Staff Sgt. John Cooke tests the maneuverability of an all terrain vehicle. U.S. Air Force Staff Sgt. John Cooke, assistant non-commissioned officer in charge of mobility for the 28th Security Forces Squadron, tests the maneuverability of an all terrain vehicle equipped with a rubber track conversion system at Ellsworth Air Force Base, S.D., on Jan. 6, 2009. The installation of the conversion system improves the snow rescue capabilities of the squadron. SHARE: Download: Full Size (0.08 MB) Credit: VIRIN: 570244-M-JST66-297.jpg Photo Gallery