In a rare departure from its normal practice, the National Transportation Safety Board (NTSB) reopened its investigation of an airplane crash to include critical evidence obtained by an outside party. The evidence, which directly led to a resolution of the crash and was incorporated in the NTSB’s final “Probable Cause” report, was obtained by investigators working with the law firm of Slack & Davis.
The crash took the life of Dr. Scott Hudelson, a dentist from Flower Mound, Texas, who for many years had served as the dental director at the Oklahoma School for the Deaf. Hudelson’s Cessna P210 crashed in central Kentucky while en route to a conference in Boston.
John Eakin, a Texas-based aviation safety analyst and editor of an online newsletter that examines airplane crashes for investigators, attorneys and other aviation safety professionals, characterized the NTSB’s inclusion of the evidence -- a leaking oil hose that led to engine failure – as highly unusual.
“A leaking oil hose was missed during the examination at the manufacturer's facility and not discovered until a subsequent teardown attended by all the litigants,” Eakin wrote in the March 8 edition of his newsletter, Airsafety.Com Information Report.
“That kind of thing happens. If these defects were obvious we wouldn't need professional investigators to find them,” Eakin added. “What makes this story different is that the NTSB investigator went the extra mile to reopen the investigation to include the newly discovered evidence.”
On November 12, 2004, the Cessna P210, N6539P Hudelson was flying was destroyed during a forced landing in Paint Lick, Kentucky. The single-engine airplane was in cruise flight at 19,000 feet when the pilot reported a loss of cabin pressurization, followed by a loss of engine oil pressure, and ultimately a total loss of engine power. With the assistance of air traffic control, Hudelson, a certificated commercial pilot, was able to maneuver the disabled airplane to a position near an airport, but was not able to successfully complete the emergency landing due to a low cloud ceiling in the area. The wreckage was mostly consumed in a post-crash fire.
After several months of investigation, the NTSB investigator, Paul Cox, was unable to determine the cause of the engine failure.
In May 2006, the NTSB released the engine and wreckage to parties in a lawsuit brought by the Hudelson family’s attorneys, Slack & Davis, who participated in an inspection of the evidence. Shortly after the engine components were unpacked and set out for examination, Slack & Davis investigative experts Lee Coffman and Bill Faircloth spotted a small hole in an oil line that provided oil to the turbocharger wastegate valve actuator. The suspect hose was made of synthetic rubber, reinforced by an outer layer of steel wire braid. In the course of their investigation, Coffman and Faircloth determined the braid exhibited signs of fraying and repetitive wear. They also noted the presence of black, oily deposits on the outside of the turbine housing adjacent to the breached oil hose.
All parties to the litigation were afforded an opportunity to observe and photograph the breached hose and related engine components. Subsequently, the parts were returned to the NTSB for examination, and the engine manufacturer filed an advisory with the NTSB reporting the findings of the litigant’s examination.
In September 2006, the litigants performed additional testing of the hose. This testing, initiated by Slack & Davis at their metallurgist's laboratory, led to the discovery of cast aluminum alloy deposits on the frayed surface of the hose; subsequent pressure testing of the hose indicated it had leaked. This testing established that the engine failure resulted from the breach of the oil hose, caused by improper mounting of the hose and inspection of the hose by maintenance personnel during prior service on the aircraft.
Upon learning this new information, the NTSB investigator incorporated the new information in his factual report. In February 2008, the NTSB issued its final “Probable Cause” report, concluding that the chafed oil line and its improper placement and alignment were responsible for the engine failure and crash that killed Dr. Hudelson.
“We need to commend Dr. Scott Hudelson, who showed amazing cool and airmanship in precisely narrating the unfolding events as the engine in his airplane failed and came apart,” said Slack & Davis attorney Michael Slack.
“We also should thank NTSB investigator Paul Cox, who was more interested in figuring out why the engine failed than in who figured it out first,” Slack noted. “Aviation safety would be better served if the NTSB were to adopt his approach and encourage its field investigators to consider the forensic work of litigants, which often produces a more complete and accurate picture than what can realistically be done during a governmental investigation.”
“Without the heroic efforts of the pilot, and the willingness of the NTSB investigator to consider outside input, this case may have gone down as another ‘engine failure unspecified’ in the NTSB database,” Slack said.
Relevant Links:
National Transportation Safety Board
http://www.ntsb.gov/
Air Data Research
http://www.airsafety.com/index.html
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