The search is centered south of Yellow Pine, in very rugged terrain, but family and friends are not giving up hope.
The emergency locator transmitter that search planes picked up Monday is weak and it's not an exact science.
"You need to understand that this is a radio frequency and this is really mountainous terrain and so that frequency can bounce off those mountains in the surrounding area, which can complicate the identification of that location," sheriff spokesperson Robert Feeley said.
Employees of SerialTek, the company Dale Smith co-founded, are very worried and are monitoring all of the developments closely. The fear is that if Smith and his family did survive a crash landing, the longer it becomes, the less chance of surviving the elements.
On Wednesday, the search was expanded and about 60 people were combing the ground. Five fixed wing aircraft and two helicopters were in the air and they brought in high tech equipment to help pinpoint the plane's path.
"You don't want to give up hope. You just don't want to give up hope," said Rand Kriech, a co-founder of SerialTek.
Rand Kriech says if anyone can survive a plane crash and three nights in the frigid rugged wilderness, it would be his business partner, Smith.
"He's done all the Boy Scout stuff with the troops and with his children, so yeah I think he's the one that could survive something like this," said Kriech.
Smith was piloting his Beach Bonanza six-seater when it lost radar and cell tower contact Sunday in central Idaho. On board with Smith, his son Daniel and his wife, and Smith's daughter Amber and her fiancée, Jonathon Norton.
Norton was meeting his fiancés family over Thanksgiving.
We spoke to Alan Dayton, Norton's uncle, who said, "They are deeply in love. I got my wedding announcement a couple days ago, but they were scheduled to be married on January 4. The number one concern that we have is they survived the crash and they may be injured, but they're having to survive in 10 degrees weather at nighttime, possibly with snow coming down and no way to keep warm."
On Sunday, 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.
Command staff will meet Wednesday night to decide the status of the search on Thursday.