Vermontville - Three people died Monday after a home-built, single-engine airplane crashed in a rural town, about 30 miles west of Lansing.

Though a positive identification could not be made, the victims appear to be a father and his two sons traveling from Ypsilanti to Billings, Mont., Eaton County Sheriff Rick Jones said.

The cause of the crash won't be known for months, as aviation officials work to put together the pieces leading up to the incident, said Anson Gray, one of two on-scene Federal Aviation Administration safety inspectors.

Gray said home-built planes are typically just as sound as commercially manufactured planes.

"The workmanship in this aircraft is excellent," Gray said of the leather-seated plane.

According to witnesses, the Lancair experimental aircraft was circling widely at about 1,500 feet, when it began losing altitude. Its circles became smaller until the plane eventually flattened out and appeared to regain control, said Roger Trowbridge - a local resident who saw the plane descend under the trees from his barn about one-half mile away.

When the craft did not reappear above the trees, Trowbridge knew it had gone down and immediately called 9-1-1, he said.

The plane apparently landed on the belly of the fuselage, which kept it intact, officials said.

The National Weather Service reported partly-cloudy skies and 18-mile-per-hour southwesterly winds at the time, though Trowbridge remembers a dark sky and gusty winds preceding the plane's descent.

Immediately following the incident, heavy rain began, he said.

The last time a plane crashed in Eaton County was in October 1997, said an Eaton County police officer on the scene.

"This is a very, very quiet area," said Jones. "It's usually nothing but wildlife out here. It was a very horrendous scene."