On August 22, 2015, at 1655 Atlantic standard time, a Cessna 150M, N4057V, was substantially damaged during a forced landing in Dorado, Puerto Rico. The private pilot was seriously injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the flight from Fernando Luis Ribas Dominicci Airport (TJIG), San Juan, Puerto Rico, to Rafael Hernandez Airport (TJBQ), Aguadilla, Puerto Rico. The personal flight was operating under the provisions of 14 Code of Federal Regulations Part 91.According to the pilot, he had flown the airplane that morning to the island of Culebra, returning before noon with no anomalies noted, either during that flight, or during the accident flight's preflight inspection or engine run up. The airplane subsequently departed TJIG runway 27, heading west toward TJBQ, about 1640. About 15 minutes later, at an altitude of 1,000 feet, the pilot smelled smoke. He notified the TJIG air traffic control tower and advised that he was turning around. The pilot "cautiously" reversed course, and a few minutes later, a "lot of smoke started to invade the cabin." The pilot turned the master switch off and looked for what was causing the smoke and any sign of a fire. The smoke did not stop so the pilot had to decide whether to continue to the airport or find a safe place to land. At that moment, the airplane was over an open, unpopulated field that the pilot had flown over many times before, which looked flat and "clean enough" for a safe landing. Beyond the field was "Metro San Juan," and the pilot would have had to fly over San Juan Bay before reaching TJIG. Since the smoke continued, the pilot decided to land the airplane in the field and not risk continued flight. The pilot identified a landing spot in the field, and followed emergency procedures "from right to left, cut the gas and the engine stopped." The pilot descended the airplane "aggressively to increase airspeed, following the in-flight fire procedures." About 300 feet, the pilot leveled the airplane and set up the approach for landing. The airplane touched down with both main landing gear "as gently as possible" since the grass was high, and during rollout, the pilot noticed high bushes in front of him. The pilot used the momentum of the airplane to "elevate" it over the bushes by pulling back on the yoke forcefully. The pilot then felt the airplane, "hit something and everything started to move violently." The pilot initially lost consciousness, but later regained it and pulled himself out of the airplane. He was subsequently taken to the hospital, where he learned that the airplane had hit a "water contingency dirt wall" hidden by the bushes, and that the entire front of the airplane was severely damaged and displaced into the cabin. According to the responding Federal Aviation Administration inspector, the airplane landed in a park about 6 miles west of TJIG. Examination of the airplane revealed engine compartment electrical arcing, and melting of the plastic covering the battery grounding wire. The source of the arcing could not be determined. The pilot reported that the airplane had been operated about 40 hours since its most recent annual inspection, which was performed about 4 months prior to the accident.