Senior Airman David Castillo-Collazo, 31st Maintenance Squadron Aerospace Ground Equipment journeyman, starts on a generator to perform a system check on equipment, Jan. 31, 2017, at Aviano Air Base, Italy. Instructors from the 372nd Training Squadron Detachment 24 teach Airmen advanced maintenance practices for real-life situations. (U.S. Air Force photo by Senior Airman Cary Smith)