UH-60 Black Hawk helicopter pilots for 2nd Battalion, 501st Aviation Regiment, 1st Combat Aviation Brigade, 1st Armored Division, deployed as Task Force Iron Knights, perform shutdown procedures after a night vision goggle reset flight at Spriggs Payne Airfield, Monrovia, Liberia, during Operation United Assistance, Jan. 24, 2015. NVG reset flights are required at a minimum every 60 days for flight crews to be allowed to conduct night flights with night vision goggles. The Iron Knights pilots maintain proficiency in order to execute any mission within the Joint Forces Command – United Assistance area of operations. 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)