On May 1, 2005, about 1241 Pacific daylight time, a Pitts S-2A, N5300V, ground looped during landing at Tracy, California. The owner was operating the airplane under the provisions of 14 CFR Part 91. The certified flight instructor (CFI) was not injured, and one passenger sustained minor injuries. The airplane sustained substantial damage. The local personal flight departed Tracy about 1150. Visual instrument meteorological conditions prevailed, and no flight plan had been filed. The pilot submitted a Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2). He stated that he departed the airport to go to the practice area. Upon returning to the airport, he used a slipping final for visibility, and to correct for a crosswind. When the wheels touched down, the airplane began to deviate left of center. The pilot corrected to the right, the left wing contacted the ground, and the airplane crossed to the right side of runway. The prop struck the runway and the airplane slowly nosed over. The pilot then turned off the fuel, master switch, and grounded the magnetos. Both occupants exited from the inverted airplane by sliding the canopy open. The closest official weather observation station was Stockton Metro (SCK), which is located 15 nautical miles (nm) northeast of the accident site. An aviation routine weather report (METAR) for Stockton was issued at 1255. It stated: winds variable at 06 knots; visibility 10 miles; skies clear; temperature 23 degrees Celsius; dew point 08 degrees Celsius; altimeter 30.05 inHg. The pilot reported that the weather at Tracy was: winds from 280 degrees at 12 knots; visibility 20 miles; skies 8,000 feet scattered; temperature 63 degrees Fahrenheit. The pilot stated that the airplane and engine had no mechanical failures or malfunctions during the flight.