ANCHORAGE -

A National Transportation Safety Board investigation of a deadly Alaska State Troopers helicopter crash near Talkeetna has unearthed revelations about aircraft operations at the state Department of Public Safety.

More than 2,200 pages of documents on the March 30 crash of Helo-1, which killed pilot Mel Nading, Trooper Tage Toll and snowmachiner Carl Ober, were released Monday. In addition to an extensive examination of Nading's record contained in a personnel analysis, the investigation also raises questions about whether senior DPS officials adhered to stated policy regarding authority over pilots and repairs.

NTSB spokesperson Clint Johnson says the Helo-1 crash is being investigated as a major accident, with a "go team" sent from Washington, D.C. to individually examine various elements of the incident. He says the last Alaska crash to receive such scrutiny was the August 2010 crash of a De Havilland DHC-3 Otter near Dillingham, which killed former Sen. Ted Stevens and three other people.

According to Johnson, the focus in the NTSB documents on Nading's history is a common element in major accidents, with investigators routinely assigned to closely examine the accident pilot's background.

"That is very standard, providing for any type of human performance investigator, and that's where that information is coming from," Johnson said. "It's coming from the human performance (group) and that's what they do. That's their specialty -- looking into training, looking into past history."

Johnson says the investigation of the Helo-1 crash is roughly 75 percent complete, with NTSB chair Deborah Hersman opening the case's files to the public at 51 percent completion.

Within DPS, aircraft operations are handled by the Division of Alaska Wildlife Troopers. The NTSB says a chain of command was in place for troopers' handling of DPS aircraft, including both AWT's director and deputy director, below who were a captain, the lieutenant commanding the aircraft section and a supervisor of the section.

NTSB investigators spoke with Tory Oleck, the lieutenant commanding the aircraft section, who said that then-AWT Director Col. Gary Folger had created Oleck's position in August 2011 to lighten workloads he had personally taken on.

"(Oleck) said that the captain and major were not pilots and that the colonel was a pilot; 'generally he was able to go directly' to the colonel, who made 'a lot of the ultimate decisions,'" NTSB officials wrote. "Before (Oleck) came, the supervisor had been asking the colonel for guidance, and after he came, 'when troopers in the field had questions about needing maintenance or an airplane or something,' instead of the supervisor asking the colonel, he responded to their questions."

Sherry Hassell, a former aircraft section supervisor at AWT, told the board that she saw similar deviations in the chain of command.

"(Hassell) explained that she was listed as (Nading's) supervisor, but 'in reality' he was supervised by the AST SAR coordinator, and she 'wasn't even involved in any of his flights,'" NTSB officials wrote. "The SAR coordinator contacted the pilot directly regarding SAR missions."

According to Hassell, she was the fifth person to hold her position at AWT in five years -- which made her look into the underlying cause.

"(W)hen she asked why there had been so much turnover, she was told that it was 'because of the money. The position doesn't pay enough,'" NTSB officials wrote. "However, she found out over time that this was not the reason why people left; it was because the position 'doesn't have any authority.'"

In Hassell's view, the gaps in oversight at DPS were being filled by direct orders from higher authorities.

"(Hassell) explained that, in the section's Aircraft Operating Manual (AOM), 'it says in many places that the aircraft supervisor does this, or the aircraft supervisor does that,'" NTSB officials wrote. "(H)owever, 'that's not true. Actually, headquarters directs or makes a decision on those things even though it says in the manual that the supervisor does.'"

In addition to the discrepancies within the aircraft section, Hassell reported efforts to remove some AWT personnel from the section entirely.

"(Hassell) said that, within the past year, a couple of pilot positions were taken out of the aircraft section and assigned to AST detachments," NTSB officials wrote. "She thought this was a 'bad idea' because there would be no oversight of those pilots regarding aircraft section policies and procedures. She said she wrote a strongly worded email to everyone in the chain of command expressing her opinion and that the response she received was 'that's just what's happening.'"

As an example of the new policy's effects, Hassell offered a case in which she tried to give an order to someone in the field.

"The organization chart showed that (Hassell) supervised a pilot located in Bethel, Alaska, and she contacted the detachment commander and said that she needed the pilot to come to Anchorage for training," NTSB officials wrote. "The detachment commander replied that the pilot could not come and told the section supervisor that the pilot 'belonged' to the detachment and that he was the one who supervised the pilot."

Hassell retired from AWT on March 8, weeks before the deadly Helo-1 crash. Right up until her departure, she said she saw violations of procedure at DPS.

"A couple of weeks before she gave notice that she was leaving, a trooper pilot nosed over a Piper PA-18 Super Cub at a remote site; he and his supervisor, neither of whom was an airframe and powerplant mechanic, changed the propeller; and the trooper pilot then flew the airplane back to his base," NTSB officials wrote. "She said that this was an example of the fact that certain pilots could just do what they wanted and did not have to follow policies and that it was this specific instance that prompted her to give notice."

In a Monday interview with Channel 2, AST's current director, Col. James Cockrell, says NTSB investigators have already made some recommendations to improve safety culture within the department's aircraft section.

"They highlighted some areas that, based on their investigation -- that even though it may not have been the cause of the accident -- that we should look at," Cockrell said.

Cockrell says those changes include appointing a new commander of the aircraft section.

"We've put a new commander in place -- again as a commissioned lieutenant that has a strong background in aviation and aviation safety," Cockrell said. "And we're in the process of hiring a safety analyst or safety officer for our aviation program."

Other changes currently in effect at the department include different flight minimum restrictions for pilots, as well as halting the use of night-vision goggles in helicopters.

"We're actively engaged in talking to the NTSB, and we're taking every recommendation that they've made seriously at trying to implement everything within our power -- to ensure that we continue to fly safe, ensure the people of Alaska have trust in our pilots, and allow us to continue to do our important mission to servicing the citizens of the state," Cockrell said.

At the NTSB, Johnson says the story isn't finished, with the materials released so far only part of a factual report revealing the board's information. Another report, stating probable cause for the crash, is still pending.

"We're not done -- there are other documents that will be added to this docket," Johnson said. "We're shooting for midsummer to late summer as far as a final report, but that depends on what comes in."

Channel 2's Dan Carpenter and Garrett Turner contributed information to this story.