The rapid development of jet aircraft in the immediate post-war years seemed to promise the end of the use of piston-engined aircraft in combat. However, the local conflicts of the first decades of the second half of the 20th Century proved that it was too early to send the veterans into retirement. The war in Vietnam presented a number of unpleasant surprises to the US military command, one of which was the so-called "Ho Chi Minh Trail" - an extensive network of trails and small roads in southern Vietnam and Laos, through which there was a continuous supply of weapons for the Army of the National Liberation Front. Attempting to attack it from the air using jet aircraft became a fiasco - the small groups of rebels quickly disappeared, long before the approaching aircraft, and therefore the effectiveness of such missions for the US Air Force was near zero. Perhaps the only positive factor was the weakness of the rebel defense, or indeed the complete lack of it. Initially the old A-26 Invader attack aircraft was used to fight the guerrillas, immediately converted to the B-26K standard. The plane carried effective weapons, but its flight endurance was very limited, even with the use of external fuel tanks. So the idea was born, to equip transport aircraft with weapons to attack ground targets from the air. Transports could stay up in the air for a long time, and their big cargo compartments allowed for the installation of ample armament. The ideal type in every respect to perform such work was the veteran C-47 Dakota / Skytrain. In two of the rear window openings were fitted six-barreled Miniguns, and a third was installed in the space for the side door of the cargo compartment. The new aircraft received the AC-47 designation ('A' denoted that the type belonged to the category of attacking machines). AC-47D is the next modification of this aircraft. The crew consisted of two pilots, three or four gunners, a navigator and an air to ground co-ordinating officer. The first squadron of these aircraft was established in early 1965. Several machines were non-standard modifications, while others had already standardized weapons and gained the call sign 'Spooky', after the mythical ghost that suddenly appeared and fatally struck down their enemies. The first few months of using the AC-47 were quite successful; however, in early 1966 the rebels on the Ho Chi Minh Trail appeared with 37 mm anti-aircraft armament, which offered formidable defense against the gunships. In a short time six of these machines were lost, and in the following months the intensity of their use significantly decreased. The AC-47 gave way to more modern gunships, such as the AC-119 and the AC-123. But with the advent of the mighty giant AC-130 all the earlier gunships were instantly obsolete. They were transferred to the air forces of South Vietnam, Laos and Thailand, where they were used until the early 1970s, when, given the advanced age of the design, they were finally deleted from the inventories of those countries' air forces.