ELLSWORTH AIR FORCE BASE, S.D. -- Senior Airman Adam McCary, 28th Civil Engineer Squadron electrical power production journeyman, pulls out a winch that blocks a roller sheave on a mobile aircraft arresting system, Oct. 15. Airman McCary removes the roller sheaves during a maintenance checkup which occurs every three years on the MAAS. (U.S Air Force photo/Airman 1st Class Anthony Sanchelli)