U.S. Air Force Tech. Sgt. Alejandro Castillo provides overwatch for a patrol checking on the validity of a possible improvised explosive device during a field training exercise, June 24, 2009, on Wheeler Army Airfield's East Range, Hawaii. U.S. Air Force Tech. Sgt. Alejandro Castillo provides overwatch for a patrol checking on the validity of a possible improvised explosive device during a field training exercise, June 24, 2009, on Wheeler Army Airfield's East Range, Hawaii. SHARE: Download: Full Size (1.33 MB) Tags: Photo Essays Credit: VIRIN: 896749-J-ADP13-030.jpg Photo Gallery