A glowing inspection
U.S. Air Force Airman Matthew Walker, 18th Equipment Maintenance Squadron nondestructive inspection technician, submerges a KC-135 Stratotanker wheel in fluorescent penetrant at Kadena Air Base, Japan, June 28, 2021. The fluorescent penetrant must coat the wheel for 30 minutes before moving on to the next step of the inspection. There are six steps to the penetrant inspection: pre-cleaning the part, applying the penetrant, removing the penetrant, applying developer, evaluating indications and post inspection cleaning. (U.S. Air Force photo by Airman 1st Class Yosselin Perla)