Its procurement by the US military was initially controversial due to the high level of Canadian content, such as its Pratt & Whitney Canada PT6T turboshaft engines.

[1] The Twin Huey would see service in numerous conflicts, the first being the Vietnam War, where they were commonly used to support Special Forces reconnaissance missions.

In the 2010s and 2020s, multiple operators were in the process of replacing the Twin Huey with newer helicopters, such as the Bell UH-1Y Venom (a development of the UH-1N) and the AgustaWestland AW139.

[2] Specifically, the CF wanted it to be based on the stretched-fuselage Bell 205, which the service already had experience of, but instead powered by a pair of engines for a higher level of safety.

The Liberal Canadian government of the time had not supported US involvement in Vietnam and had also opposed US policies in Southeast Asia, as well as accepted US draft dodgers.

[2] Another key opportunity was the European market; Bell negotiated with the Italian helicopter manufacturer Agusta to produce the AB-212 under license.

[1] In United States Marine Corps (USMC) service, up to three radios would be installed in the cabin so that commanders could remain airborne while coordinating ground troops.

[citation needed] Starting in late 1970, mere months after receiving its first deliveries of the type, the USAF begun to re-equip the 20th Special Operations Squadron in Vietnam with UH-1Ns, supplementing and eventually replacing the single-engined UH-1F and UH-1P.

[6] Armed with miniguns (or 40 mm grenade launchers) and rocket pods, and painted camouflage with no US markings and only a Green Hornet insignia, the UH-1N supported Special Forces reconnaissance missions from Cam Ranh Bay.

In total, 205 UH-1Ns would be received, not including six VH-1N executive transports that were used to carry the US president and other high-ranking officials, operated by Marine Helicopter Squadron One.

[10] In Canadian service, the CH-135 Twin Huey was regularly used as a tactical transport, moving troops and equipment around the forward areas of a combat zone; medevac flights were also conducted.

CH-135s were deployed on multiple occasions to support United Nations peacekeeping missions in various regions, including Central America, Somalia, and Haiti.

[2] During the 1982 Falklands War, Argentina deployed a pair of Bell 212s to the airstrip at Goose Green where they performed general support duties, including the recovery of numerous downed pilots.

Fleet-wide upgrades included night vision-compatible cockpit lighting, crash-worthy seats for flight engineers, and installation of a terrain-awareness warning system and traffic collision-avoidance device.

[19][20] By March 2013, the USAF operated 62 UH-1N Twin Hueys, with 25 providing security at ICBM sites, 19 stationed at Joint Base Andrews to evacuate Washington-based government officials in emergencies, and 18 used for testing and training.

[22][23] Data from USMC UH-1N Fact Sheet,[55] The International Directory of Military Aircraft, 2002-2003[56]General characteristics Performance Armament Related development