Thursday, July 09, 2009

Downdrafts cited by NTSB as probable cause of Steve Fossett's fatal crash

by B. N. Sullivan

Steve FossettThe U.S. National Transportation Safety Board (NTSB) has completed its investigation of the aircraft accident that claimed the life of legendary aviator Steve Fossett. The NTSB's final report on the accident cites as probable cause: The pilot's inadvertent encounter with downdrafts that exceeded the climb capability of the airplane. Contributing to the accident were the downdrafts, high density altitude, and mountainous terrain.

The NTSB found no evidence of engine malfunction or airframe failure that would have contributed to the accident.

Mr. Fossett, flying a borrowed Bellanca 8KCAB-180 Super Decathlon (registration N240R), disappeared on September 3, 2007. Early that morning, he took off from a private airstrip at the Flying M Ranch near Yerington, Nevada. He never returned.

An extensive and lengthy search for the aircraft and Mr. Fossett was unfruitful. According to the NTSB report, no emergency radio transmissions were received from the airplane, nor were any Emergency Locator Transmitter (ELT) transmissions received.

About a year later, on October 1, 2008, a hiker notified the Madera County Sheriff's Department (California) that he had found personal effects, including a pilot certificate and another identification card belonging to Mr. Fossett near Minaret Summit in the Sierra Nevada Mountains. This prompted a new search of that area.

The wreckage of the aircraft was found about a half mile from where the hiker came across some of Fossett's personal effects. The crash site was located in steep mountainous terrain at an elevation of approximately 10,000 feet. The severely fragmented wreckage had been burned by "a severe post crash fire."

The NTSB reports that after the wreckage was located, "a review of radar data from September 3, 2007, revealed a track that ended about 1 mile northwest of the accident site. This 20-minute track showed the airplane flying south along the crest of a mountain range with elevations greater than 13,000 feet."

Quoting from the synopsis of the NTSB accident report:
Examination of the accident site revealed that the airplane was on a northerly heading at impact, indicating that the pilot had executed a 180-degree turn after radar contact was lost.

Ground scars and distribution of the heavily fragmented wreckage indicated that the airplane was traveling at a high speed when it impacted in a right wing low, near level pitch attitude.

A postimpact fire consumed the fuselage, with the exception of its steel frame. The wings were fragmented into numerous pieces. The ELT was destroyed.

Damage signatures on the propeller blades and the engine crankshaft indicated that the engine was operating at impact. Examination of the airframe and engine revealed no evidence of any malfunctions or failures that would have prevented normal operation.

Visual meteorological conditions existed in the accident area at the time of the accident.

Mean winds at 10,000 feet were from 220 degrees at 15 to 20 knots; some gusts of 25 to 30 knots may have occurred. Moderate turbulence and downdrafts of at least 400 feet per minute probably occurred at the time and in the area of the accident. The magnitude of the downdrafts likely exceeded the climb capability of the airplane, which, at a density altitude of 13,000 feet, was about 300 feet per minute.
According to the Medical and Pathological Information section of the NTSB report, Steve Fossett is believed to have died as a result of "multiple traumatic injuries":
On October 29, 2008, law enforcement personnel returned to the area where the pilot's personal effects were found to search for human remains and evidence as to the identity of any remains. They found skeletal fragments, a pair of tennis shoes, clothing, credit cards and the pilot's driver's license.

DNA testing performed by a California Department of Justice laboratory on two of the recovered skeletal fragments determined that they were from the pilot.

A postmortem examination of the skeletal fragments was performed under the auspices of the Madera County Sheriff's Department. The cause of death was determined to be multiple traumatic injuries.
Here are the links to the NTSB synopsis and full narrative report on the investigation of this accident.

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