361st Training Squadron aerospace propulsion apprentice course students perform a prop control change at Sheppard Air Force Base, Texas, April 3, 2019. These propellers are usually on aircraft like the C-130 Hercules. The prop control is in charge of controlling the propellers position while in flight. If the prop control malfunctions there is a safety precaution that forces the propellers to feather allowing the pilot easier control while they prepare for an emergency landing. (U.S. Air Force photo by Airman 1st Class Pedro Tenorio)