WATERLOO, Ill. (AP) — Two adults and a 4-year-old boy were injured but survived a small plane crash in southern Illinois.

Authorities say the fixed-wing single-engine Piper PA-32 went down Tuesday afternoon in rural Monroe County while traveling from Mobile, Alabama, to St. Louis Downtown Airport in Cahokia, Illinois.

Monroe County Sheriff’s Major Jim Lansing says a 4-year-old boy and his grandmother and grandfather were aboard. He says they were talking and conscious when they were taken to hospitals for treatment of non-life-threatening injuries.

Lansing said the woman told authorities a warning light went on, oil was spewing onto the windshield and they couldn’t see.

The plane crashed in off-duty Waterloo police officer Trin Daws’ yard. He says he and an unidentified man broke the plane’s windows with a fire extinguisher and pulled the boy out.