Three members of the gospel group, the Nelons, were among seven people killed Friday, July 26, in a plane crash in Wyoming. There were no survivors.

An "autopilot issue during flight" was noted as a cause for concern by the National Transportation Safety Board spokesperson Keith Holloway, who also said that investigators were further evaluating the situation after investigating the crash site.

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. 

THREE MEMBERS OF GOSPEL MUSIC HALL OF FAME QUARTET, THE NELONS, AMONG 7 KILLED IN PLANE CRASH

46th Annual GMA Dove Awards - The Nelons

Jason Clark, Kelly Nelon Clark, and Amber Nelon Clark died in a plane crash in Wyoming. Autumn (second left) was not onboard the aircarft when it crashed. (Terry Wyatt/Getty Images for Dove Awards)

"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."

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. "We appreciate your continued prayers, love and support as we navigate the coming days."

"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."

— Dr. Alan Diehl

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.

ROD STEWART AWARE HIS 'DAYS ARE NUMBERED' AHEAD OF 80TH BIRTHDAY: ‘I’VE GOT NO FEAR'

Diehl said investigators on the ground will begin a "major effort to try to establish whether that particular autopilot failed." He added, "Theoretically, you have, whenever something like that fails, you have to tell the FAA about it so that they can start tracking this data."

The Nelons

Kelly Nelon Clark, Amber Nelon Thompson, Autumn Nelon Clark, and Jason Clark of The Nelons attend the 52nd GMA Dove Awards at Lipscomb Allen Arena on October 19, 2021 in Nashville, Tennessee.  (Jason Kempin/Getty Images)

He noted that when NTSB investigators arrived on scene, they likely looked to see if the bodies were "in the aircraft" or not, or even if clothes were on their bodies.

"If their clothes were off that means they were thrown out while the airplane was still falling," he said. "Your clothes, if you're coming down at two, 300 miles an hour, I don't care what you're wearing, unless it's really tight blue jeans, your clothes get ripped off."

LIKE WHAT YOU’RE READING? CLICK HERE FOR MORE ENTERTAINMENT NEWS

Diehl added, "I investigated military accidents and a lot of times the flight suits are even ripped off. They knew they were going to die for a couple of minutes."

Kathleen Bangs, an aviation safety expert and former airline pilot, told Fox News Digital that the Pilatus PC 12 is an "expensive airplane" which only requires one pilot to operate it. Unfavorable weather activity may have affected the flight, causing the plane to spin out of control.

Autumn Nelon Streetman

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)

CLICK HERE TO SIGN UP FOR THE ENTERTAINMENT NEWSLETTER

"People often ask were people conscious during this," Bangs said. "And you know, at 26,000 feet the air is quite thin. So there's always the chance that with the oncoming velocity of the air hitting you at 300 miles an hour, and all of a sudden the temperature is quite cold. The air is quite thin. There is a good chance that if occupants were ejected, that they would lose consciousness. 

"There are incidents where people have been conscious all the way down."

The Atlanta-based Gospel music family was en route to join the Gaither Homecoming Cruise to Alaska when the plane went down, cruise sponsor Gaither Music Group said. Autumn, the family's youngest daughter, and her husband, Jamie Streetman, were not on the plane and learned of the crash when they arrived safely in Seattle. 

"Autumn and Jamie will return home for now to Kelly’s brother, Todd Nelon and his wife, Rhonda, to begin the hard tasks that lie ahead. Please keep them, the Kistler family, the Haynie family and the family of Melodi Hodges in your prayers," Gaither Music Group said. 

CLICK HERE TO GET THE FOX NEWS APP

A preliminary report on the crash is expected in about 30 days, while a final report with the probable cause of the crash could take up to two years to complete, Holloway said.

The Nelons were inducted into the Gospel Music Association Hall of Fame in 2016 and were winners of 10 GMA Dove Awards, including multiple song of the year and album of the year awards.