U.S. Air Force Staff Sgt. James Terrell, left, and Senior Airman Bobby Chambers, students attending the Engineering Installation vehicle training class, guide a maintenance hole cover in place Dec. 13, 2017, at the Air National Guard Schoolhouse, Fort Indiantown Gap, Pennsylvania. Airmen utilized rigging techniques they learned in class to maneuver maintenance holes for underground installation. (U.S. Air National Guard photo by Staff Sgt. Tony Harp/Released)