On September 19, 2011, about 0850 Pacific daylight time (PDT), a Pitts S-2B airplane, N46BT, collided with the ground near Redlands, California. The private pilot, the sole occupant, sustained serious injuries. The airplane was consumed by fire and sustained substantial damage. The airplane was registered to the pilot, and operated under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91 as a personal flight. Visual meteorological conditions prevailed and no flight plan had been filed. The flight originated from the Redlands Municipal Airport, Redlands, California, about 0830. Witnesses reported that the pilot was conducting aerobatic maneuvers over the airport when the airplane impacted terrain adjacent to an airport perimeter fence. After impact, the airplane slid into an unoccupied vehicle that was parked on the shoulder of a city roadway. A post crash fire ensued. The pilot reported that he was maneuvering in the local area shortly after takeoff and that during a turn, the airplane stalled approximately 350 feet above the ground. He reported that the airspeed in the turn was slow, between 70-80 knots. The pilot attempted to recover from the stall; however, the airplane continued to descend and subsequently collided with terrain. First responders to the accident site reported that they noted an odor of alcoholic beverage when they made contact with the pilot at the accident site. About one hour after the accident a blood sample from the pilot was secured, and later tested for alcohol intoxicants. The test results showed that the pilot’s blood alcohol content (BAC)was .04 percent. During a telephone conversation after the accident with the NTSB investigator-in-charge, the pilot stated that he had consumed alcohol prior to the accident flight. The pilot reported no preimpact mechanical malfunctions or failures with the airplane that would have precluded normal operations. According to the Federal Aviation Administration, effects of a BAC of .04% can include decreased attention, impaired judgment, and increased reaction time. It advises that "The number of serious errors committed by pilots dramatically increases at or above concentrations of 0.04% blood alcohol. This is not to say that problems don’t occur below this value. Some studies have shown decrements in pilot performance with blood alcohol concentrations as low as 0.025%." Title 14 CFR Part 91.17, Alcohol or Drugs, states, "(a) No person may act as a crewmember of a civil aircraft (1) Within 8 hours after the consumption of any alcoholic beverage; (2) While under the influence of alcohol…(4) While having an alcohol concentration of 0.04 or greater in a blood…"