U.S. Air Force Senior Airman Johnathon Copeland, 99th Civil Engineer Squadron electrical power production apprentice, conducts scheduled maintenance on an Emergency Standby Generator during an annual inspection at Fire Station 3 Jan. 6, 2012, at Nellis Air Force Base, Nev. 99th CES power production Airmen provide maintenance for more than 60 generators on Nellis AFB. U.S. Air Force photo by Staff Sgt. Christopher Hubenthal.