(CNN) -- A man who came across a fiery jet crash said he saw former Blink-182 drummer Travis Barker and disc jockey Adam "DJ AM" Goldstein trying to extinguish the flames on their bodies by ripping off their clothing.
DJ AM, left, and Travis Barker backstage at the MTV Video Music Awards on September 7.
1 of 2 "We turned to the jet to try and see if there was anything we could do, but immediately, there was nothing anyone could do," William Owens told CNN affiliate WIS in Columbia, South Carolina. "I felt ill or sick to think that these lives were snuffed out at that point."
The two men were in critical condition with extensive burns Saturday. The crash killed four other people on board, authorities said.
The Learjet 60 carrying six people, including Barker and Goldstein, was taking off from the Columbia Metropolitan Airport in South Carolina on Friday night when it went off the runway. The plane crashed through light towers and an antenna array before crossing a road and stopping at an embankment, authorities said.
Owens came across the plane wreck while driving and stopped to see whether he could help.
Lexington County Coroner Harry O. Harman said all the dead in Friday's crash were Californians.
He identified them as pilot Sarah Lemmon, 31, of Anaheim Hills; co-pilot James Bland, 52, of Carlsbad; Chris Baker, 29, of Studio City; and Charles Still, 25, of Los Angeles.
The Associated Press reported that Baker was an assistant to Barker and Still was a security guard for the musician.
Owens told WIS-TV he was driving on Highway 302 when he saw a fireball. Owens stopped and crossed across the road, which was doused with fuel, to get close to the wreckage.
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Barker was standing in the road, trying to extinguish his burning pants, Owens told WIS-TV.
Owens and Goldstein walked toward the plane, but there was nothing they could do to help, he said.
Federal investigators recovered the cockpit voice recorder from the crash site but said they aren't sure whether information on the device survived the blaze.
Investigators are also obtaining recordings of conversations between controllers in the tower and the jet's two-person crew, said National Transportation Safety Board spokeswoman Debbie Hersman.
"Air traffic controllers did observe sparks from the aircraft as it was going down the runway and immediately alerted fire-rescue crews at the airport," Hersman said Saturday evening in West Columbia.
The National Transportation Safety Board has sent team to West Columbia to investigate the crash.
The Learjet 60 crashed on takeoff at 11:53 p.m. Friday.
Beth Frits, spokeswoman at the Joseph Still Burn Center, in Augusta, Georgia, said Barker and Goldstein arrived at the hospital early Saturday. She said both men had "extensive burns." Watch charred wreckage of the plane »
Barker and Goldstein had played at a huge free outdoor concert in Columbia's Five Points district on Saturday night, CNN affiliate WIS-TV said.
Federal Aviation Administration spokeswoman Kathleen Bergen said the twin-engine private jet was cleared for takeoff on a flight to Van Nuys, California, and began its takeoff roll a few minutes before midnight.
Air traffic controllers "saw sparks coming from the runway -- whether that was from the aircraft or its engines, we don't know," Bergen said Saturday.
"They overran the end of runway 11. They impacted the antenna array and a number of lights at the end of the runway. They went through the perimeter fence and across the roadway here," Hersman said Saturday. "There was a significant post-crash fire."
The crash closed the airport, which is Columbia's main commercial and passenger terminal, and it remained closed late Saturday afternoon. The airport's Web site listed nine commercial airline flights canceled through 7 p.m. Saturday.
Hersman said the airport would not reopen until investigators finished collecting debris from the runway and crash site.
She said investigators would look at every aspect of the crash, from the pilots' schedules to the aircraft's condition. She said it was a fairly new airplane, manufactured in 2006 and certified to operate in 2007.
In addition to playing with Blink-182, Barker appeared in the MTV reality show "Meet the Barkers" along with his wife at the time, former Miss USA Shanna Moakler, according to MTV's Web site.