The collision of two small planes sent one of the aircraft plummeting into the mountains, killing one person, officials said.
The other aircraft, which had three people aboard, made an emergency landing at the Westlake Village Golf Course.
Both planes were Cessna single-engine aircraft, one of which departed from Santa Monica Airport, according to preliminary information from the Federal Aviation Administration.
The body of the pilot of the plane that crashed in the mountains was spotted Monday evening in rugged terrain near Mulholland Highway and Las Virgenes Road, the Los Angeles County Sheriff's Department said.
Rescue crews "identified the wreckage of a single-seat airplane with a single occupant who appears to be deceased," said sheriff's department spokesman Steve Whitmore.
Radar information indicated the two Cessna 172s collided about eight miles east northeast of Ventura about 2 p.m., FAA spokesman Allen Kenitzer said in a statement.
The plane that left Santa Monica Airport was making an engine test flight and heading east when it collided with the other aircraft, according to the FAA. The crash sparked a fire that was quickly knocked down after burning about an acre of dry brush, officials said.
The other Cessna ended up in the middle of the third fairway at Westlake Village Golf Course. The hard landing resulted in non-life-threatening injuries to the three people on board, L.A. County sheriff's officials said.
County fire officials and witnesses said the landing gear was still up when the plane came down. One of the people aboard complained of back pain and was taken to a hospital, according to authorities.
Golfer Aaron Jesse, 47, said the plane came in silently and hit the ground with a thud.
Jesse said the plane clipped a tree, which spun the aircraft around 180 degrees. Jesse marveled that the pilot seemed to land gently — taking out only four inches of grass and dirt.
"Finally being a bad golfer paid off," Jesse said. "I hit it in the trees to the right. They landed 50 feet to the left of us in the center of the fairway. All we heard was a thud and then he made a gentle bounce and slid down the center of the fairway, veering to the left."