"Based on everything I’ve read about Fossett’s character and integrity, I simply can’t believe that he would fake his disappearance," Larson says. "I just think that it was a dumb accident." Numerous people claim to have spotted the blue-and-white Super Decathlon after Fossett took off around 9 a.m. on September 3, 2007, including a California highway patrolman, a ranger at Bodie State Park, and a man in Sodaville, Nevada, known as "Cathouse Tony." Larson, like most people familiar with the case, thinks that the key witness is Flying M ranch hand Rawley Bigsby, who made the last known sighting at around 11 a.m. and was familiar with the plane, since his boss at the ranch often flew it to check up on his workers.
Searchers have been aware of Bigsby’s account since the early days after the disappearance, but the import of crucial details—including the aircraft’s speed and altitude—has only recently been recognized. Larson argues that these facts provide powerful clues as to what might have happened next. Bigsby told investigators that the plane was flying very low, "60 to 80 feet off the deck," and at "low speed," as if "looking for a place to land." At the time, the Flying M employee was at his house, Nine Mile Ranch, which has its own landing strip. He said the plane was rocking slightly from side to side and the tail was pitching up and down. Fossett might have been struggling with a mechanical problem, which would explain why he may have been trying to put the plane down at Nine Mile instead of back at the Flying M.
Bigsby lost sight of the plane as it headed east over County Road O26 past Mud Springs Canyon. At that point, Larson says, Fossett was heading into a trap. Flying dangerously low, he was rushing toward terrain rising before him on three sides. Factoring in the altitude, air temperature, aircraft age, and engine performance, Larson has calculated that the Super Decathlon’s maximum rate of ascent would have been about 500 feet a minute (half the aircraft’s maximum climb rate of a thousand feet a minute)—not good enough to ascend above the mountains and avoid crashing.