The Convair C-131 Samaritan is an American twin-engine military transport produced between 1954 and 1956. The Samaritan is in fact the adaptation to the needs of the USAF of the civilian twin-engine Convair 240 and 340. It was the first twin-engine pressurized transport ordered by MATS and the first transport aircraft converted into an anti-guerrilla warfare aircraft. It was also used by the US Navy under the designation R4Y before 1962. (Sources Wikipedia)