Staff Sgt. Casey O’Neal, 944th Aircraft Maintenance Squadron crew chief, inspects the exhaust on an F-35 Jan. 29, 2018, Luke Air Force Base, Ariz. The inspections are required each time the engine has flown or been operated. O’Neal is an Air Reserve Technician attached to the 61st Aircraft Maintenance Unit, an active duty unit here. He was selected as the 944th Fighter Wing Warrior of the Month for the January unit training assembly. (U.S. Air Force photo by Staff Sgt. Lausanne Kinder/RELEASED)