Rescue crews continued to scour the Sierra Nevada on Sunday as the search for a Santa Rosa couple and the single-engine plane they were piloting stretched into its sixth day. The Civil Air Patrol launched three planes Sunday morning to conduct visual and photographic searches of an area about 18 miles northwest of Truckee. The California Highway Patrol and the Air National Guard also have planes in the air to complement a ground search being led by the Sierra County Sheriff’s Office. According to the Sierra County Sheriff’s Office, the aircraft is equipped with an emergency locator transmitter, but no satellite hits have come from the plane’s beacon. “The Civil Air Patrol and U.S.