On September 5, 2000, about 1214 hours Pacific daylight time, a Williams Mite M18L, N60BW, owned and operated by the pilot, experienced the in-flight separation of its vertical stabilizer and rudder assemblies approaching the Gillespie Field, San Diego, California. Visual meteorological conditions prevailed at the time, and no flight plan was filed. The experimental airplane was substantially damaged, and the private pilot was not injured. The personal flight was performed under 14 CFR Part 91, and originated from Oceanside, California, at an unreported time. The pilot indicated that on final approach about 50 feet above ground level, the airplane's entire stabilizer and rudder assemblies separated from the airplane, as a single unit. Thereafter, the airplane veered sharply to the right, and there was a strong tendency to roll inverted. The pilot regained control of the airplane, extended the landing gear, and landed on runway 17 without further mishap. The separated components were subsequently located on airport property. The Federal Aviation Administration examined the components and reported observing evidence of dry rot on the fracture surfaces.