated pilot sustained fatal injuries and the airplane was substantially damaged. The flight originated from a private grass strip in St. Mary’s, Georgia, at an undetermined time. According to witnesses in the area, the airplane had been circling when they heard the engine sputter. The airplane descended nose down behind a stand of trees and they heard a "boom". Several witnesses in the area telephoned the 911-operator and reported the accident. Examination of the wreckage on-scene found the airplane in a nose down attitude. Examination of the engine found one of the two sparkplugs out of its cylinder hanging by the sparkplug wire. During a telephone interview with the brother of the pilot he stated that about 15 to 20 hours prior to the accident they had done some maintenance on the engine including changing the spark plugs. He further stated that he believes that the spark plugs were not tightened adequately which allowed one to "blow out causing the loss of engine power". The Division of Forensic Sciences, Georgia Bureau of Investigation, State of Georgia conducted a postmortem examination of the pilot on October 2, 2003. The reported cause of death was "Blunt Force Injury, and the Manner of death was Accident". The Forensic Toxicology Research Section, Federal Aviation Administration, Oklahoma City, Oklahoma performed postmortem toxicology of specimens from the pilot. There was no Carbon Monoxide, no Cyanide or Ethanol detected in Blood, and no drugs detected in the Liver.