A U.S. Air Force crew chief from the 67th Aircraft Maintenance Unit waits for an F-15 Eagle pilot to start an aircraft’s engine during annual exercise Cope North Feb. 20, 2017, at Andersen Air Force Base, Guam. The maintenance performed by Airmen around-the-clock is essential for keeping aircraft running safely and effectively. Maintenance Airmen also enable Pacific Air Force units, such as the 67th FS, to protect and stabilize the Indo-Asia Pacific. (U.S. Air Force photo by Senior Airman John Linzmeier/released)