year, Bell was contracted with upgrading 101 AH-1Gs to the TOW-capable AH-1Q configuration. While early-production examples were not compatible with night vision goggles, the cockpit instrumentation of later Cobras was altered to facilitate their use. Further variants of the Cobra were promptly developed, with both new-build models and early production examples being modified to incorporate the improvements. During March 1978, the US Army opted to procure a batch of 100 new-build Cobras that featured a new T-shaped instrument panel, improved composite rotor blades, revised transmission and gearboxes, the M128 helmet-mounted sight, and the M28A3 armament system. A major feature was the adoption of the more powerful T53 engine. Designated AH-1S, the Cobra was upgraded in three stages, culminating with the AH-1F. The AH-1F integrated numerous countermeasures, including an infrared jammer, a radar jammer, and a hot plume exhaust suppressor. The U.S. Marine Corps (USMC) quickly became interested in the Cobra, opting to order an improved twin-engine version in 1968 under the designation AH-1J. During the early 1970s, the USMC proceeded to order an upgraded model, the AH-1T, which featured dynamic elements derived from the abortive Bell 309 KingCobra; as such, it featured a longer fuselage and tailboom. These dynamic changes were combined with the adoption of heavier armaments, which provided the USMC with an effective anti-armour capacity, unlike the preceding model. The USMC's interest in the Cobra would lead to the production of more twin-engine variants of the helicopter. Design The Bell AH-1 Cobra is a dedicated attack helicopter, built to provide close air support and to escort friendly troop transports. The visual design of the Cobra was intentionally made to be sleek and be akin to that of a jet fighter. Aviation author Stanley McGowen observed that its appearance differed radically from any prior rotorcraft designed by Bell, possessing a relatively narrow fuselage and a then-unusual cockpit arrangement. This cockpit was covered by a large fighter-like canopy and its occupants protected by armor, such included tempered-steel seats and personal body armor. It was operated by both a pilot and gunner, who were seated in a stepped tandem arrangement in which the commander was placed in the rear seat while the gunner occupied the forward position. This forward position provided a higher level of visibility to that of the rear seat. Both positions were provided with flying controls while both crew would typically be certified pilots, enabling control of the