A single-engine aircraft crashed Thursday afternoon about 1,000 feet from a regional airport in Sonoma County, killing one man and hospitalizing three other people, officials said.

The crash was reported at 12:46 p.m., when the plane went down near the sole runway of the tiny Sonoma Skypark Airport, just north of Highway 12 in Sonoma, said Ian Gregor, a spokesman for the Federal Aviation Administration.

The man who died was identified as San Francisco resident William Sachs Goldman, 38, by the Sonoma County Sheriff’s Office.

Goldman, an assistant professor at the University of San Francisco, was the grandson of the late well-known San Francisco philanthropists Richard and Rhoda Goldman.

USF President Paul Fitzgerald said the university community was devastated to learn of the death of Goldman, whom he called “an accomplished scholar, a beloved and generous teacher, and a valued member of our community.”

Richard and Rhoda Goldman were known throughout the United States for their philanthropic work, supporting a number of different movements with hundreds of millions of dollars in collective assets — including environmental and Jewish causes.

The single-engine plane, a Cirrus SR-22, which seats five people, crashed “under unknown circumstances” in a field about 1,000 feet west of the airport, Gregor said. Four people were on board when the plane went down, he said.

What caused the crash was not immediately clear — including whether the small plane may have crashed on takeoff or when attempting to land. Video from the crash scene taken by television news stations depicted a parachute among the wreckage.

The three injured passengers were taken to hospitals in unknown condition, according to a dispatcher with the Sonoma County Fire and Emergency Services Department.

Two of them were airlifted via helicopter to UCSF Benioff Children’s Hospital Oakland, the dispatcher said. A spokeswoman there could not immediately confirm their condition.

A third person was taken via ambulance to Sonoma Valley Hospital, the dispatcher said.

Michael Bodley is a San Francisco Chronicle staff writer. Email: mbodley@sfchronicle.com. Twitter: @michael_bodley