A German Air Force maintainer performs pre-flight checks on a German Air Force CH-53GS during Angel Thunder 2015 at Davis-Monthan Air Force Base, Ariz., June 7, 2015. Angel Thunder is the world’s largest personnel recovery exercise. D-M hosted 11 partner nations and nine interagencies with a common goal to train personnel recovery forces to prepare, plan, execute and adapt for rescue missions. (U.S. Air Force photo by Airman 1st Class Chris Massey/Released)