A preliminary report revealed the final moments of the July 26 plane crash that left members of gospel group The Nelons dead.

The National Transportation Safety Board released the report on Aug. 28, nearly a month after the fatal crash took the lives of six plane passengers and the pilot. Three of the deceased were members of the Gospel Music Association Hall of Fame quartet.

The report revealed the pilot declared an emergency after the loss of autopilot and told the Salt Lake City Air Route Traffic Control Center controller he was trying to regain control of the aircraft. Witnesses also described the moments before and after the crash.

"One witness located near the accident site heard a ‘loud whining noise’ that diminished and then increased followed shortly thereafter by smoke emanating from the area of the accident site," the report read. "Another witness observed the airplane overhead in a ‘barrel roll’ maneuver and heard the airplane’s engine ‘roaring loud’ until they heard the airplane impact terrain. The witness stated that they saw the smoke in the area shortly after."

GOSPEL GROUP MAY HAVE SUFFERED ‘DARK TERROR’ IN FATAL PLANE CRASH THAT KILLED 7: EXPERT

The Nelons

The National Transportation Safety Board released a preliminary report on the plane crash that killed three members of The Nelons. (Jason Kempin/Getty Images)

The Nelons' co-founder Kelly Nelon Clark, her husband Jason Clark, and their daughter Amber Nelon Kistler died in the crash, according to a statement shared by daughter and fourth band member Autumn Nelon Streetman.

"Thank you for the prayers that have been extended already to me, my husband, Jamie, and our soon-to-be-born baby boy, as well as Jason’s parents, Dan and Linda Clark," she said at the time. "We appreciate your continued prayers, love and support as we navigate the coming days."

Amber's husband Nathan Kistler, their assistant Melodi Hodges, the pilot Larry Haynie, and his wife Melissa were also killed in the crash, according to Nelon Streetman.

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46th Annual GMA Dove Awards - The Nelons

Jason Clark, Kelly Nelon Clark and Amber Nelon Kistler died in a plane crash in Wyoming. (Terry Wyatt/Getty Images for Dove Awards)

The Nelons had been traveling to join Gaither Homecoming Cruise in Alaska. Autumn, who had not been traveling on the plane with her parents and sister, made it safely to Seattle at the time.

The preliminary report on the July 26 crash noted the information was "subject to change." A final report on the probable cause of the crash could take up to two years to complete, National Transportation Safety Board spokesperson Keith Holloway previously said.

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The Nelons at an awards ceremony

Autumn Nelon Streetman (right) was not on board the aircraft, which crashed and claimed the lives of her family members. (Jason Davis/Getty Images for GMA)

Prior to the single-engine Pilatus PC-12/47E turboprop airplane crashing, Dr. Alan Diehl, a former NTSB, FAA and U.S. Air Force Crash Investigator, Aviation Psychologist and author of, "Requiem for Camelot," described to Fox News Digital what the passengers on the fatal flight may have experienced.

"Dark terror. That's what you usually hear in my novel when I talk about [John F. Kennedy Jr.] falling from the sky," Diehl shared. "I said it was all over, but the screaming, and that's based on, you know, he didn't have a voice recorder on his airplane, but I'm sure that he and his two passengers were just in terror as the plane was falling out of the sky, much like this one."

"But of course, in this case, you know the actual breakup, we don't know — the plane may have lost pressurization. And in a way… if the breakup occurred early enough, and they lost pressurization, they may have actually been unconscious or semi-conscious at the last minute or so. And that would be merciful. They would say that was God's mercy."

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Fox News Digital's Tracy Wright contributed to this report.