On July 14, 2018, about 1740 Atlantic standard time, an experimental light sport Quicksilver MXL II, N594TC, was substantially damaged when it impacted terrain during a forced landing at Antonio (Nery) Juarbe Pol Airport (ABO), Arecibo, Puerto Rico. The non-certificated pilot sustained serious injuries. The airplane was operated by the pilot as a personal flight conducted under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and no flight plan was filed for the local flight, which departed at 1630.According to a Federal Aviation Administration (FAA) inspector, the pilot reported that he was returning to ABO after about a one-hour local flight and approached runway 8. During the approach, he performed a go-around and subsequently encountered strong wind, and decided to turn 180° to land on runway 26. While turning, about 1/2 mile from runway 26, the engine experienced a total loss of engine power. The pilot landed straight ahead into marshy terrain in a nose low attitude. The pilot reported that he took off with 5 gallons of fuel on board. According to a FAA inspector who examined the airplane at the accident site, the airplane sustained substantial damage to the empennage and fuselage. Flight control continuity was confirmed from the flight control surfaces to the cockpit. Engine cylinder compression and powertrain continuity were established by rotating the propeller by hand. The fuel selector was found in the off position. The fuel tank was found empty, the fuel cap remained secured, and there was no sign of fuel leakage. The fuel filter container was about 1/2 full of fuel. The ABO airport's daily aircraft activity logbook showed that the accident airplane departed at 1630 local, which resulted in a total flight time of 1 hour and 10 minutes. According to FAA airman records, the pilot was issued a third class medical and student pilot certificate in December 2011, which expired in December 2013. There was no record found that the pilot held an airman certificate. According to Title 14 Code of Federal Regulations Part 61, the pilot was required to hold at least a student pilot certificate, with appropriate solo endorsements, to operate the airplane. According to FAA airworthiness records, the two-seat, single-engine, high-wing airplane was manufactured in 1995. It was equipped with a Rotax 503 DI/SC engine. The airplane had a total fuel capacity of 6-gallons. The Rotax 503 engine data sheet stated that the fuel consumption was about 5.3 to 6 gallons per hour. The weather conditions reported at 1750 at Rafael Hernandez Airport (BQN), Aguadilla, Puerto Rico, 27 miles from the accident site, included wind from 090° at 16 knots, gusting to 23 knots, visibility 10 statute miles, broken clouds at 1,800 ft, temperature 28°C, and dew point 23°C.