Those previous successes on risky missions were part of a pattern the NTSB identified as a partial cause of the deadly crash. The federal agency said the state should have put an end to such flights long before Nading died.
"As a result of inadequate, high-level management support, the Alaska Department of Public Safety lacked a safety program capable of highlighting the deficiencies uncovered in this accident, including training and risk management," the final NTSB report said.
When the state did act -- Nading was written up after several minor accidents -- it did so in the worst way, the report added.
"The Alaska Department of Public Safety had a punitive safety culture that impeded a free flow of safety related information and impaired the organization's ability to address underlying safety deficiencies relevant to this accident," the report said.
At the end of a four-hour hearing, the board ruled the direct cause of the accident "was the pilot's decision to continue flight under visual flight rules into deteriorating weather" but added that "also causal was the punitive culture and inadequate safety management" of public safety supervisors.
William Bramble, the NTSB's senior human performance investigator, said Nading was asked to complete a "high-risk mission" absent the sort of risk assessment procedures that "would have encouraged the pilot to decline the mission."
