Air rescue crews are searching Northern California mountains for a single-engine plane reported missing after it failed to land in Petaluma as scheduled.
The Santa Rosa Press Democrat newspaper reported the Socata TB-20 Trinidad with two people aboard left the Truckee-Tahoe Airport near the Nevada border Monday afternoon.
The white and blue four-seater, which features gold trim, is registered to William Sherlock of Santa Rosa, according to public documents.
Officials said passengers of the plane were reported to be pilot Brenda Richard and her husband, Mark Richard.
The plane was expected to land about 180 miles away at the Petaluma Municipal Airport north of San Francisco.
Family members reported the plane missing, and a search was started by the Civil Air Patrol, the all-volunteer civilian auxiliary of the U.S. Air Force.
Mark Madigan is a neighbor of the missing couple.
"It's a shock, an absolute shock to hear something has happened to them," he said.
Neighbors say the Richards are parents of four daughters, ranging in age from late teens to late 20s. The Richards are also grandparents.
The Madigans remember them as always busy and Mark as a car fanatic.
"He used to have a sports car," Madigan said. "It was an R-8, and he'd warm it up in the morning, and you could hear throughout the neighborhood. It was a rumble, and you know he was heading out."
Officials say the aircraft is equipped with an emergency locater transmitter, but crews have not picked up any signal.
On Wednesday, crews were said to be focusing their efforts in a mountainous region 18 miles northwest from where the flight departed.
NBC Bay Area's Terry McSweeney contributed to this report.