Crack inspection
Staff Sgt. Corey Fletcher, 100th Maintenance Squadron Fabrications Flight, non-destructive inspection specialist, looks over an X-ray film of an MH-53 Pave Low helicopter engine air particle separator June 20. NDI specialists detect structural flaws, cracks, defects and foreign object damage in aircraft parts by using X-rays and fluorescent green penetrant. The cracks are usually invisible to the naked eye, but the NDI team finds them and make sure affected parts are taken out of service immediately. (U.S. Air Force photo by Staff Sgt. Tyrona Pearsall)