Complex sentence: HC-130s were assigned to the Air Combat Command (ACC) from 1992 to 2003; prior to 1992, they were assigned to the Air Rescue Service as part of Military Airlift Command (MAC).
Split into simpler sentences: HC-130s were assigned to Air Combat Command (ACC) from 1992 to 2003. Previously, they were assigned to the Air Rescue Service as part of Military Airlift Command (MAC).