The first eight T-28 Trojans reached Vietnam in March 1958, being handed over by the USA to the small South Vietnamese Air Force, which had been formed officially on July 1, 1955 as successor to the collaborationist air force set up by the French during the last phase of their stay in Southeast Asia. The planes were used for training pilots, as were the other 30 delivered to the VNAF at the same time as the first USAF unit to arrive in Vietnam, namely the 4400th CCTS (Combat Crew Training Squadron), which from October 20, 1961 was given the job of teaching the new South Vietnamese recruits. The 4400th Squadron was equipped with eight T-28s, four SC-47s and four RB-26s. But in 1962 Viet Cong pressure within the country began to make itself felt strongly, with ambushes on government columns and surprise attacks on villages and garrisons, so much so that it was considered indispensable to have aerial support ready to give assistance to the ground forces. At that point the T-28, because of the absence of true COIN (Counter Insurgency) aircraft, was transformed into the T-28D, with wing attachments for offensive purposes, in the form of bombs and rockets. In March 1962 the VNAF received another 30 of these; all were employed in action, sometimes even with a crew consisting of a South Vietnamese trainer pilot and an American instructor. Nevertheless the old and trusty Trojans proved well up to the new task and constituted the backbone of the strike forces of the VNAF up to 1964, when they were replaced by the Douglas A-1H Skyraider.