Three soldiers were killed in a U.S. Army National Guard helicopter crash in Mendon Wednesday night.According to the New York Army National Guard, a UH-60 medical evacuation helicopter was on a routine training mission when it crashed. According to the Monroe County Sheriff's Office, the crash happened around 6:30 p.m. in a field area near West Bloomfield and Cheese Factory roads in Mendon, approximately 20 miles south of Rochester. It is not yet clear what caused the crash. "This is a burden - a heavy, heavy burden - upon all of us," said Monroe County Sheriff Todd Baxter. "These are our freedom providers - and just showing again, freedom is not free. We lost three great Americans today." The three soldiers on board were assigned to 1st Battalion's C Company in the 171st General Support Aviation Battalion. The helicopter was based at the Army Aviation Support Facility at the Greater Rochester International Airport.