Senior Airman Charles Nicholls, a crew chief assigned to the 355th Aircraft Maintenance Squadron, Davis-Monthan Air Force Base, Ariz., performs pre-flight inspections on an A-10 Thunderbolt II during Green Flag-West 15-03 at Nellis Air Force Base, Nev., Jan. 26, 2015. Specifically designed for close air support, its combination of large and varied ordnance load, long loiter time, accurate weapons delivery, austere field capability, and survivability has proven invaluable to the United States and its allies.