Meanwhile, in a separate press release, an attorney for Quinn and his mother blamed ERA for failing to install a $30 guard for the fuel controls.
The senior Ellington says changes need to be made to the helicopter's design, something the NTSB is looking into.
The Eurocopter AS-350-B2 is the only helicopter operating in the U.S. with floor-mounted fuel control levers, Jim La Belle, chief of the NTSB's Alaska region office, said.
"The rest of them are all overhead or on the collective, which is a hand control that the pilot has," La Belle said Wedneday. "So this is unique, this is a unique helicopter, a unique environment, and that control, that fuel control lever, is very vulnerable."
And if Ellington's backpack is to blame, the pilot failed to take measures to secure it, the NTSB report says.
The board's determination goes on to say that ERA also failed to properly track the helicopter or report it overdue, which would have prompted a quicker search and rescue operation.
It's typical that multiple factors contribute to aircraft accidents, La Belle said.
"This involved the trilogy we see all the time in accidents -- the man, and the machine and the environment interface," he said. "It was obviously, like I say, a catastrophic accident with some tragedy, some real human tragedy here."
The NTSB is now working with the Federal Aviation Administration to address the helicopter's design issues, La Belle said. The result could be a recommendation that the design be changed or that a guard be required for the floor-mounted fuel levers, he said.
"ERA knew that well prior to this 2008 crash there were instances where passengers were known to have unintentionally or inadvertently interfered with these controls, again, located between the two seats. So the question is what did Era do about it and the answer is they did nothing about it," said Joe Stacey, an attorney for Ellington and his mother, Teri Seward.
Ellington's family says they may fight back with a lawsuit against Era.
The April 15, 2008 crash killed Ellington's stepfather, 37-year-old Palmer resident Michael Seward, 46-year-old Anchorage resident Thomas Middleton, 48-year-old Girdwood resident Joseph O'Donnell, and 39-year-old Anchorage resident Benoit Pin, the ERA pilot.
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