U.S. Air Force Airman 1st Class Luke Goins, 1st Maintenance Squadron precision measurement equipment laboratory apprentice, calibrates a weight and balance kit at Langley Air Force Base, Va., Aug. 18, 2015. The PMEL specialists use quantitative measurements to calibrate different measurement equipment and service approximately 5,000 parts. (U.S. Air Force photo by Senior Airman Kayla Newman/Released)