Tech. Sgt. Kevin Richmond of Whiteman Air Force Base, Mo., and Master Sgt. Chris Liszewski of the Maryland Air National Guard establish a plumb line from the rear landing gear to make an "x" on the floor while Master Sgt. Lewis Godfrey of the Air Force Reserves looks on. They do this on both of the rear gears and place a chalk line between the marks as part of the balancing an aircraft. (U.S. Air Force photo/Robert Fox)