On March 30, 2002, at 1537 Pacific standard time, a Piper PA-22-160, N8158D, nosed over after veering off the runway during landing at the Vacaville, California, airport. The airplane was owned and operated by the pilot under the provisions of 14 CFR Part 91, and sustained substantial damage. The private pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed for the cross-country personal flight that originated at the Beagle Sky Ranch Airport in Medford, Oregon, with a destination of Vacaville. In a telephone interview, the pilot said the airplane is a conversion to the PA-22/20 conventional landing gear arrangement. He had just picked up the airplane after having it in the shop for the last couple of months for repair. He was landing on runway 20 with winds he described as from 100 degrees at 6 knots. After touchdown, he experienced directional control problems with the airplane first veering left and then right, and finally departing off the right side of the runway. The airplane was traveling at a slow speed and he applied both brakes to stop. The airplane then nosed over very slowly, damaging the vertical stabilizer. He stated there were no mechanical malfunctions or failures with the airplane. The pilot reported that his total time was 140 hours, with about 60 in the accident aircraft. Prior to departing from Medford, he obtained some dual instruction to review landing techniques in conventional gear airplanes. The official Vacaville aviation METAR at both 1453 and 1553 was reporting variable wind conditions at 3 to 4 knots.