"He goes to Mexico a lot with Doctors Beyond Borders and those types of organizations; so he does of a lot of voluntary support," Rand Kriech said.
Kriech says his business partner Dale Smith is not only chartable and generous, but also a good pilot who's been flying for years.
"The fact that that beacon did not go off, that's a positive sign that it wasn't a hard impact. So hopefully, he's just laid down somewhere and doesn't have any cellphone contact out there in the middle of nowhere," Kriech said.
Kreich said maybe the plane made a soft landing and that everyone was alright.
Earlier Tuesday, a ray of hope emerged -- a rescue plane detected something.
"Rescuers were able to pick up a very weak EOP transmitter broadcast from the downed aircraft," sheriff's spokesperson Robert Feeley said. "This helped them narrow the area which they're searching."
But searchers were unable to find the plane.
Kriech says Smith was flying a six-seat single-engine plane from Oregon to Butte, Montana with his oldest son Daniel and his wife Sheree, and his daughter Amber with her fianc? Jonathan Norton. Smith reported engine trouble and asked controllers for coordinates to the Johnson Creek Airstrip in the backcountry of Idaho -- but the plane never landed there.
Smith and his family had just spent thanksgiving at his parents' home in Oregon.
"He was just taking his son and his daughter back; his son back to Butte, Montana and his daughter back to Rexford, Idaho where she goes to school with her fianc?," Kriech said.
After dropping them off, Smith was going back to Oregon to pick up his wife and his other daughter and two younger sons and bring them back home to San Jose.
Matt Keller contributed to this report.