Federal Aviation Administration spokeswoman Elizabeth Isham Cory says the Cessna 206 left Alma Friday morning en route to Rochester, Minn. Alma is in central Michigan about 150 miles northwest of Detroit.
Parks says the crash was reported by a witness as well as a distress signal from the plane via satellite.
A map of the plane's flight path from flightaware.com suggests problems developed early in the flight. The plane changed course, but went down before reaching shore.
Just over three years ago, a University of Michigan medical plane crashed into Lake Michigan en route to Milwaukee.
That plane was also a single-engine Cessna. All six members of an organ transplant team aboard died in the accident.
Investigators say the pilot reported steering problems just before the Survival Flight disappeared from radar.
Dozens of people gathered for a prayer vigil at the city's United Methodist Church downtown.
Alma is tight community. Many people knew one person -- if not all of the people -- on the plane. Earlier Friday night they joined together to help each other cope.
"Its devastating for the whole town," said Jane Keon.
Don Pavlik and his wife Irene were like family to some of the people at the church. The pastor says sometimes they attended the church, but all five people on the plane were well known.
Community members say they are leaning on their faith to get then through these tough times.
