A close look at documents from the U.S. National Transportation Board (NTSB) and a company it’s placing much of the blame on for a 2008 helicopter crash reveals a sharp contrast in viewpoints from the government investigators and the operator—Perkasie, Pa.-based Carson Helicopters—as to what led the Sikorsky S-61 to fall from the sky. With all the “he said, she said” allegations flying from NTSB investigators, Carson and the co-pilot who survived the crash, it’s hard to pinpoint exactly the real cause—it depends on who you talk to. Throw in claims of evidence tampering and the picture just gets cloudier.
Franklin Carson, president of Carson Helicopters, issued a scathing open letter [PDF] last week to dispute the findings of NTSB’s two-year probe into the crash. The helicopter, which was under contract with the U.S. Forest Service, went down on Aug. 5, 2008 in the mountains near Weaverville, Calif. Nine people were killed, including seven firefighters and the pilot, while four others were injured, including co-pilot William Coultas, who disputed NTSB’s findings following a Dec. 7 public meeting where board members revealed the accident’s probable cause.
NTSB pinned much of the blame on Carson Helicopters, while acknowledging the role of improper oversight by FAA and the Forest Service. Among the reasons cited were Carson’s “intentional” understatement of the helicopter’s empty weight, altering of the power available chart and practice of using above minimum specification torque figures in performance calculations, which resulted in the pilots overestimating the load capability of the S-61. But Franklin Carson disagrees.
The company “strongly believes that the accident was caused by the loss of power to the #2 engine due to contamination in the fuel control, which the NTSB chose to ignore even after reviewing indisputable evidence brought to its attention,” he wrote.
Carson also asserted that NTSB disregarded the copilot’s “direct testimony that he saw signs of power loss in the #2 engine immediately prior to the crash,” adding that investigators “ignored his direct reading of the actual air temperature at the scene in favor of manufactured data that fit their preconceived narrative.”
The company president also claims that NTSB mishandled important evidence related to the probe, including parts from the fuel control unit (FCU). After losing the parts during the early part of the probe, investigators “from that point forward did not pursue evidence chains leading to the fuel control units,” he wrote.
There was also an issue with “significant contaminants” up to 28 microns found inside the #2 FCU. “There is a history of power loss problems due to contaminants in the FCU because of inadequate fuel filtering that was known by the manufacturer and not properly explored by NTSB,” Carson wrote. He added that the company notified Sikorsky and engine maker GE about the safety concern six years ago, with GE recommending that Sikorsky change the requirements for the filter from 40 to 10 microns two years before the accident, in 2006.
“The day after the accident, GE e-mailed Sikorsky asking what was being done about changing the airframe fuel filter. It wasn’t until almost two years after the accident that Sikorsky issued a service bulletin changing the approved filter from 40 microns to 10 microns,” he wrote.
Carson also challenged the assumption that the error on the weight chart was intentional. The company “is not disputing that a Carson employee submitted incorrect information on the empty weight of the aircraft and the performance chart, but NTSB’s suggestion that it was condoned by the company is totally false and misleading.”
He notes that Carson Helicopters has been bound by limitations of being part of the investigation team, but “in light of NTSB’s arbitrary and one-sided hearing” on Dec. 7, the company could not “stand silently by while NTSB ignores an ongoing safety of flight issue by trying to make Carson a scapegoat.”
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