DELANO, Calif., Jan. 3 (UPI) -- Federal authorities said they are investigating a helicopter crash that killed a female pilot doing frost control work on crops near Delano, Calif.
The Bakersfield Californian said the helicopter was doing work on citrus groves before it dove into a grape vineyard outside Delano.
A police spokesman said the crash site was found at 9:50 a.m. Wednesday. The helicopter had been missing for more than three hours.
The spokesman said the search was hampered by low visibility and fog.
An official from the Federal Aviation Administration in Fresno is heading the investigation.
An FAA spokesman said the helicopter was returning to the airport when it disappeared.
The Bakersfield Californian reported San Joaquin Helicopters owns the helicopter.