(CNN) -- The civilian pilot of an Arizona sheriff's department helicopter died Monday afternoon when the aircraft crashed in mountainous terrain, a Pima County Sheriff's Department spokesman said.
Loren Leonberger was pronounced dead at the scene, Deputy Jason Ogan said.
Three passengers survived the crash and were brought to University Medical Center in Tucson, Ogan said, but the full extent of their injuries was unknown. The crash happened about 11:30 a.m., he said.
Leonberger, a helicopter pilot veteran from the Vietnam War and the Army National Guard, joined the Pima County Sheriff's Department as a pilot in 2008, Ogan said, after serving in the same position with Maricopa County for a decade.
He flew with the state Department of Public Safety Air Rescue Unit for 20 years before retiring in 1998, Ogan said.
Video from CNN affiliate KNXV showed the blue and white helicopter lying on a mountainside. Rescuers lifted to the site by another helicopter were on the scene examining the wreckage as emergency crews stood by below.