Jerry Freed, 66, reported mechanical problems Friday morning shortly before the craft plunged into the lake several miles off the Michigan coast, Mason County Undersheriff Tom Trenner said. Freed was rescued and in good condition at Memorial Medical Center of West Michigan.
Freed and his passengers are residents of Alma, about 150 miles northwest of Detroit, where friends and relatives were praying for their safe return.
"We're crazy trying to figure out what might be going on," said Tony Costanzo, the school board vice president. "Some of the best people in town were on that plane."
An air and marine search continued for co-pilot Earl Davidson, Alma schools' superintendent Don Pavlik, his wife, Irene, and Dr. James Hall.
Don Pavlik was diagnosed earlier this year with cancer of the esophagus, and Freed and Davidson had volunteered to take him to the Rochester, Minn., medical center, Costanzo said. Hall, he said, came along because he wanted to help his ailing friend.
Freed's wife, Carol, told The Associated Press her husband and Davidson regularly flew people to Mayo on a volunteer basis. The Freeds owned the plane.
"We've all been to Mayo Clinic for various reasons," Carol Freed said. "A lot of people cannot get a flight there due to time constraints and cost."
The plane took off about 9 a.m. Friday from Gratiot Community Airport south of Alma, said airport assistant manager Lucas Locke. Carol Freed told the Ludington Daily News her husband had checked the plane Thursday in preparation for the trip and had no concerns.
The aircraft went down around 10 a.m. Jerry Freed was rescued by one of numerous boats that rushed to the scene.
Randall Schmidt of Park Ridge, Ill., who was on his boat with his wife, Kristin Berg, said he heard a marine radio call about the plane going down nearby.
"We had made one pass south, one pass north and we were about to turn back south when my wife ... saw a man in a yellow inflatable lifejacket close to our boat," Schmidt told the Ludington Daily News.
Schmidt said Berg threw a life ring to Jerry Freed and brought him aboard to wait for the local sheriff's department marine unit.
Water temperatures and conditions will have a lot to do with whether other survivors are found, Ludington Coast Guard Station Chief James Hendricks said. Waves in the area of the crash were 2 to 4 feet high, and the wind speed was about 18 mph. Hendricks said the temperatures likely were in the 70s.