The NTSB on Thursday released its final report on the Sept. 3, 2007 airplane crash that claimed the life of adventurer Steve Fossett, saying that his aircraft, a borrowed American Champion Super Decathlon (N240R), hit the side of a mountain near Mammoth Lakes, Calif., after “an inadvertent encounter with downdrafts that exceeded the climb capability of the airplane.” According to the NTSB, also contributing to the accident were the high-density altitude and mountainous terrain. Sole-occupant Fossett departed Flying M Ranch, a private airport near Yerington, Nev., on a local flight and failed to return. A month-long search by the Civil Air Patrol, state and county authorities and Fossett’s friends failed to locate the aircraft. Last October 7, a man hiking near Mammoth Lakes discovered a pilot certificate and other items that belonged to Fossett. A subsequent aerial search located the airplane wreckage about a half-mile from the pilot’s personal effects, at an elevation of about 10,000 feet, the Board said. After the wreckage was discovered, a review of radar data from the day of the crash revealed a track that ended about one mile northwest of the accident site.