Senior Airman Brandon Wilkins, 28th Aircraft Maintenance Squadron crew chief, inspects a B-1 bomber's landing gear during a Phase II operational readiness exercise on the flightline at Ellsworth Air Force Base, S.D., July 10, 2013. Aircraft must pass a series of tests, known as a pre-flight inspection, before they can be generated for real-world contingencies or OREs. (U.S. Air Force photo by Airman 1st Class Ashley J. Thum/Released)