Clifton Curtis "C.C." Williams Jr. (September 26, 1932 – October 5, 1967) (Major, USMC), was an American naval aviator, test pilot, mechanical engineer, major in the United States Marine Corps, and NASA astronaut, who was killed in a plane crash; he had never been to space. The crash was caused by a mechanical failure in a NASA T-38 jet trainer, which he was piloting to visit his parents in Mobile, Alabama. The failure caused the flight controls to stop responding, and although he activated the ejection seat, it did not save him. He was the fourth astronaut from NASA's Astronaut Group 3 to have died, the first two (Charles Bassett and Theodore Freeman) having been killed in separate T-38 flights, and the third (Roger B. Chaffee) in the Apollo 1 fire earlier that year. The aircraft crashed in Florida near Tallahassee within an hour of departing Patrick AFB. Although he was never on a spaceflight, he served as backup pilot for the mission Gemini 10, which took place in July 1966. Following this mission, he was selected to be the Lunar Module pilot for an Apollo mission to the Moon commanded by Pete Conrad. Following Williams' death, Alan Bean became Lunar Module pilot for Conrad's mission, which ended up being Apollo 12, the second lunar landing.