On April 30, 1997, at 1620 hours Pacific daylight time, a Cessna 140, N2031N, owned and operated by the pilot, crashed during an attempted takeoff from runway 30 at the Palo Alto Airport of Santa Clara County, Palo Alto, California. The airplane was destroyed, and the commercial pilot received minor injuries. Visual meteorological conditions prevailed during the personal flight, and no flight plan was filed. The flight was originating at the time of the accident. According to the pilot, he applied engine power and the airplane accelerated normally. Upon reaching an altitude approximately 50 feet above the runway, the airplane suddenly banked right. The pilot attempted to lower the left wing by applying opposite aileron. He stated that his efforts were not adequate, and he lost control of the airplane as the nose pitched down. The airplane's right wing and engine then contacted the ground. The engine separated from the airframe, and the propeller separated from the engine. The airplane came to rest in an upright attitude in an open dirt field about 150 feet from the runway's edge. The pilot reported that no mechanical malfunction or failures were experienced during the flight. The Federal Aviation Administration coordinator (FAA) examined the airplane wreckage. According to the FAA, the airplane's fuel system had been modified by the addition of outboard wing fuel tanks. The airplane's total fuel tank capacity had been increased from the standard 25 gallons to about 60 gallons. The pilot reported having about 55 gallons of fuel onboard during the attempted takeoff. This added capacity raised the airplane's gross weight, and the stall speed increased by 6 miles per hour. The pilot additionally reported to the FAA that the airframe modification had been performed under his direction. No logbook maintenance entries were found relating to the work. The FAA reported that it had not approved the modification.