UH-60 Black Hawk helicopter pilots with 2nd Battalion, 501st Aviation Regiment, 1st Combat Aviation Brigade, 1st Armored Division, deployed as Task Force Iron Knights, put their aircraft to bed for the night while crew chiefs conduct preventive maintenance dailies, ensuring the helicopter is fit to fly for the next mission at Spriggs Payne Airfield in Monrovia, Liberia, during Operation United Assistance, Jan. 24, 2015. The Iron Knights air crews fly numerous missions across the Joint Forces Command – United Assistance area of operations in support of OUA. Operation United Assistance is a Department of Defense operation in Liberia to provide logistics, training and engineering support to U.S. Agency for International Development-led efforts to contain the Ebola virus outbreak in western Africa. (U.S. Army photo by Sgt. Jose Ramirez, 1st Combat Aviation Brigade, 1st Armored Division Public Affairs/RELEASED)