The Maine Army National Guard plans a ceremony to mark completion of its Army Aviation Support Facility. The ceremony will be at 3 p.m. today at the facility’s site, 92 Hayes St. The facility will be home for the 112th Medical Company, or Air Ambulance, the Operational Support Airlift, or OSA, Command, the 1-224th Aviation and the 3-142nd Aviation. The 112th Medical Company provides air medical support to the state and military units.