Senior Airman James Earnst (right), 37th Aircraft Maintenance Unit communication, navigation and mission systems journeyman, unscrews the control panel of a radar altimeter in a B-1 bomber while being supervised by Staff Sgt. Tim Burgett (left), 37th AMU communication, navigation and mission systems craftsman, during regular maintenance at Ellsworth Air Force, Base, S.D., Dec. 3, 2014. The radar altimeter provides a digital readout of an aircraft’s altitude combined with a discrete warning indicator which alerts the pilot when the aircraft drops below a pre-selected altitude. (U.S. Air Force photo by Senior Airman Hailey R. Staker/Released)