Senior Airman Graham Willis and Staff Sgt. Ferdinand Brown, 77th Aircraft Maintenance Unit engine mechanics, observe an engine run up of an F-16 Fighting Falcon here, July 16. During the run up, the mechanics stay vigilant for faulty parts and, after the run up, will fix them on the spot. Going back and forth from full afterburner to idle puts stress and varying power levels through the jet and tests the computer in the cockpit with the jet's physical responses. Airman Willis and Sergeant Brown are both deployed from Shaw Air Force Base, S.C.