ELLSWORTH AIR FORCE BASE, S.D. -- Airman 1st Class Christopher Bratton, 28th Civil Engineer Squadron electrical power production apprentice, unscrews bolts to a roller sheave in order to remove them from a mobile aircraft arresting system, Oct. 15. Airman Bratton maintains and cleans the MAAS by removing all parts and pieces during a maintenance checkup, which occurs every three years. (U.S Air Force photo/Airman 1st Class Anthony Sanchelli)