Acceptable Risk

Do you know your acceptable risk level?

At about 8:25 A.M. on Sept. 3, 2007, Steve Fossett took off from a friend's ranch, about 60 miles southeast of Reno, Nevada, in a borrowed 1980 Bellanca Super Decathlon. A few minutes later, about nine miles south of the airstrip, an employee of the ranch who knew the airplane well saw the Decathlon fly past 150 or 200 feet above the ground.

Fossett did not come back. The search for him, unusually intense because of Fossett's prominence, wealth and wide connections in aeronautical circles, turned up nothing, and in due course it was suspended. Although his buddy Richard Branson predicted that he might, Fossett did not hike out of the wilderness unharmed. He was legally declared dead after five months, and fanciful theories that he had faked his death in order to escape money troubles or to settle in the South Seas with a beautiful mistress began to sprout.

Thirteen months after Fossett's disappearance, a Sierra hiker chanced upon some papers that were his. Searchers returned to the area, and two days later the severely fragmented wreckage of the Decathlon was located about half a mile from the first find. Fire had consumed most of what might have been visible to aerial searchers, who had flown over the debris without noticing it.

There was nothing in the wreckage to suggest a mechanical problem. Both propeller blades, which had broken out of the hub, showed the type of bending and scoring that indicates that the engine was developing power on impact. The aluminum wing structure ­- the airplane, originally equipped with a fabric-covered wood wing, had been rewinged in 1996 -- was severely twisted and mangled, but the strut attachments were secure. The engine, found 100 feet uphill from the main wreckage, was heavily damaged. Investigators concluded that the airplane had been in level flight and a right bank, moving at a relatively high speed, when it struck the southern flank of a northwest-southeast-oriented ridge at about the 10,000-foot level.

A 20-minute radar track that began at 9:07 a.m. and led almost directly to the accident site had been ignored by accident investigators because the ranch employee who had seen Fossett fly past had put the sighting at around 9:30, based on a cell phone call he had at the time. A belated check of telephone company records revealed the call had actually taken place at 8:30. The seemingly inconsistent radar track then seemed likely to be the Decathlon's. It began about 35 miles south-southwest of the ranch with several minutes of beacon returns squawking 1200 and reporting Mode C altitudes of 14,500 to 14,900 feet. The transponder returns then ceased, and the remainder of the track consisted of primary echoes ending about a mile northwest of the site.

Arguing for the identification of the radar track as Fossett's was not only its termination close to the accident site, but the fact that its starting point, at 14,500 feet -- 1,500 feet above the mountaintops -- was consistent with the witness sighting half an hour earlier. The Decathlon, climbing on the lee side of the mountains -- the wind was out of the south-southwest at an estimated 18 knots, gusting to 34 -- would have required less than half an hour for the 9,000-foot altitude gain, and it was likely it might have traveled 26 nautical miles while climbing against the wind. In level flight and descending, during the 20-minute radar track, it averaged only 90 knots. The NTSB didn't comment on the sudden appearance of the track -- which may have been due to incomplete radar coverage -- or on the termination, after several minutes, of the transponder returns.

A camper reported having seen what he thought was Fossett's airplane flying southward. He said it "looked like it was standing still due to the wind." The camper's sighting, at "a little before 1000" and 30 miles from the accident site, did not mesh well with the NTSB's timeline, but the observation was one of several that the NTSB included to bolster its finding that the probable cause of the crash was "downdrafts that exceeded the climb capability of the airplane." Other pilots who had flown in the area that day gave mixed reports. One said it was "a wonderful day to go flying," with 10-knot winds aloft and no "big turbulence." Another characterized the day as "weird, … unusually smooth [with] random rough chop."

Based on the forecast winds aloft, the NTSB decided that "moderate turbulence … probably occurred." A computer simulation predicted downdrafts of as much as 400 feet per minute -- that is, about four knots. The airplane's manual claimed a climb rate of 300 fpm at the prevailing density altitude of 13,000 feet.

Returning to comb the area nearly a month after the discovery of the wreckage, sheriff's personnel found clothing, credit cards, Fossett's driver's license and a few bones that were subsequently determined by DNA testing to be his. The cause of death, based on these "skeletal fragments," was determined, in a bold forensic leap, to be "multiple traumatic injuries." Nevertheless, the distance between the wreckage and the remains, and the fact that both front-seat belt buckles (the airplane had both five-point acrobatic and standard seat belts for both seats) were found unlatched, suggested to some that Fossett might have survived the crash and moved several hundred yards before succumbing to his injuries.

The fanciful speculation that Fossett had faked his own death dwindled once the airplane, the personal effects and the bones had been found. The real mystery was a less titillating one: How, or why, did a 6,000-hour ATP fly into a mountain in broad daylight?

Unfortunately, the only evidence of anything resembling pilot intention is the disappearance of the transponder signal, at an altitude of 14,900 feet. Three interpretations are possible: The transponder could have failed spontaneously; the receiving station could have failed for some reason to pick up its returns; or Fossett himself could have turned it off. Since the area is very close to Yosemite National Park, and low flight within national parks is frowned upon, it is conceivable that Fossett decided to get down closer to the terrain and, being uncertain of his exact position in relation to the park, turned off the transponder in an exercise, so to speak, of his Fifth Amendment rights.

Clearly, Fossett must have been flying low in order to hit the mountain; a 400-fpm downdraft could not possibly produce a loss of thousands of feet of altitude followed by an uncontrolled collision with a ridge. There were too many escape routes. But the downdraft theory may appear inconsistent with a high-speed impact. A Decathlon caught in a downdraft and struggling to avoid terrain would most likely be flying slowly, not fast.

But slow is relative. Fossett, who owned and flew a Citation X, may have been reluctant to get the Decathlon as slow as it could really go, especially while turning hard in turbulence. At that density altitude, 70 kias is 85 ktas, and if he had a 20-knot wind behind him he could actually have been moving at 105 knots -- perhaps fast enough to account for the condition of the wreckage. A problem with the downdraft-plus-wind scenario, however, is that Fossett crashed into a windward slope; there should have been an updraft, not a downdraft.

Another possibility, which the NTSB doesn't mention, is what might be called the Cory Lidle scenario. Lidle was the Yankees pitcher who crashed his plane into a Manhattan apartment building in 2006 while trying to reverse course within the confines of the East River. A strong east wind was blowing. If Lidle and his instructor had been flying along the downwind edge of the river and turned into the wind, they would have completed the turn safely; but they were flying along the upwind edge, and the wind carried them over into Manhattan.

Fossett crashed on the northeastern slope of a valley that ascended toward the northwest. It is possible that, flying generally northwestward, he had descended deeper into the valley than he intended -- perhaps because of a downdraft from the southwestern slope -- and then tried to escape by making a right turn. The wind, blowing from the southwest, possibly gusty, and gaining speed near the ridge, could have carried him wide, into the mountain.

It has been seen as ironic that Fossett, who had made so many remarkable flights, including three solo nonstop trips around the world in the GlobalFlyer and the first solo balloon circumnavigation of the globe, and had collected so many world records, should end his life on a mere Sunday drive. It was as if a soldier, after surviving many battles, should succumb to an infected bug bite. But Fossett did not accomplish his feats by being overly fussy about danger or averse to thrills. The risk in swooping down for a closer look at the Sierra landscape may have seemed acceptable, even beneath his notice. In aviation, there is no paradox in being cut down by a small danger after having eluded big ones; the one that gets you is big enough.

This article is based on the NTSB's report of the accident and is intended to bring the issues raised to our readers' attention. It is not intended to judge or to reach any definitive conclusions about the ability or capacity of any person, living or dead, or any aircraft or accessory.