Lt. Cheryl MacWillie of the Los Angeles County coroner's office identified the victims Monday as the pilot, David Gibbs, 59, of Valencia, and passengers Michael Donatelli, 45, of Pennsylvania and Darren Rydstrom, 46, of Whittier, the Los Angeles Times reported.
"A production company was shooting a show for Discovery Channel when this tragic accident occurred," Discovery said in a statement. "We are all cooperating fully with authorities. Our thoughts and prayers go out to the families."
Eyeworks officials also expressed their "deepest sympathies to the families of those involved."
"We can confirm that a helicopter crash occurred this morning while shooting a new series for a cable network, which resulted tragically in three fatalities," Eyeworks said in a statement. "We are cooperating fully with the authorities."
The Bell 206 helicopter went down about 3:30 a.m. Sunday while a crew was shooting for a military-themed, unscripted show from Eyeworks at the Polsa Rosa Ranch at Acton, Variety reported.
The cause of the crash was being investigated.