One of the few aircraft designed from the start for tactical support, the A-37 arrived in Vietnam toward the end of the 1960s and was mainly used in support of helicopter operations. Capable of mounting a wide range of weapons, it proved highly adaptable to diverse operational needs. Particularly effective were its low-level napalm bomb attacks. A fairly limited number of machines, under the colours of both the USAF and the VNAF (the illustration shows the VNAF insignia), were used in action.

US Army

During the late 1950s the Army Aviation Test Board and the Aviation Combat Developments Agency (ACDA) began to jointly explore the feasibility of using Army-operated fixed-wing jet aircraft in the artillery adjustment, tactical reconnaissance, and ground attack roles. Operational necessity dictated that any such aircraft be easy to maintain under field conditions and capable of operating from unimproved forward air strips, and these prerequisites indicated that any jet procured for Army use would have to be simple and relatively small, yet at the same time be of robust construction and able to offer a performance significantly better than that of the various piston-engined machines then in Army service. Cessna's diminutive T-37 twin-engined primary trainer admirably fulfilled all these requirements, and in early 1958 three examples borrowed from the Air Force were sent to Fort Rucker to begin a one year Army evaluation programme dubbed Project LONG ARM.

US Army T-37

The Cessna Model 318 had been adopted by the Air Force as the T-37 after winning a 1953 USAF-sponsored design competition for a new primary jet trainer. The first of two prototype XT-37s had made its maiden flight in early 1954, and the first eleven production T-37As had entered USAF service in 1955. The three aircraft evaluated by the Army were all -A model machines of the fourth production batch, and carried the serial numbers 56-3464 to -3466. The T-37, widely if unofficially known as the 'Tweetybird', was characterized by low-set, non-swept wings, side-by-side crew seats, and a broad forward fuselage. The type was equipped with ejection seats for both crewmen, and its cockpit instruments and controls were identical to those found in frontline USAF aircraft. The T-37A was powered by two Continental J69 turbojets, one buried in each wing root, and was quite manoeuvrable and relatively easy to fly.

The Army's evaluation of the T-37 found the aircraft to be ideally suited for Army use and both the Aviation Board and the ACDA recommended quantity procurement of the type. However, mounting Air Force opposition to Army ownership and operation of fixed-wing jet aircraft eventually forced the Army to abandon the planned T-37 acquisition and all three machines used in the Project LONG ARM tests were returned to the Air Force in early 1959.

Technical Specifications