The search continued Thursday for a missing airplane and a couple onboard outside of Truckee.

The single-engine airplane left the Truckee-Tahoe Airport just before 4 p.m. on Monday, April 17. The plane was headed for the Petaluma Municipal Airport, but family members say the aircraft never made it to the location.

Santa Rosa resident Brenda Richard was flying the blue and white Socata TB-20 Trinidad with her husband Mark Richard onboard.

Due to weather conditions the previous evening, the search began the morning of Tuesday, April 18, according a spokesperson from the Civil Air Patrol (CAP).

Ground crews searched the ramps at the Nevada County Airpark in Grass Valley, the Blue Canyon Nyack Airport near Emigrant Gap, and Nervinoe Airport near Beckworth, but found no sign of the missing aircraft.

Using radar analysis and cellular phone forensics, CAP and the U.S. Air Force Rescue Coordination Center narrowed the search down to an area located near Yuba Pass Road between Webber Lake and Jackson Meadows in Eastern Sierra County, according to a statement from the Sierra County Sheriff’s Office.

As reported earlier this week, the plane is equipped with an emergency location transmitter, but no signal has been sent.

The Sierra County Sheriff’s Department Search and Rescue team is part of the search, according to a statement from their office. Members of the U.S. Forest Service, the Civil Air Patrol, the Nevada County Sheriff’s Department Nordic Team, and the California Highway Patrol are also involved in the effort to find the plane and its missing passengers.

A spokesperson from the California Office of Emergency Services (Cal OES) confirmed Thursday that Cal OES is also working with search rescue personnel, and coordinating support from the National Guard.