Chronicle of a chief: Retired, but not tired
Retired U.S. Air Force Chief Master Sgt. Mark Flockhart selects a lens to insert into a peripheral vision-testing machine at Langley Air Force Base, Va., Nov. 10, 2014. Flockhart is approaching 60 years of combined active duty and civil service to the U.S. Air Force. (U.S. Air Force photo by Airman 1st Class Devin Scott Michaels/Released)