High Quality Content by WIKIPEDIA articles! The Boeing YC-14 was a twin-engine short take-off and landing (STOL) tactical transport. It was Boeing`s entrant into the United States Air Force`s Advanced Medium STOL Transport (AMST) competition, which aimed to replace the Lockheed C-130 Hercules as the USAF`s standard STOL tactical transport. Although both the YC-14 and the competing McDonnell Douglas YC-15 were successful, neither aircraft entered production. The AMST project was ended in 1979 and replaced by the C-X program.