Military version of the Convair 240/340/440 series of twin-engine commercial airliners. The first Samaritan, a C-131A derived from the Convair 240, was delivered to the Air Force in 1954. It was primarily used by the USAF for aeromedical casualty evacuation. The C-131A had large loading doors for stretchers or cargo and was equipped to accommodate 27 stretchers or 37 sitting casualties. In later years, some Samaritans were converted to be used as VIP staff transports under the designation VC-131H.
Nearly all of the USAF's C-131s left the active inventory in the late-1970s, with a few still serving in Air National Guard units until the mid-1980s.
Note: The first prototype of the Southeast Asia vintage side-firing gunship program used the C-131 airframe.