Tech. Sgt. Andrew Gravett, 437th Aircraft Maintenance Squadron crew chief, walks along the top of a C-17 Globemaster III while wearing a safety harness as he does a routine maintenance check of the aircraft June 4, 2013, at Joint Base Charleston – Air Base, S.C. The first C-17 to enter the Air Force’s inventory arrived at Charleston Air Force Base in June 1993. The C-17 is capable of rapid strategic delivery of troops and all types of cargo to main operating bases or directly to forward bases in the deployment area. (U.S. Air Force photo/Senior Airman Dennis Sloan)

Fog rolls across the Joint Base Charleston flightline as the sun rises above four C-17 Globemaster III’s June 4, 2013, at JB Charleston – Air Base, S.C. The first C-17 to enter the Air Force’s inventory arrived at Charleston Air Force Base in June 1993. The C-17 is capable of rapid strategic delivery of troops and all types of cargo to main operating bases or directly to forward bases in the deployment area. (U.S. Air Force photo/Senior Airman Dennis Sloan)

Fog rolls across the Joint Base Charleston flightline as the sun rises above A C-17 Globemaster III June 4, 2013, at JB Charleston – Air Base, S.C. The first C-17 to enter the Air Force’s inventory arrived at Charleston Air Force Base in June 1993. The C-17 is capable of rapid strategic delivery of troops and all types of cargo to main operating bases or directly to forward bases in the deployment area. (U.S. Air Force photo/Senior Airman Dennis Sloan)

Tech. Sgt. Andrew Gravett, 437th Aircraft Maintenance Squadron crew chief, walks along the top of a C-17 Globemaster III wing while wearing a safety harness as he does a routine maintenance check of the aircraft June 4, 2013, at Joint Base Charleston – Air Base, S.C. The first C-17 to enter the Air Force’s inventory arrived at Charleston Air Force Base in June 1993. The C-17 is capable of rapid strategic delivery of troops and all types of cargo to main operating bases or directly to forward bases in the deployment area. (U.S. Air Force photo/Senior Airman Dennis Sloan)

Fog rolls across the Joint Base Charleston flightline as the sun rises above A C-17 Globemaster III June 4, 2013 at JB Charleston – Air Base, S.C. The first C-17 to enter the Air Force’s inventory arrived at Charleston Air Force Base in June 1993. The C-17 is capable of rapid strategic delivery of troops and all types of cargo to main operating bases or directly to forward bases in the deployment area. (U.S. Air Force photo/Senior Airman Dennis Sloan)

Tech. Sgt. Andrew Gravett, 437th Aircraft Maintenance Squadron crew chief, walks along the top of a C-17 Globemaster III while wearing a safety harness as he does a routine maintenance check of the aircraft June 4, 2013, at Joint Base Charleston – Air Base, S.C. The first C-17 to enter the Air Force’s inventory arrived at Charleston Air Force Base in June 1993. The C-17 is capable of rapid strategic delivery of troops and all types of cargo to main operating bases or directly to forward bases in the deployment area. (U.S. Air Force photo/Senior Airman Dennis Sloan)