C-130 Hercules airplanes fly people and supplies all around the world supporting the military.
When they come home, workers at Robins Air Force Base repair each part including the four propellers onboard.
13WMAZ went Behind the Lines and into the vital mission of the prop shop.
About 100 people grind metal in Robins prop shop, but it's the only place in the entire Department of Defense this work happens.
"It's loud. It's very loud," Tracey Owens, a mechanic, said.
Owens and the other prop mechanics pump out about 30 props each month.
"We are an overhaul facility," Kyle Barrett, another prop mechanic, said. "We take it down to the bare metal."
"The props come in dirty and damaged," Barrett said. "These have probably been in Afghanistan, you know, the elements out there. Nothing but sandstorms."