From the 142nd Fighter Wing, Portland, Oregon, Airman 1st Class Brian Perkins, 142nd Maintenance Group F-15 crew chief, takes an oil sample following a Combat Archer sortie at Tyndall AFB, Florida, Jan. 29. Combat Archer is a two-week weapon systems evaluation program where participants load, fly and shoot live missiles and subsequently evaluate the entire process to validate whether the weapon performs according to established specifications. (Air Force Photo Released/Mary McHale)