On July 5, 2005, at 1845 central daylight time, a single-engine Grumman AA-1B airplane, N1466R, was substantially damaged during an overrun when it impacted terrain following a reported loss of engine power during takeoff near Llano, Texas. The airplane was owned and operated by a private individual. The private pilot received serious injuries and his passenger received minor injuries. Visual meteorological conditions prevailed and a flight plan was not filed for the 14 Code of Federal Regulations Part 91 flight. The local flight was departing from the Llano Municipal Airport (AQO), near Llano, Texas, at the time of the accident, and was destined for the Eldorado Airport (27R). The 204-hour private pilot reported in the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2) that he picked up a passenger at AQO, and prior to departure he filled the left tank with fuel. He also stated that the right tank contained approximately 7 gallons of fuel. The pilot added that it was a "hot and muggy" afternoon. The pilot departed runway 17 (4,202 foot by 75-foot asphalt), and after reaching 50-75 feet above the ground, he reported that the engine "started to lose power and settled back to the ground". At that point, the pilot elected to abort the take-off. The airplane overran the departure end of the runway, coming to rest in the inverted position in a wooded area, off the departure end of the runway. An FAA inspector examined the airplane at the accident site and reported the right wing and nose gear had been sheared-off. Additionally, the airplane had extensive damage to the canopy, fuselage, and empennage. The density altitude was calculated by the NTSB investigator-in-charge to be 3,967 feet. A review of the weight and balance calculations revealed the aircraft was within a few pounds (+/-) of it's maximum take-off weight of 1,560 pounds. Examination of the airplane was conducted on July 13, 2005, at the facilities of Air Salvage of Dallas, near Lancaster, Texas, by a representative from Lycoming, under the supervision of the NTSB investigator-in-charge. The Lycoming engine was successfully run for approximately 5 minutes at various power settings. The engine was run to full throttle, which resulted in an rpm reading of approximately 2,200. An additional 150 rpm was gained by leaning the engine. Per the Type Certificate Data Sheet the minimum static rpm should be 2150 rpm at the maximum throttle setting (McCauley 1A105/SCM-7157 propeller). At 1905, the automated weather observing system at AQO, reported calm wind, 5 miles visibility in haze, sky clear, temperature 97 degrees Fahrenheit, dew point 64 degrees Fahrenheit, and an altimeter setting of 29.95 inches of Mercury.