Tech. Sgt. Andrew Arnett prepares to swap the #4 engine on a KC-135R Stratotanker aircraft.
U.S. Air Force Tech. Sgt. Andrew Arnett, with a maintenance squadron with the 117th Air Refueling Wing, prepares to swap the #4 engine on a KC-135R Stratotanker aircraft in Birmingham, Ala., on July 26, 2011.