Nondestructive inspection technicians ensure aviation safety Published Sept. 13, 2011 By Senior Airman Adam Grant 51FW Publilc Affairs OSAN AIR BASE, Republic of Korea -- Nondestructive inspection technicians from the 51st Maintenance Squadron perform tests to detect discontinuities in aircraft parts, Sept. 13, 2011. The technicians use a special oil-based dye called penetrant to perform these tests. The parts are dipped in the penetrant, rinsed and dried, and then put under an ultraviolet light to detect surface cracks. (U.S. Air Force Photos by/ Senior Airman Adam Grant)