A faint emergency locator transmitter signal gave crews hope as it was traced Tuesday to an area south of the Johnson Creek airstrip, near Yellow Pine, Idaho. But on Wednesday, other aircraft searching the same area could not pick up the signal.
"The teams are expanding their search as that signal may be misleading due to the mountainous terrain and the unreliable nature of the signal," according to a Valley County press statement Wednesday evening.
Aboard the missing six-seat, early 1980s model BE-36 Beech Bonanza were the pilot, Dale Smith; along with son Daniel Smith and his wife, Sheree Smith; and daughter Amber Smith with her fiancé, Jonathon Norton.
Norton's uncle, Alan Dayton, said his nephew and fiancé were both from the Salt Lake City area and both attended BYU-Idaho. They planned to marry on Jan. 4.
Dale Smith lives in South San Jose and is president of a Silicon Valley company, according to the San Jose Mercury News.
In all, 60 searchers were on scene Wednesday, an effort that included five Civil Air Patrol fixed wing aircraft and two Idaho National Guard helicopters.
Dayton, said the families of the missing were pleased with the "all-out effort" to find their loved ones, even as their hopes for a happy ending were fading.
"It's been 9-below out there and four days now," Dayton said Wednesday afternoon. "With this weather, there's just not much time left if we expect to find them alive."
Dayton said his nephew traveled from San Jose to Baker City, Ore., with the Smith family and they were en route to Butte, Mont., to drop off Amber Smith's brother and sister-in-law when the plane developed engine trouble Sunday afternoon and went missing.
Dale Smith had called air traffic controllers at Salt Lake City International Airport seeking coordinates to make an emergency landing at the Johnson Creek air strip near the Frank Church-River of No Return Wilderness Area. Shortly thereafter, the aircraft disappeared from radar.
"It's hard to think straight," David Christensen, whose daughter-in-law is pilot Dale Smith's oldest daughter, Crystal.
Christensen told the San Jose Mercury News that the Smiths were a tight-knit family, many of whom gathered Tuesday near where the plane lost contact, including Smith's wife and Michael and Crystal Christensen.
"We love our daughter-in-law so much, and we love their family," he said of the Smiths, whom he called "an amazing family" that is "extremely active."
"We are proud to be related to them," he said. "They're good people, a good influence. They do lots of things together. They play together, work together."
Christensen, who is a San Jose native but now lives in Draper, Utah, said the Smiths were in Oregon for the Thanksgiving holiday weekend before Sunday's flight.
Smith is president of San Jose data storage company Serialtek. Rand Kriech, who cofounded the company, told the San Jose Mercury News that colleagues are "very concerned" and they are "all waiting to hear news."
He said Smith bought the airplane in 2005 and has been flying ever since. Kriech said he has flown with Smith on occasion.
"He's a very safe pilot," Kriech said. "Very cautious."
Smith obtained his pilot's license in 2005 and has a second-class medical certification, allowing him to operate commercial aircraft.
As part of Wednesday's search, aircraft were flying grid patterns over the area in question, authorities said.
Also, the Civil Air Patrol was using forward-looking infrared radar in the search specialized equipment brought in from Wyoming that detects ground temperatures and can pick up anomalies, such as sunlight reflecting off metal.
Authorities said they continued to seek a faint emergency locator transmitter signal thought to have been picked up Tuesday, but the signal could not be verified by other aircraft searching in the same area Wednesday. Because the search may be misleading due to the mountainous terrain and the unreliable nature of the signal, the teams were expanding the scope of the search, authorities said.