U.S. Air Force Senior Airman Patrick Long, an Aircrew Flight Equipment (AFE) journeymen assigned to the 1st Operation Support Squadron, disassembles a MBU-20/P Oxygen Mask for a 30-day inspection at Langley Air Force Base, Va., Nov. 17, 2015. The AFE personnel use various types of equipment such as altimeters, oxygen testers, leakage testers and radio testers to conduct reliability tests. (U.S. Air Force photo by Staff Sgt. J.D. Strong II)