Crew Chief Operations
Senior Airman Shaun Hover, a crew chief with the 191st Aircraft Maintenance Squadron is in communication with the crew aboard a KC-135 Stratotanker at Selfridge Air National Guard Base, Mich., Dec. 3, 2011, as he helps to prepare the aircraft for a mission. Crew chiefs perform and coordinate a wide variety of maintenance tasks and prepare the aircraft for flight. (U.S. Air Force photo by TSgt. David Kujawa)