US Air Forces in Europe, Security Policeman, SENIOR AIRMAN Vance Burke is evaluated by an instructor, as he gives chase to a simulated intruder, during the Base Response portion of Exercise DEFENDER CHALLENGE 2000, at Lackland Air Force Base, Texas. Defender Challenge is the annual Air Force wide competition sponsored by Air Force Security Forces and showcases the talents and capabilities of 13 international Security Forces teams in seven physical fitness events, base defense, and policing skills over a period of 6 days