U.S. Air Force Senior Airman Kostiantyn Khymchenko, 633d Civil Engineer Squadron heating, ventilation, air conditioning journeyman, performs preventive maintenance on an igniter and flame sensor at Joint Base Langley-Eustis, Virginia, July 25, 2023. Preventative maintenance is routinely performed on the boilers, ensuring continuous hot water supply throughout the installation. (U.S. Air Force photo by Airman 1st Class Mikaela Smith)