Complex sentence: The 1st Battalion, 131st Aviation Regiment is an Army helicopter battalion that deployed to Iraq in September 2006 as a subordinate unit of Task Force Mustang to be a part of the US military Operation Iraqi Freedom.
Split into simpler sentences: The 1st Battalion, 131st Aviation Regiment is an U.S. Army helicopter battalion. It deployed to Iraq in September 2006 as a subordinate unit of Task Force Mustang to be a part of the US military Operation Iraqi Freedom.