The plane, a 1963 Mooney M20C aircraft that was reported missing on Saturday, was spotted Monday morning by the Park County (Wyo.) sheriff's search and rescue team on the eastern slope of Howell Mountain.
The condition of the two brothers who were flying in the craft is still unknown because rescuers have been unable to reach the crash site.
The two - identified earlier as Ward H. Zimmerman, 86, of Seattle and his brother Robert, 84, of Huntsville, Ala. - were on a cross-country trip when their plane disappeared.
Lance Mathess of the Park County Sheriff's Office said the aircraft is settled in a steep ravine at about 9,900 feet in elevation with a large cornice of snow above it. The plane has heavy front end damage and one wing has been torn away.
A rescue helicopter was able to land two searchers on top of Howell Mountain, Mathess said, but tests found that the snowpack directly above the wreckage was extremely unstable and that the risk of an avalanche was too high to attempt to reach the plane.
A Black Hawk helicopter has been requested and is en route to the area from the Air National Guard base in Cheyenne, Wyo. Once it reaches the scene, options will be discussed that include possibly lowering rescuers down to the wreckage to determine the condition of the occupants, Mathess said.
The search for the missing brothers and their plane earlier was delayed by poor weather, but conditions improved enough Monday morning to resume searching.
Ramiro Rico, Zimmerman's grandson, said his grandfather left their Seattle home a couple months ago to go on a flying trip with his brother.
The two pilots were headed from Cody, Wyo., to Seattle with a stop in Twin Falls, Idaho, but they never arrived.
Family members said Zimmerman and his brother made many flights together - some as far as South America.