A preliminary report has revealed the final moments of the July 26 plane crash that killed gospel band The Nelons.

The National Transportation Safety Board released its report Aug. 28, nearly a month after the crash claimed the lives of six passengers and the pilot, three of whom were members of the Gospel Music Association Hall of Fame quartet.

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

“One witness near the crash site heard a ‘loud groaning sound’ that gradually faded and then grew louder, and smoke began billowing from the crash site shortly thereafter,” the report reads. “Another witness observed an aircraft overhead performing a ‘barrel roll’ and heard a ‘loud roar’ from the aircraft engine until the aircraft hit the ground. The witness stated that he saw smoke in the area shortly thereafter.”

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

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

The Nelons co-founder Kelly Nelon Clark, her husband Jason Clark and their daughter Amber Nelon Kistler were killed in the crash, according to a statement from their daughter and fourth member, Autumn Nelon Streetman.

“Thank you for the prayers that have already been extended to me, my husband Jamie and our future son, 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 days ahead.”

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

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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 were traveling to join the Gaither Homecoming Cruise back to Alaska. Autumn, who was not traveling on the plane with her parents and sister, arrived safely in Seattle at that time.

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

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

Before the single-engine Pilatus PC-12/47E turboprop crashed, Dr. Alan Diehl, former NTSB, FAA and U.S. Air Force crash investigator, aviation psychologist and author of Requiem for Camelot, described in an interview with Fox News Digital what the passengers on the ill-fated flight may have experienced.

“Dark terror. That’s what you usually hear in my novel when I talk about (John F. Kennedy Jr.) falling out of the sky,” Diehl shared. “I said it was all over but the screaming, and this is based on the fact that he didn’t have a recorder on his plane, but I’m sure he and his two passengers were just terrified as the plane fell out of the sky, much like this one.”

“But of course in this case, you know, how the breakup happened, we don’t know — the plane could have lost pressure. And in a way — if the breakup happened early enough and they lost pressure, they could have been unconscious or semiconscious at the last moment. And that would be merciful. They would say it’s God’s mercy.”

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Tracy Wright of Fox News Digital contributed to this report.