Three men killed in a pre-dawn helicopter crash in Acton on Sunday have been identified.
The Los Angeles County Coroner has identified the victims as pilot David Gibbs, 59, of Valencia, 46-year-old Darren Rydstrom, of Whittier, and Michael Donatelli, 45, of Pennsylvania.
Autopsies were pending.
The crash occurred around 3:40 a.m. at the Polsa Rosa Ranch while the crew was taking part in the filming for a new reality TV show for the Discovery Channel in a rural area of northern Los Angeles County.
Los Angeles County Fire dispatcher Robert Diaz said everyone on board died.
"The helicopter, a Bell 206B Jet Ranger, crashed under unknown circumstances," Federal Aviation Administration spokesman Allen Kenitzer said.
Filming involving the use of a helicopter began Saturday.
"A production company was shooting a show for Discovery Channel when this tragic accident occurred," the station said in a statement. "We are all cooperating fully with authorities. Our thoughts and prayers go out to the families."
The cause and other circumstances surrounding the crash were still unknown, Federal Aviation Administration spokesman Allen Kenitzer said.
Records also showed that Crossbow Helicopters received approval to participate in filming from the Federal Aviation Administration.
According to its website, Polsa Rosa is a "movie ranch" where film crews can utilize a variety of terrains as well as two airstrips.
It was the site of another entertainment industry death in September, when a 48-year-old crew member died of an apparent heart attack while underwater in scuba gear on the set of the upcoming Johnny Depp film "The Lone Ranger."
Sunday's wreck was also just 25 miles from a similar rural spot in Santa Clarita where actor Vic Morrow and two children were killed in another helicopter crash while filming the "Twilight Zone" movie in 1982.
The permit indicated the production company is Redondo Beach-based company Bongo Inc.